New 95 E320 Hd Gasket - Runs Hotter Now - Page 3 - PeachParts Mercedes-Benz Forum

TomLatos · #31 10-05-2002, 07:49 PM

I will measure the concentration of the coolant as suggested. Sometimes it takes awhile for a good suggestion to sink into my head and will let all know.

And it will be a week or so before I pull the rad and flush. My mom's '89 Buick is acting up, I need to get that machine back in-line on a priority basis before again attacking my little MB problem. My dad, who instilled the DIY in me, is now blind, so it's payback time.

So stay tuned, and I will let all know of my progress, but my next post will be at least 1 week from now.

stephenson · #32 10-07-2002, 08:25 AM

jsmith,

I don't understand why an 83C tstat would make a difference in maximum temperature when compared to an 87C tstat ... doesn't the tstat (assuming normal operation) simply determine the minimum operating temperature? (the "curve" to the increase side might start 5C higher, but this would still not drive the maximum temp, right?)

jsmith · #33 10-07-2002, 09:05 AM

Arthur Dalton has already tried a 79C thermostat which got his car running even cooler but it got the engine running more on th rich side. This was the thread that got me going:

Overheating Thread

I'll wait until I run into what I consider the acid test, which is a couple of hours of stop and go traffic around NYC, to pass judgement on the 83C thermostat. So far, my max observed temp has been 90C. I'm even considering getting one of the tropical duty Sachs VFC's - that would make for multiple overheating countermeasures just like JimF has done with his engine...

stephenson · #34 10-07-2002, 10:01 AM

Yeah ... I do think a vclutch that clutches earlier in the temp rise cycle would be very cool indeed!

I will likely modify mine next time I get into the front of the engine or cooling system.

a2aa · #35 10-07-2002, 10:05 AM

try this..

http://pages.prodigy.net/jforgione/MB_S500.html

just some suggestions that may or maynot apply to your car, but LOTS of info!!

a2

suginami · #36 10-07-2002, 03:31 PM

Quote:

Originally posted by stephenson
Yeah ... I do think a vclutch that clutches earlier in the temp rise cycle would be very cool indeed!

I will likely modify mine next time I get into the front of the engine or cooling system.

It's not the viscous clutch fan that engages early, it's the high-speed electric auxilary fan that engages at a lower temperature, and continues to run until 82 degrees centrigrade.

jsmith · #37 10-07-2002, 05:40 PM

suginami,

the Sachs "tropical duty" VFC is for M104's and will lock at around 90C. this effectively turns the cool harness into a failsafe instead of an active component in the cooling system. i am tempted to order one. the VFC mod that JimF has on his pages locks the VFC via the added screw (they don't have a "tropical duty" VFC for the V8's). maybe in the future a VFC bimetal strip replacement/upgrade will accomplish the same thing..

suginami · #38 10-07-2002, 05:46 PM

Oh, I thought they were talking about the "cool harness".

This is the first I've read of this Sachs VFC (viscous fan clutch?).

It locks up at 90 degrees? Geez, my car runs around 92-95 degrees everday on the freeway.

What temp is the stock VFC supposed to lock up at?

Is Sachs the manufacturer?

Where do you order them and how much do they cost?

jsmith · #39 10-07-2002, 06:55 PM

the stock one locks at 107C - but that's actual temps around the viscous fan clutch, which equates to around 120C coolant temps. (this came from an article in MBCCA's "The STAR" ). in other words, too late. the tropical duty clutch is discussed in this thread:

overheating solved

i got a quote for $160 using the part numbers in that thread. i just did a search with the various parts suppliers and gave them the part number. i'm sure it can be had for less since the price in the Philippines was $105.

BTW i think the article in "The Star" was the basis for the VFC modification described in JimF's pages. the tropical duty clutch has the advantage of working just like the regular version up until lock up. the VFC mod with the screw is manually locked and unlocked (say for winter use).

chowpit · #40 10-07-2002, 07:33 PM

Its time to step back and huddle. Two things I would suggest checking are;
(a)make sure the cooling system is properly bled. I have seen the bleed hose become plugged with casting material if the engine was severly over heated. With a cold engine, remove the reservoir cap. Remove the bleed hose from the radiator and blow into the hose. Air should pass freely through the hose.

(b) make sure the radiator is not partially plugged. The easy way to check this is use an infred red temp sensor and check the radiator temps from top to bottom, with engine at operating temp. The readings should be fairly consistent across the radiator.

Another note: If the center of the radiator is plugged it will be cooler than the rest of the radiator and not allow the viscous clutch to engage.

HTH

TomLatos · #41 10-08-2002, 01:49 PM

Chowpit!

Excellent suggestions on the bleed hose and use of an IR temp probe. One question on the use of the IR - can this be done will all equipments in-place, or do I have to remove stuf (and what) to get an accurate IR reading. Also what is the recommended operating conditions to take the reading?

My plans are still to pull the rad this weekend. I will keep you all posted.

jsmith · #42 10-08-2002, 04:01 PM

i've seen an application guide for using just such a noncontact ir temperature device to diagnose a clogged radiator. haven't seen a report of this beeing done on this forum though. it's literally point and shoot and you go over the entire radiator area to check & compare readings. i think removing the fan shroud might be sufficient.

i'd like to hear Chowpit's view on the fan clutch lock up issue since he mentions that the radiator, if clogged won't pass enough heat to lock the clutch. the bimetal strip that controls the locking supposedly triggers at 107C which will need radiant / convection heat from the radiator whose surface tmeps will have to be at 110-115C. the coolant will then have to be at around 120C for this to happen (BTW this is information from Stu Ritter, the tech ed over at Star mag). it certainly sounds like stock fan clutches never lock at normal temps.

i also keep reading about these "failed" fan clutches. i understand that shear characteristics of the clutch fluid deteriorate over time and eventually it will be slipping too much to provide sufficient cooling in its "freewheeling" mode (really a controlled slippage). as to evaluating a fan clutch - i saw the "spin it hard when cold" approach (no more than half a rev), to the shutdown of a warmed up engine (2 second spin down?). is there a correct procedure?

400E · #43 10-18-2002, 07:21 PM

So, Tom, what's the (hopefully) good word?

chowpit · #44 10-18-2002, 11:42 PM

Yes, you can use the IR with all the components in place, eng temp normal, not running. Since you have the 2 piece shroud, its no trouble to get it out of the way. Measure the temp of the upper and lower hoses to give you a base reading and go from there.
I started doing this because I got tired of burning my hands diagnosing these things.

As for the clutch lock issue the specs Joe mentions are correct. I can say that the clutches on both of our 124s come on before the 107C. They usually kick in at approx 100C, sometimes less. I hear them roar alot during the summer months. The most common cause of fan clutch misdiagnosis is the center part of the radiator has become plugged not allowing air to flow through and heat the bi-metal in the fan clutch. I would like to add that my 89 300E has 156k on the odo, original fan clutch, same for the wife's 93 300E with 112k miles.

chowpit · #45 10-18-2002, 11:50 PM

Sorry for the late response on my last post.
BTW, the best way to test a fan clutch is to get the eng to operating temp, disconnect the aux fan and throw something over the grille to stop air flow. Run eng to approx 110C (approx 2,000 rpm). At some point in time the clutch should lock up and start to roar (moving air), uncover the grille and the fan should pull air through the radiator until it has cooled down. The roaring noise should fade as this occurs.