M119 Viscous Fan mod & problems with aux. fan resistor-mod - PeachParts Mercedes-Benz Forum

ke6dcj · #1 06-28-2002, 03:03 PM

Here's an interesting comment by Stu Ritter, current technical editor of the MBCCA's "The STAR" periodical, and former MB shop-owner (35+ years experience), on overheating M119's and modifying the viscous-fan cut-in, as well as possible problems with the resistor-trick, and a lower temp. thermostat.

JimF, Guido, comments?

:-) neil
1988 360TE AMG
1993 500E
===========
> Thanks Stu! I was just getting ready to install a *new* radiator
> (mine's original 10-years old), and replace the viscous fan with a SPAL
> puller-fan at 2780 CFM, on an adjustable thermostat as well.

The problem is the viscous coupling. I've done a lot of work here
to get my car to run cool. Now, with 95 degrees in Denver and full tilt
A/C running, I'm staying under 90C. Actually, it only goes up to 90 when
I'm idling for awhile at a stop. It stays at thermostat most of the time
now.
I was seeing 115-120 under these conditions. I found that the viscous
coupling wasn't working as it should. I went through three of them, and
guess what, they all worked the same way. I discussed this with the
chief
MBUSA engineer. He said that is the way they are supposed to work.
The fan clutch wouldn't engage until the strip saw 107C which really
meant
110C air going through which meant the radiator saw 115-120C. If you
listen carefully to the fan you will see how quickly it cuts out. It
only locks
on when you get up around 120-125C which is really bad. This little mod
takes care of the problem and counters the factories pathetic
engineering.

I took the viscous off the engine. You can carefully remove the
bimetallic
strip which has the pin attached. Drill a small hole (say 4mm) and
thread
it (say 4mm). Get a little 4mm bolt with two nuts. There isn't enough
thread on that thin strip to trust the threading. Screw the bolt in and
double
nut it, one on each side of the strip. Bow the bimetallic strip around
1mm.
This will give you full tilt fan engagement right up to the high speed
disconnect
around 3,200 rpm. You won't believe the amount of fan noise. It's noisy
but the engine runs cool as a cucumber. For winter, I reach down with a
4mm wrench, loosen the nuts, back out the bolt the 1mm and have a normal
(ha ha ha) viscous coupling during the winter when I don't need the fan
howling all the time.

> Also, the resistor trick
> (http://pages.prodigy.net/jforgione/MB_CTS.html) hasn't helped enough. I
> can really feel the "retard" and loss of power when the engine gets hot.

There are problems with the resistor trick that took me a long time to
figure out. Don't do it. That temp switch provides a temp signal to far
to
many things to trick it the way I did. It shouldn't be done. Once you
study
the wiring diagrams, you'll see what I mean.

> BTW- Satish had mentioned some 70-C thermostat, but I can't find one.

DON'T EVER, under any conditions use a thermostat that is rated lower
than
the factory spec. There is no quicker way to wear out an engine
than to run it cool. It is better to run it at 120C than at 70C. At 70C,
the
engine
still thinks it's in the final part of the warm up cycle. Wanna talk
about
wearing
something out. Excess fuel will wear it out so fast it will make your
head spin.

You will also be running the cat with too much fuel for too long. No
good.
Disastrous
idea.

Stu

Date: Fri, 28 Jun 2002 10:24:45 -0600
From: Stu Ritter
Subject: Re: [MB] Viscous fan fix for hot M119s (Was: 124 aux fans on
all thetime)

> Stu,
> As someone who has never removed a viscous fan clutch, how hard is it?
> Also, for switching back to "normal" operation in winter, do you have to
> remove the clutch?
>
> Steve Wengel

The manual says to remove the radiator. We have been able to sneak
it out without taking out the radiator. Just take off the shroud.

Switching back does not require removing it again. Don't put the 4mm
bolt at the center of the strip but rather out toward the end. Just
figure
that you have to lift it about 1mm to get full tilt fan action. I have
done
it twice now and it takes a minute or two on a cool engine. When I go
to set the 1mm clearance, I use a screwdriver and pry the strip up
and use the screw as a set screw, rather than trying to use the threads
to set the clearance. Works like a champ.

I just came back from the shop. I had to deliver something. It's about
88-90 in Denver right now and with A/C on, it was staying at thermostat
temp. One needle width above the 80C mark. Just right.

Doing research for my book, I found that the temp sensor that I had
jumpered provided a signal to the LH-SFI injection unit that determined
mixture. My car has been running better since I removed it. I didn't
think to go past my nose when researching the resistor affect on the
switch and changing the value seen. That signal is looked at by both
the LH control module and the EZL/AKR ignition module.

Stu

yal · #2 07-01-2002, 11:24 AM

You can still use the resistor mod on the 190e 2.3 engine which has a seperate fan switch to turn on the electromagnectic fan.

Good post STU!

ke6dcj · #3 07-03-2002, 01:35 AM

I did Stu's mod, and boy can you hear that fan roar. And it does a great job. Driving in 85F on a 70% humid day, and the car never got over one-needle width past 80C at 90MPH, and never over 90C when creeping through a 15-minute delay at 10-20 mph.

The only problem, it sucks down power; which means you have to give it more gas to get it moving the same way, and gas mileage suffers.

I think I'm going to really look into electric fan (s) with a thermostat. . .

:-) neil
1988 360TE AMG
1993 500E

JimF · #4 07-03-2002, 11:33 AM

All MB autos that employ a separate CT sensor, B10/8 (M119 engine), use that sensor to control the A/C and Aux Fan(s).

Furthermore that sensor (B10/8) is not used to control the mixture, fuel mapping, etc. In short, it does not control any function that has to do with the engine or engine electronics!

Yes, it makes the A/C 'think' that it's a little warmer than it really is but no big deal.

The ECT sensor (B11/2) connects to LH-SFI module and is used to calculate air/fuel mixture and idle speed correction. Also the EZL/AKR module (N1/3) uses this info.

Stu's comments have nothing in common with my Cool Harness mod. He is mistaken!

Arthur Dalton · #5 07-03-2002, 11:49 AM

An added note to JFs reply..
Not only are there two seperate sensors, but the later models retained the same system but encased the two into one 4 pin connector sensor.
The single 4 prong still has two seperate thermistor circuits
[both with the same values] , but are isolated from one another electrically so as not to feed info from the aux fan one to the engine management FI/Ignition module....

If both were referenced for Eng management, then two sensor
circuits would be unneccessary...

Subman · #6 07-04-2002, 02:45 AM

JimF, and Arthur Dalton-
Are you 100% sure about the resistor mod. Stu is the editor for the Star and a former shop owner I would think he knows what he is talking about.
I just dont want anything to go bad on my car because of the fan mod.

neil-
I am interested in this mod you did. Dont know if I will keep the resistor or not but I would like to try the 4mm bolt.
Can you explain it a bit better then in orignal post. If you had pics that would be great. Do the aux fans come on more? I am just kind of confused on driling a hole and haveing my fans work better.

Excuse my Ignorance.

Subman

JimF · #7 07-04-2002, 03:06 AM

Subman, et al:

It appears that Neil has caused this problem because of comparing apples and bananas! However Stu Ritter's comments are also incorrect. Since Neil hasn't posted a 'clarification' of his initial post, I guess I will.

As I stated in the original thread, when Donnie (Benzmac) made the same 'shoot-from-the-hip' comment (as did Ritter), it too was not correct! Here's the thread, besure to read it. How to change Aux Fan cut-in point

So bottom line, my web page (my menu #17) that explains the theory of operation and the MS thread above are correct. As stated, the B10/8 sensor controls the A/C and Aux fans and does not affect the fuel injection, mapping, etc..

You car is safe!!!

Maybe Neil will favor us with an answer! He has sent me an email trying to clarify what he has created but has not yet posted here.

ke6dcj · #8 07-04-2002, 11:48 AM

Ok, here's what I think happenned, including me cross-posting from the Ritter-Easley Mercedes list and the Mercedes-shop forum:

1) Stu had written about jumpering sensor B11/2 which provides engine coolant temperature to the LH (engine fuel-management system) system- Stu realized this is wrong and posted that this was wrong;

2) Jim's research revealed that jumpering (with the correct value range resistor) sensor B10/8 which DOES NOT feed info to the LH system, only the air conditioning system, will fool the aux. fans to come on early;

3) In Stu's post about not doing it, there was no mention to the sensor he was referring to, so I incorrectly assumed it was B10/8; this caused the confusion.

In short, don't jumper B11/2, but do jumper B10/8.

Here are schematics for the W124 with M119 engine and LH; and the W124 M119 Air Conditioning system:
http://www.silcom.com/~neilv/sportline/images/W124-ACC-M119-LH-83-6.pdf
http://www.silcom.com/~neilv/sportline/images/W124-LH-M119.pdf

Regarding modifying the engagement point of the viscous fan (the thread that started it all!):

1) Stu is correct, the bi-metallic strip in front of the viscous coupler will not engage until heated until 107C. Unfortunatlely that means ambient air temperature will need to get to 110C, with a radiator temp. off 115-120C- NOT GOOD.

2) The bi-metallic strip is held in front of the viscous coupler with just four small tabs that can be bent OR, just gently bend the bi-metallic strip to remove it;

3) Once removed, you'll notice a pin that goes between the viscous coupler and the bi-metallic strip. The bi-metallic strip pops up and out towards the radiator about 1-2mm allowing the pin to move up. This engages the fan until about 3500-3800 RPM when it automatically disengages;

4) The mod, should you accept it, is to drill one 3.5mm hole into the bimetallic strip, and insert a 4mm bolt, such that the bi-metallic strip is popped up about 1-2mm; I did what Stu did and used a 4mm bolt and two 4mm nuts, plus I tapped the 3.5mm hole with a 4mm tap. I tapped the hole in the strip about 5mm out towards the end of the strip from where the pin and strip meet, or 10mm from center;

5) There is no doubt about it, this MOD works, however it does eat about 10-15 HP, and you fan is always on until the cutoff RPM.

6) Driving at night with 57F femps, the car gets to 82-84C, so the thermostat is open and I sill can get heat- in the day never past 90C in town, 85C on the freeway.

7) Don't try this unless you remove the radiator OR have access to special tools. I use a OM603 fan clutch holder tool, and the 8mm/10mm A/C clutch tools to remove the viscous fan without removing the radiator. You can find them here: http://www.technictool.com/

Hope this ends all of the confusion.

:-) neil
1988 360TE AMG
1993 500E

ItalianBenz · #9 07-04-2002, 12:04 PM

I am with Jim F. This set up has worked. Im not changing anything. Lets just be thankful,we live in southern calif and not
texas or AZ, with ambient temps scorching our cars would not be happy campers. I think Mercedes should of put in bigger radiator, since this engine is just rammed in that small compartment. I have a service bulletin from MBAG/stating our cars can run up to 110 C. and before red zone long as all system are operating normal.waterpump,fans etc. I'm going to find this bulletin from yrs ago,and post it on here.

My temp gets up to about 90-92 then fan kicks on and stays on for about 30-45 seconds then goes off.

thats all i have to say.

JimF · #10 07-04-2002, 02:08 PM

I believe that you have it correct. Stu tried to use a resistor across the B11/2 sensor, which is a no-no! That would explain his comment, ". . . loss of power when the engine gets hot".

Your schematics are very clear and easy to read. Tnx!

bdrought · #11 07-05-2002, 03:39 AM

Not sure how Jims mod affects this, but........

The worst thing for an engine is heat cycling...i.e. getting hot, then overcooled, then hot again. On the Elise there is a bit of a design flaw in that the thermostat is next to the engine, but the radiator is 8ft away in the fron tof the car. This water gets supercold. The moment the thermostat opens, cold water rushes into the engine. The Thermostat then closes quickly, and the water heats up. This repeats, and eventually the head gasket will go (or the head will warp).

My point is... it's better to have a car run at 110degC all day long rather than oscillate between 85 and 105degC.

Bri

JimF · #12 07-07-2002, 11:29 AM

Since Mercedes states that an engine meets specs at 80C, then certainly operation between, say 85C to 95C would be ok.

In fact most MBs do just that! Without A/C here in southern CA, my car runs between those limits. So I cannot believe that any damage will be done. My engine has 101K miles on it and is still running strong.

However, I do believe that running the car 110C all day long could cause some bad results. One that I can think of a severe retardation of timing at the temperature.

I do agree that cycling between 85C and 110C would be not the ideal operating conditions.

Interesting story: saw a '91 380SEL where the engine 'melted'!! The woman that owns the car let her 19 yr old son drive it and it overheated. The temp gauge was on-the-pin and he didn't notice anything wrong so he continued to drive it.

The car got so hot that the radiator MELTED! The plastic endcaps were deformed badly. The top 'plastic' pieces on the engine melted like glue! The engine froze 'solid' but, I was told, there was no smell of anything burning. That's hard to believe.

Engine was replaced along with the radiator and a number of other components. It runs great now!

#13 07-12-2002, 07:40 PM

I don't know much abt this but I had a 90' mbz 300e and it overheated once and I didn't notice it too, the car suddenly stopped and smoke came out of the engine bay, I towed it to a mechanic and he said that my block had cracked...I didn't know why..

but this was a few years ago...

David Hendy · #14 07-14-2002, 12:23 PM

I have done a little research into the electric fan upgrade. Say a pair of narrow puller fans mounted on the inside of the radiator, which should be able to move 1500-2000 CFM of air each.

A pair of 14 inch fans should do the trick, but will the alternator be able to cope with another 20 amp draw? What is the alternator rated for? Will I need to upgrade to a different alternator?

The fan upgrade should be a sub $500 conversion, and would probably give a few extra HP, as a not too inconvenient consequence.

Any thoughts?

Michael · #15 07-14-2002, 03:39 PM

Huge alternator-no problem as long as it's not the original (actually, mine IS the original & runs my nearly 100 amp sound system) which could be compromised.

ke6dcj · #16 07-14-2002, 06:35 PM

I was all set in installing the SPAL dual 11-inch fans to replace the viscous, at a whopping 2700+ CFM. Clearance was a big problem, esp. since they share the same center-line.

Independent dual 11-inch fans could fit if they were offset to clear the pulleys. Figure on a max of 4.0-inches at the motor.

I opted for a 16-inch SPAL puller fan at 2380+ CFM, and installed it slightly off-center for better clearance in the factory shroud (pics to come), along with a Derale adjustable thermostat that uses standard 40-amp BOSCH/HELLA relays.

Works like a charm, and doesn't eat all the horsepower of the viscous fan.

:-) neil

PS: I was told a 600SL alternator at 140amps will fit (my next upgrade)

David Hendy · #17 07-15-2002, 04:56 PM

I thought that a V-8 like our cars have need between 3000-4000 cfm fans? Are two small fans better than one big one?

How did you mount the fan to the radiator?

ke6dcj · #18 07-15-2002, 06:00 PM

The single 16-inch SPAL is doing great, keeps the car between 85-90C on a 85F day at 30% humidity.

If you order a SPAL fan from BeCooling, they have come with a nice mounting kit that has metal arms with various mounting lengths.

To mount to the radiator, I used three of the factory holes on the radiator lip, and drilled one other.

Yes, two would be nice, but you do lose the factory shroud.

The single 16-inch is to keep the car cool in traffic. I also did the resistor mod so that also kicks in (I set mine for 100C) when its very hot.

:-) neil
1988 360TE AMG
1993 500E

JimF · #19 07-15-2002, 06:18 PM

Did you remove the original viscous fan in order to mount the new 16" fan in the shroud? I think that is a 'yes'!

So now you have the dual 'pusher' fans in the front and the new 'puller' fan behind the radiator?

Plus you added the resistor (1.7K?) to cut-in the aux fans at 100C.

Did I get that right?? Pics would be great.

JimF · #20 07-17-2002, 08:51 PM

Another question re the vis fan mod:is it possible to modify it to cut in at say 90C rather than 107C as it comes.

That would probably mean that the radiator was at 95C or so. Wouldn't that make a good comprimise? Worth some thought.

I wonder how hard it is to 'tune' that sucker!

David Hendy · #21 07-18-2002, 12:34 PM

Do you think our cars could stand a hit from two 24 amp fan motors? What strain would that put on the alternator? Would the alternator take significant hp to drive?

JimF · #22 07-18-2002, 05:26 PM

The two (2) aux fans draw 30amps on HIGH speed (around 18 amps on low), so sounds like 48 amps would tax most any system.

Michael · #23 07-18-2002, 08:44 PM

I regularly draw transient peaks near 100 amps, no problem. However, the battery in these cases acts as a capacitor, so unless it's optimally charged or in exceptional condition there are draw issues.

David, in your case I'd pop in a new OE alternator, perhaps consider a new battery then let's talk in 3 years or so

David Hendy · #24 07-18-2002, 11:19 PM

The 600Sl uses the same alternator as a 500E, 110 amp. All of the S class use a 143 amp alternator, which is probably a good upgrade at $295.

Kenlowe fans in the UK make a pair of 13" fans which are only 3" deep and 24" wide for the pair. They come with an installation kit that includes an adjustable dial in "temp control".

I had a pair of Kenlowe fans on a 420 TVR I had in the UK, they were great.

BongC36 · #25 08-09-2002, 11:51 AM

I was VERY concerned with engine temperature because my C36 used to see 95-115C. One time 120C! Although MB says this is normal, I just aint comfy seeing the needly so close to the red zone. Also, timing is retarded as the temps go up.

Changing thermostats, fan clutch and coolant did not help since, as Jim noted, the clutch on the engine fan engages only at 107C, which in reality meant seeing 110C+ on the gauge. Not good for my heart.

Luckily I recently found some SACHS 'tropicalized' fan clutches. These units lock up at a much lower temp than the stock ones. Now my temps ranges from 85-92C, in traffic or at speed, here in my hot country, with the stock 87C thermostats in place. Oh Joy!

SACHS Lufterkupplung #2100 006 243 , Made in Der Vaterland

Hope this helps.

ke6dcj · #26 08-09-2002, 12:03 PM

Thanks BongC36. I saw these for the M104/M103 engines, but not for the M119 engine.

BTW- how much was it?

:-) neil

BongC36 · #27 08-09-2002, 12:17 PM

Too bad Neil. They work like a charm for my 104. Perhaps the mounting can be modified to fit your M119?

They cost about USD 105 here, but ALL imported items are too expensive here. I noticed that these new tropicals are somewhat locked up when I shut off my engine when the gauge temp is 90C, so they are probably engaging somehere close to the thermostat setting of 87C. When the engine is cold they are freewheeling so no roar at all...

ItalianBenz · #28 08-09-2002, 09:30 PM

I bet It might work. Alot of mercedes fan clutches adapt and bolt up the same. I really would like to get rid of the coolant mod harness and try something else. I know for a fact if you install a V-12 fan clutch, they kick in sooner due to the fact of a biggger engine and all. One old tech told me that was a cure for some of the cars that constantly ran hot.

BongC36 · #29 08-10-2002, 01:30 AM

This to me is the simplest and most effective solution to our high temp concerns. It keeps the engine in the lower half of the allowable temperature range and does not require any modifications. Putting in a bigger fan or tricking it to run more often impacts on a lot of other things, problems which this clutch neatly sidesteps. I even had to install a manual switch for the Aux Fans before, so anxious was I.

need2speed · #30 08-10-2002, 11:45 PM

I do enjoy reading all this "tech talk" but has anyone actually experienced engine problems from overheating their M119 in routine driving??

Going down to Vegas the past few summers from my northern habitat, I was scared *****less about overheating. Synthetic oil and WaterWetter were administered and off we went. A week of over 100 degree weather and NO PROBLEMS.

BTW, something possibly unique occurs up here that CAN cause overheating...poplar tree fuzz clogged up the radiator on our ML320. Solved with a bit of window screening

-fad · #31 08-13-2002, 01:17 PM

Which route contains the least amount of (-)'s associated w/ it????

CT sensor/ piggy tail: ("tricking it to run more often impacts alot of other things.....what things?):
> near constant low speed aux fan usage= premature or accelerated fan wear and increased alternator wear
>any elec. system/ load related/ relay (-) or extra wear issues?
>require eventual upgrade to the 143amp W140 alternator to support the near constant fan functioning?
> effective hp decrease?
>appears Guido, Neil, et al are wishing to/abandoning this method of dealing with higher temps.....JimF appears to standing as a proponent of this method

Fan clutch engagement mod:
>belt/ tensioner/ bearings premature or accelerated wear issues?
>fan clutch itself premature or acelerated wear issues?
> effective hp decrease?
> increased fan blade noise
> Q: except w a/c "on"- - - w/ this mod, will the elec fans ever engage due to a temp related function? (107, etc)

...inquiring minds want to know
-fad

ke6dcj · #32 08-13-2002, 06:47 PM

Unfortunately, the Tropical viscous clutch that BongC36 posted will not bolt onto the M119 fan which has bigger fan blades, compared to the M104 specific fan- which translates to MORE air.

A new M104 fan assembly will fit, but it might not produce enough airflow when engaged.

If you don't track the car, and don't mind the loss of HP when the viscous fan is engaged, the bi-metallic modification is simple and really keeps the engine COOL.

The dual aux. fans IMHO is not very efficient in moving air on the radiator side "pusher fan", hence the reason why I went with a single SPAL 16-inch "puller" fan. Moreover, with the adjustable thermostat, it's easier to adjust for track and winter/summer usage.

:-) neil
1988 360TE AMG
1993 500E

JimF · #33 08-14-2002, 02:22 AM

There's always pros and cons for anything. Here's what I see from my viewpoint taking ideas from this thread.

1)Pro: the Cool Harness (CH) is very simple, straightforward way to achieve engine cooling. It's easy to accomplish and the reward is high. Cost is very low, $0.04 for a resistor for DIYers! My commerical version is only $39.

2) Con: the use of the fans is a little greater than it would be without the CH so there's some 'wear-and-tear' on the fans and on the electrical system to produce it; about 18 amps. So theoretically there's some hp lost! Also there's some increase in noise due to their use.

Rebuttal: For a 315hp engine (S500), the extra amps from the 140amp alternator needed for the aux fans would in actuality, produce minimal 'drag' on the engine, so you can probably forget the hp loss. My gas milage is not changed since use of the CH.

As far as the fan(s) usage is concerned, it would equal the use of A/C. We all know that when it's used, the fan(s) come on low almost immediately in hot weather. Since it's our summertime, it's hard to penalize fan usage for either the A/C or CH. In fact, the A/C will cause much higher fan usage than will the CH.

As far as fan noise is concerned, in my S500, it's not detectable inside the car with the door open sitting in the drivers seat. So noise increase is really not a concern either.

When the use of external electrical fans is considered, the PRO is increased/better engine cooling without use of the aux fan(s). The CON is high(er) noise, some hp loss and wear/tear on the alternator. Since I've not tried this I can only rely on what has been posted in this thread and my engineering background. Also cost is considerably higher ($150?) than a CH plus a 'custom' install that takes some expertise.

The fan NOISE is louder and there is some hp lost because the power requred for it is higher than use of the car's aux fans. The current draw is almost constant, around 21 - 22 amps from 1180 to 2360cfm.

The alternator in non 'S' class cars is not quite as 'beefy', so 22 amps is probably noticable. So is the higher noise, some hp loss and cost outlay, outweigh/outperform the use of the CH??? In my mind, no!

Actually, the wear and tear on the car's system is probably increased with the use of an external fan. But the result is better cooling. So is that worth it? Is the additional cooling needed? Is it cost effective? Hard to say "YES" to any of those questions.

The CH is an effective use of the fans to get the 'best-bang-for-your-buck' in engine cooling with minimal wear and tear on the car's systems. The CH's cooling is 'close' to an external fan. Also it's very easy to accomplish by most any MB owner. Probably can't say that about an external fan mod.

One final point: If the aux fans are not disabled as Neil described (CH used above 100C), then the additional current draw increases the stress on the alternator causing additional hp loss [18 + 22 amps = 40 amps]!

What about hot/humid day, car driven at high speeed, then parked. When started again, aux fans will come on at high speed (30 amps) plus 22 amps from ext fan equals 52 amps.

or

alternator? Blown fuse? Welded relay?

ke6dcj · #34 08-14-2002, 03:11 AM

I just ordered a Race Tech accelerometer, and I'll do some measurements in the next couple of weeks of 0-60; 0-100; and 1/4 mile with the external SPAL fan, the Cool Harness/resistor mod; and if it isn't a pain, the bimetallic mod which means I'll have to remove my external puller fan, and replace with the modified viscous fan.

From the seat of my pants, the greatest loss of accelleration seemed to come from the modified viscous fan.

Both the Cool Harness/resistor mod and external puller fan, IMHO, felt the same during acceleration , however, the external puller fan definitely keeps the engine cooler than just having the CH as Jim stated.

In 85+F 70% humidity up a 15-mile 10% grade at 65mph, the CH kept the engine temps at approx. 100C. The same grade, with the external puller fan, and the engine temp stays at 90C.
With the modified viscous fan, 85C ALL THE TIME.

If you use a M104 fan blade and the tropical viscous clutch, (it will bolt up) I bet the results would be the same as the external SPAL fan. If so, the cost is about $140 for the fan clutch, and a used fan blad is about $25. The SPAL fan and adjustable thermostat is about $195.

The SPAL fan is definitely loud, but not as loud as the ROAR of the fully locked-up M119 viscous fan, also you cannot hear SPAL from inside the car.

I would try the CH/resistor mod first.

If you need more cooling, consider the M104 tropcial fan (clutch and fan blade), and change the value of the CH/resistor mod so it kicks in at 100C, OR remove the viscous fan and install a 2300+ CFM puller fan and adjustable thermostat.

If you don't care about HP loss, just do the bimetallic viscous fan mod. This will keep things cool ALL THE TIME, but definintely additional stress on the pulley & associated bearings.

The SPAL fan is on it's own relay and fuse, and on the hot days when the A/C aux. fans are running AND the SPAL fan as well, I have NOT experienced any blown fuses or welded relays, including during startup after a hot run.

:-) neil
1988 360TE AMG
1993 500E

BongC36 · #35 08-14-2002, 06:29 AM

Neil, do you know by how many degrees the engine timing is retarded with increasing temperature? I read somewhere that for our 104s the timing is retarded by 5 deg for every 10C rise.

I ask because my motor feels more lively now that my temps are 85-95C only. Perhaps the fan HP is offset by the timing gain?

I remember from reading a lot of old posts that the torque monster M119 engine is very sensitive to temperature.

I think the tropical clutch is engaging around 80C. Twice I shut off the motor when the gauge was reading 80C and the fan was still free-wheeling. When I shut off at gauge=90C the fan is locked.

-fad · #36 08-14-2002, 11:16 AM

Jim, Neil, and Bong- - excellent information!

Thanks for sharing your tech expertise and real world experience.

fwiw-
Last weekend, we enjoyed a trip from San Jose to the CA Central Valley trouble-free in the E500 (41.7k- Pearl Black/Black):
>over 300 miles (w/ CT Piggy Tail)
>MB coolant + 1 bottle Water Wetter
>Fresh Penzoil LongLife 15W-40 dino/ OEM filter
>Chevron Super 91 Octane
>95-109 degree ambient dry temps
>90% highway/ 5% City/ 5% stop-and-go freeway parking lot
>a/c on 100% of the time, climate control @ 72 degrees

=coolant temp per gauge reading-held consistent @ 95 (low speed fan noise not detectable from inside the cabin)

>>I do pop the hood when parked (as often as I can) to help that pizza oven heat escape

The previous weekend, we enjoyed another enjoyable road trip trouble free from San Jose to Bear Valley/Yosemite in the E320 Coupe (105k- Black Opal/ Gray):
>350 miles (no CT mod), w/ some mountain ascent
>new Behr rad/ MB coolant/ NO Water Wetter
>Fresh Castrol 20W-50 dino/ OEM filter
>Chevron Super 91 Octane
>4 passengers + full trunk
>100% highway: ambient temps 80-90 degress
>a/c on 100%, climate control set @ 72

=coolant temp per gauge reading never went over 100 degrees

best regards
-fad

JimF · #37 08-14-2002, 11:43 PM

Look what I found today!

My car always warmed up slowly even in warm weather. So decided to check the Tstat today. Replaced it with a 80C TStat and when I had time to look at the removed one, that's what I saw. It stays open about 1/16" (the reflecting light makes it look larger) so that explains the slow warming. It opens fully at 185F and beyond but closes down to be open as shown

With the old Tstat, my car would run at around 85C until going into stop-go traffic, then it goes to 95C.

With the 'proper' working Tstat, the car warms up quickly and now runs about 90C.

On the road it holds at 85 - 90C. Exiting from high speed driving, into stop-go, it goes to 95 - 98C.

Wondering if I should put the old one back in??? If this was Buffalo, then I wouldn't say that but here in SD, it's pretty warm.

Comments, please?

ke6dcj · #38 08-15-2002, 10:29 AM

Jim- I would replace it with a new Factory MB thermostat (just in case the new one causes problems, your dealer will have to honor replacing it (parts & labor) for one year).

It might be a good time to change out all the hoses and radiator, or at least give them a good inspection.

Someone else mentioned drilling a couple of small holes in the thermostat to keep the temps down. Perhaps this is why you had different and better results in your cooling mod than most of us . . .

:-) neil

-fad · #39 08-15-2002, 11:00 AM

Hi Jim-

(though not an engineer, scientist, or tech) just wondering:

....if the M119 combustion/ injection/ O2 / cooling/ lubrication systems operate happily (equally no problemo) in the 85-105 range- - then perhaps the best case scenario (Ans) lies in recognizing +/- wear and tear issues between the alternatives:

>will the +3-5 or so increase in average operating temps (new t-stat) over time yield a signifant increase wear and tear of the vehicle? ie engine, engine compartment inhabitants, chassis, etc.

>will the slower warm up time (richer fuel condition) over time effectively yield a higher wear and tear on the motor and/or assoc. components? ie Cat/ O2 sensor

I've observed the E500 warm up to full op temp within 3-4 blocks of driving (sitting overhight), and the E320 Coupe warms up to full op temp within 6-9 blocks of inital driving (sitting overnight) South Bay SF Bay Area morning temps are in the 55-65 degrees.

imho- seems like I'd rather have a T-stat in use that is able to close and open fully to ensure that the systems have the full capacity to work together as designed....in either case, you have the cooling harness to regulate on the most critial upper end temps.

Last I read your sight (also recognizing) you've adjusted your coolant to compensate for more of the SD climates/ summer use ie ~60/40% H20/Antifreeze/Water Wetter- - so you've got all the bells and whistles and icing on the cake.

Best regards and looking forward to reading more of your thoughts.
-fad

JimF · #40 08-15-2002, 06:10 PM

After "burping" the system this morning, the temps are more like what they were with the old tstat.

Had drained most all of the old af/water out of the sytem since I was going to replace the tstat. What a stinken job trying to get that small 3" elbow hose back into place.

Taking the car out today, here's what I measured:
1) initial warmup is still quicker; from dead cold to 80C in about 5 minutes.
2) driving on the freeway; car held between 85 to 88C.
3) going into stop/go from freeway speeds, temp goes to 95C.
All of this is with A/C on. About the only difference is the quicker warmup.

Yes, I use 60/40 (w/af) ratio with 1 bottle of WW.

Without A/C:
1) same
2) car runs 82 - 83C
3) temp to 86 - 87C

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