W124 Aux fan upgrade -- Single to Dual
 

Hi guys,

This is a continuation from a prior thread.
In short, I want to improve the A/C performance while helping lower engine temps during the HOT summers here in Phoenix.

A) Anybody ever done this upgrade?
B) Will it work with the original condenser on my model?
C) Aux fan brands...Is "Metrix" any good? Its $50/each vs $125/each ACM
D) Can you replace them without removing condenser + radiator?

Much appreciated!

If I were you I would see if I could source a set from the junkyard. Replace the bearings on the fans and you should be good to go. I've got like 10 bearings I bought a while back, havent gotten around to doing it yet.

Here are the bearings that you should use. I found them in a thread a while back.
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=140677210093&ssPageName=ADME:L:OC:US:1123#ht_937wt_905

Here's a parts list EDIT: Just realized I used the wrong chassis, but these are the same for the 124.090 as well. Looks like dual fans was part of the 89 facelift.
http://i.imgur.com/SLw7Xl.jpg

From the looks of it... should be removable without having to take the condenser out.

ps,

I hope you don't think I'm picking on you or anything, but am I correct in remembering that this car was an original R12 car converted to 134a? If so, if you want to improve the performance of the a/c system, there's nothing you can do that will improve it as much as reverse converting.

You are in a TOUGH a/c environment, and a converted system is just not going to perform like an R12 system. From the results of some of your earlier posts where you gave your temperatures, it's obvious that you did a great job in the conversion, but you are REALLY handicapping yourself.

If I remember incorrectly about the conversion I apologize.

Best of luck with it.

If you want twin fans that can make their own tornado then get a pair of curved blade SPAL HD fans and wire them up, you can use a larger wattage resistor to step them down and you can start with the original impedance Beru part used in later cars along with separate fuses for high and low speeds, because when the two fans kick on high from a standstill the amp draw is quite large. If they are just stepping up from low then its not a problem.

anyway, I have seen a very nice system on a 88 300E, it was using its own condenser but with dual fans - the fans were being controlled by a standalone controller that sped up and slowed down the fans depending on the condenser fin temperature. The A/C performance was pretty good IMO.

No you are right, Larry and I am planning to convert back to R12, but if I am, I want to replace the compressor since its been so long as R134a and since I will have to completely remove the compressor, it seems pointless at this point to not either replace it or rebuild it. LAST thing I would want is to convert, then have either a compressor failure, or have the expensive R12 leak out next year.

Its in the works for the long run, but right now I am buying a house so I can't drop $500 to do a full system replacement and back conversion :) But I figure I can boost A/C performance temporarily and of even greater amount when I back convert.

I'm reading that it may not fit on the older style condenser because of the shroud used.
What about another option of fitting one larger single fan or would two twin fans as mentioned above work better?

Looking forward to your results from the swap!

-J

If anyone needs them, I've got the complete dual fan set-up in a 1995 E320 (98K miles) that I'm parting. They worked perfectly. $78 includes shipping in the contUSA.

Hmm.
the shroud used, on a newer 124 should fit any other year 124. I plan on pulling the fans from my gasser parts cars, and installing them on my 87 wagons.
the condenser does not need to be changed, HOWEVER, the newer condenser from 93 up were DESIGNED to operate on 134, so they are better as well... I'm just sayin...

The problem with the newer M104 condenser on the M103 single fan models is that the ac hose is different and will need to be replaced. Because of the different sized and placed air intake apparatus, the hose can not be routed as it is on the later models and the fuel chiller cannot be connected. I've never tried to do it with the 90 to 92 M103 W124 sedans' version of the condenser, so that may work with the older style hose.

On the W126 at least, the dual fan mounts are different on the condenser... meaning the late condenser only works with the dual fans.

Hope it helps.

BTW, big issue is the M103 cars have a puny fan blade so low speed airflow over the condenser is comical at best. Yes, even the 'updated' fan is crap. Compare that fan blade to the BMW M30 fan from an E32 or E34 and you will see the difference.

I tried to fit my SDL's fan blade and while it bolted up, the blades are pitched the wrong direction. I looked at it forever and could not find a simple retrofit sadly. This alone would make a huge difference on the M103 cars as they have a puny radiator too.

Just thought I'd add my 2¢, I live where the climate is triple digits and my a/c was converted to r134 and I did have problems with cooling at first (which turned out to be my heater valve not closing off coolant). I have since then bypassed my heater core and and added a resistor, recently to turn my aux fans on high around 90°C and my a/c gets around -50°F. It was getting around that cold once I bypassed my heater core last march. I only added the resistor because I noticed my car ran hot with the a/c on. Before converting back to r12, I would definitely try to make sure there is no coolant running to heater core and make sure your refrigerant is at the proper level. I added the refrigerant that is sold at autozone with the polar bear on it and just used the gauge it comes with. it took all but a few minutes.

yep - them BMW fan blades pull a great lot of air.. and yes the 103 fan blade looks cartoonish to be a fan blade for a large engine.

Today from engine cold 104F, freeway vent temps were 50F after 15mile drive...

BUT 2hrs later still 104F ambient....15mile drive back home, Engine HOT, freeway vent temps were 60F, and once at the stop light, it was at 70F from vents.

That is with Aux fan running on high.

As you can see, the issue seems to be that the condenser cannot shed the heat once its warm! I see the only way to get decent vent temps is doing a full upgrade along with back converting to r12.

Hitman you said the fuel cooler cannot be used? Did they remove it from the later models?

Yeah ps, unfortunately you're dealing with some extremes there. Sounds like the engine compartment is hopelessly heat soaked at that point.

Just curious, does this car still have the belly pan? What is the condition of the radiator?

With a super high ambient like that, there's no room for even the slightest variable. A radiator that is even off of max efficiency by 10% would be playing into the equation. If the flow across the radiator were even a little bit blocked by debris or bent fins, it would play into this situation.

You're just operating at the extreme end of spectrum. In about a week I will be dealing with an ambient pretty close to that. We expect to see triple digits middle of next week and still have some humidity hanging around to go with it.

Thanks for keeping us informed on all this.

Exactly its just heatsoaked and cannot rid of anything at all.
I installed the belly pan recently for the first time...but the difference was negligible.

Do you think doing the upgrade and back conversion is worth it, or will it seldom make a difference other than whats in my wallet?

My girlfriends CLK320 A/C is just no comparison to mine...in 2-3 minutes hot or cold, the cabin temperature is nice :rolleyes:
and she doesn't even have aux fans on the front. Just one large fan on the engine which looks like its freewheeling most of the time anyway.

What would be good, is to have someone who lives in my climate who HAS a late W124 ('92-'95) with the upgrades I am looking for and for them to share how theirs acts in the climate I am faced with.

A good condenser and radiator fin cleaning really helps. In my late 124 (R134 from factory), I could see light being passed through fins of both heat exchangers but I could also see fluff stuck to the condenser fins.

I cleaned it out with regular home depot evaporator coil cleaner after removing the front fans and the radiator too, It really helped in A/C performance.

Add a combing to what Zulfigar recommended. You can get a comb from the a/c supply houses that will let you straighten the fins more quickly than any other way I've found. When you take the condensor out for any reason, you should always straighten up the radiator fins as well.

Hope this helps

OK, I can see where those vent temps aren't going to cut it - BTDT. You should be getting better performance. I just checked the NOAA website for Phoenix, and although the ambient temp is 103, the dewpoint is 34. That means your ac system doesn't even need to condense water out of the air to make you comfortable. The latent heat of water is very high (hence the reason it makes a great engine coolant), so this represents the removal of a very large heat load from the ac system.

The 10F temp difference between idle and highway is normal on these older cars. The compressor just doesn't have enough output at idle to produce colder air, regardless of how well the evap and condenser are working.

On your data above, was one drive early in the morning and the other with the sun overhead? The difference in vent temps could well be due to the difference in solar load (i.e. infrared heat) the car is absorbing.

How confident are you the recirculate actuator is working correctly? The 124 has 3 recirculate positions - 0% (fresh air), 80%, and 100%. The vacuum actuators - there are two for recirc function - have two seperate vacuum chambers. Applying vacuum to both delivers 100% recirculation. The portion of the actuator that takes it from 80% to 100% seems to fail more frequently. Perhaps you have only partial reciculation? It's easy to check if you have a handheld vacuum pump with a guage.

Finally, how clean is your evaporator? IMHO much of the improvement I saw after replacing everything on my 124 system was because it had a clean evap, where none of the fins were blocked or coated with insulating dust and dirt. Quite simply, the new evap had the ability to absorb much more heat from the airflow over it. These early 124 cars don't have cabin air filters, so the evap tends to get rather crudded up.

Enough rambling for today,


- JimY

1) I have cleaned my evap, but when I pulled it here was how it looked -- as you can see, pretty clean surprisingly:
Also, when I pulled on the actuator via the door, I heard hissing, so I know its working, but maybe the 80% setting is not? I'll have to pull the glovebox to test it I guess.

http://www.w124-zone.com/downloads/p...eaning/e15.jpg

---

2) So are you saying the later model W124's do not use a parallel flow condenser? The only difference is in the in/out port locations? They do look similar...I just "heard" that the later models used the parallel flow for the improvement in efficiency.
1994 E320 Condenser:

http://img.eautopartscatalog.com/hir...300&height=300

1988 300TE Condenser:
http://img.eautopartscatalog.com/hir...300&height=300

3) Lastly, what exactly makes brand new cars' A/C so much better than our old systems? I mean the main principles are the same, so is it just something like bigger compressors/condensers/evaporators?

I think it'd be worth your while to check the vacuum actuators. It's about a 30 minute job, assuming you have a mityvac. Check all 7 and let us know what you find.

I've owned and serviced both early and late 124 cars. The condenser on both looked very much the same with the only difference being the location of the inlet/outlet to accomodate the differing manifold hose assemblies.

A couple of things are different on new cars. They use parallel flow condensers from the factory. They have gigantic electric fans to move air over the condenser and radiator. Have you ever heard a late model Benz spool up into maximum cooling mode - it sounds like a jet taking off. Finally, and perhaps the most significant, is that new cars use variable displacement compressors. This allows them to keep the low side pressure at the ideal ~30lbs across a wide range of airflow, heatload, engine RPM, etc. which provides better cooling, especially at idle.

I will go buy a mityvac and test the actuators next week.

So to wrap up, there is no size difference, or design difference between the two condensers other than port location?

What about an alternative single fan upgrade to the stock one that would push a lot more air?
and what about finding a condenser from a later model that is parallel flow?
Maybe I'll pop my girlfriends hood on the CLK320 and measure her condenser size.

I'm a bit late to the discussion but have you considered replacing the main (belt driven) radiator fan with a big electric one?

Engine cooling is not really an issue, its the condenser temp. If I keep the A/C off, even at 110C, engine temp is like 90C. With A/C on, it'll add 10C or so, even on the freeway.

The big fan will be an electric puller fan, so it will help cool the condenser as well as the radiator...I would think. I would only try it after you've swapped up to dual fans and you find that they are not quite enough.

If you installed a good puller fan you could dump the pusher fan up front. I hear the ones from 90s Ford Thunderbirds are about the right size and move a lot of air.

-J

I was doing some reading through this thread:
http://www.peachparts.com/shopforum/diesel-discussion/301165-condenser-size-ac-condenser-3.html
and...
http://www.a1electric.com/spal/faninfo.htm

So I think I need to concentrate on getting the temperatures down on the freeway first -- aka the fans are pointless changing first since it struggles to cool on the freeway regardless. If I can get the condenser to cool down on the freeway, I can tackle the fans later.

Thanks for the information guys it helps me figure out what I need to do.

I'll consider switching to the big electric fan in place of the fan clutch too.

According to an old mechanic - the engine fan should take care of nearly all the heat load, the fan upfront the condenser is just to help the main fan heat up and engage to pull air.

I saw a very strange looking shroud on some W124 300E in UAE, it was not original, it was 2 pieces top and bottom with buckle clips and a yellow warning sticker on it that said - engine fan, which made the fan sit quite deep in the shroud. The shroud was installed to cope with the additional "crazy" heat load that UAE sees, and according to the owners it did work.

Don't forget to take into account the capacity of your electrical system and alternator when converting to an electric fan. Newer Benzs have 150 amp alternators. I don't recall what is on the 124, but not sure it's much more than half that size.

You've probably found ackits.com on the 'net, but just want to mention it here. They have bunches of generic parallel flow condensers to choose from. I think they are even local to you.

And the same google search that turned up ackits dug up this thread, which has the results of my 124.193 wagon ac rebuild. It's 8 years old, but has facts and figures on 124 discharge temps and high/low side pressures with R-12 and R-134a. http://www.peachparts.com/shopforum/diesel-discussion/99598-1982-300td-r134a-conversion-parallel-flow-condensor-update.html

Cheerio,

- JimY

According to an old mechanic - the engine fan should take care of nearly all the heat load, the fan upfront the condenser is just to help the main fan heat up and engage to pull air.

I saw a very strange looking shroud on some W124 300E in UAE, it was not original, it was 2 pieces top and bottom with buckle clips and a yellow warning sticker on it that said - engine fan, which made the fan sit quite deep in the shroud. The shroud was installed to cope with the additional "crazy" heat load that UAE sees, and according to the owners it did work.

@ps2cho.

You should look into the heater valve too. The original system has a bleed that if allowed to constantly bleed will cause the heater matrix to heat up.

De Je Vu all over again!:)

About 8 years ago, I was getting too high vent temps and Jim Yuhn wrote something VERY SIMILAR to what he is writing in this thread. I ended up pulling the glove box insert and indeed finding bad recirc pods. This led to the fifteen hour job of pulling the dash and replacing ALL pods. I checked them a month or so ago and they're still good.

In the course of ps, talking about his good vent temps I completely discounted the possibility of no recirc as a problem.

Jim to the rescue again!:D

ps, on the one hand, I hope you find bad recirc pods so that you can find your problem. On the other hand, I hope you don't so that you don't have to pull the dash. Big job!:(

Best of luck

I remember a 124 article done by ackits a long time ago, and they basically said that it was the worst candidate for 134 conversion they had ever seen. Maybe that's what led to the major league souping up of the system.

Thanks for the thread...
He mentions:

100F ambient
"So to compare the 2 lets discuss the differences. The 240D has no tinting. I run R12 in a standard system with pressures of 22 low and 265 high. The 82 300TD has R134a. A NEW evaporator as well as everything else. tinting, legal tinting, and a parallel flow condensor. R134a and the aux fan is on all the time. I'll try the system with it in the normal mode."

Well I am getting like 60psi low and 340psi high...and I am not overfilled. I am in fact, almost underfilled. FSM states I need 80% of R12 amount, I have 60% in the system. It was less than 2x12oz cans, so about 20oz. I was concerned over the high pressures, so I completely flushed the system thinking maybe it was overfilled with oil or sludge and replaced the TXV and drier, it dropped pressures a little, but not much (it was 65psi low and 360psi high before) INCLUDING aux fan on high the entire time. The system just stopped taking anymore out of the 2nd can. I put it in ice water ran at 2000rpm -- wouldn't take it in and no wonder with those pressures...

What kind of cold temp. are you getting at the vents for both cars? The car I picked up recently claims it has 134 in it without the proper nipples. I suspect it is still R12 inside. Will likely get rid of the 134 and return system to R12.

Unfortunately enough time has passed that I have no recollection how much R-134 was used in my conversion. I am thinking it was about two cans, so roughly a 60% charge.

If you're seeing 340/60 with the engine running at 2,000RPM, then I think you are overcharged. I suggest recovering some refrigerant until the low side settles in at 35ish PSI with the engine at 2,000RPM. Don't fixate on the 80% rule for converted systems, focus on the pressures. You want to hit the target low side pressure without exceeding a reasonable high side pressure - that's how I charge conversions.

Remember, the boiling point of the refrigerant is controlled by the low side pressure. The lower the pressure, the lower the temperature at which it boils. If you have 60PSI low side, about 60 degrees is as cold as the evaportor will ever get. (Need to look up the temp for 60PSI for R-134a; I don't have a pressure/temperature chart handy.) In an overcharged system the rise in low side pressure means the evaporator will never drop below the corresponding temperature, regardless of whether enough BTUs can be removed or not, hence resulting in inadequate cooling complaints.

Here's a chart:
http://www.idqusa.com/app/_files/Ima...art-33776F.jpg
http://www.idqusa.com/app/_files/Image/r134apc(1).jpg


It looks like you're pressures are too high. I'd agree with jcychun, looks like a bit overfilled. Back it down to the recommended levels in the chart and check performance.

I've had SEVERAL conversions end up in the 60 to 65% range. I haven't done one in a while, but if I did, or I was recharging one already converted, I would start with 60%.

My best conversion has been my 88 Vette. It has 65% and makes 38 at the vent even on a really hot day. I was amazed at this because a bunch of people told me that they were terrible candidates for conversion.

I agree that your pressures are high. If using less than 60% improves system performance this will be close to amazing, but also very interesting.

Thanks for keeping us posted on all this.

As I said, I am not overcharged. I have less than 2 cans in it. 20oz at most.
I've evac'd and recharged 3x total. Im not overcharged....

60 PSI on the low side at 1000 RPM is still way higher than I would expect. If you tap on the TX valve does it change?

FWIW at that RPM my car is at about 25 PSI. At idle it is at about 40 PSI on the low side.

-J

That is a fantastic idea to bypass the heater core but I need to know more about the resistor, is that because you want the fan running more often?
tx carmen

Doing some thinking....

What about creating a misting system for the condenser? I bet that would resolve all issues extremely cheap since I know my A/C can pull 40F from the vents on 90F days.

Radiator Mist Cooling System

I still have the lines for the OE wiper unit, but I have aftermarket DEPO Euro headlights now....so I have lines pretty much running both sides if I could make it work with the washer reservoir.

For what it's worth, I suffered from inadequate a/c in my 88 300CE for a long time, replacing various parts. When I finally got rid of the original compressor and replaced it with the 90-95 version part # 0002300511, it finally dramatically improved. Since then, I have no complaints about it and my kids in the back sometimes complain they're too cold.

The 0002300511 compressor is made for R134a, so it must be better at cooling at the higher pressures.

I was reviewing the wiring diagrams for the the W126 with dual fans, and according to the FSM the high speed isn't fused :eek:

My car has an un used strip fuse location, I might install one for the high speed.


Sent from my iPhone using Tapatalk

My 190e 2.6 has twin fans ahead of the condensor...
Could be made to work...

This sounds about right, I don't recall encountering any in the cars I've worked on.

My 190E has dual fans that draw about 30 amps total. I have them modified so that I can turn them full power manually. I've also removed the resistor..

I probably should put a fuse on the power line though. It comes off the battery and runs to two relays (one for each fan)... I think I actually used the car's old alternator cable as the wire.. (since upgraded to 0 gauge for the 143amp)

I just did some testing on my car. Three observations:

I tested the draw of one fan running at full speed. Pulled about 8 amps running, startup was about 12. Double that for both fans.

The factory seems to have made an assembly error... my car had a 40A relay in place for the low speed, and a 30A in place for the high speed.

As I said earlier the high speed function is not fused on my car. My fuse box has an un-used spot (16), I plan to install a fuse here for the high speed function It is one of the normal bullet fuse holders, so I can install a blue 24 amp fuse. I'll post instructions when I do this.

Thanks,

-J

IIRC the high speed functions because the fans are triggered by the sensor on the valve cover (typically a blue insulator for M103). When the fans run on high speed the compressor disengages.

I noticed that with my 190E, if the car starts moving the AC gets colder. But when I slow down, the AC does not blow as cold. When the auxiliary fans kick in low speed, then the AC blows cool again.

There is more current required for the low speed because of the pre-resistor, from what I understand. At full speed, the fans bypass the resistor (triggered by the blue insulator sensor mentioned earlier) so they do not need as much current.

My 190E does this too. It gets warm-ac at idle. I've not really observed a difference with the fans on vs off. I have my pre-resistor removed so fans are on all the time.

I think you've got it backwards though. The resistor acts as a current limiter.

At full speed, the fans will run at 13V @ 10-15 Amp/each. I know my dual setup pulls about 30 amps total at full speed. I checked with a DC clamp ammeter.

At low speed, the fans might run at 13V @ 5-8 Amps/each. Thats just a guess but I think its fused to maybe 16?

Nope, the resistor, while not 100% efficient, does reduce the power draw. That's how the fans on my car can be on an 8 amp fuse for the low speed.

-J

I'm also trying to "improve" my ac performance, I have an 87, compressor was replaced to a larger 17c (And i'm now running r134, r12 is getting harder to come by here) and the evaporator and housing was also replaced to a much simpler underdash unit,... it's hidden, you couldn't tell its been modified... :) Anyway... the only thing I haven't replaced is the condenser. Does upgrading to the more recent r134 condenser matter at all? Will it improve AC performance AT ALL?