190 E 2.6 overheating - PeachParts Mercedes-Benz Forum

dan rawlings · #1 03-24-2008, 03:58 PM

This is a 1989 car with 180,000 miles on it. Runs fine, but engine temp rises immediately in traffic and at stop light. Water pump and thermostat has been replaced, radiator flushed and new coolant.

The normal temp appears to be about 89 degress. It climbes to 95+ immediately when stopped.

The driver side aux fan runs fast when plugged into 12V, but the passenger side aux fan does not. Also the dirver side fan does not turn on ever, unless I am testing it.

I am not a mechanic. I'd like to know how to determin the problem. Temperature sensor, relay, do I need both aux fans working.

A new fan form MB is $340, relay $27 and sensor $35. Can you tell me how to test, where the replay and sensors are, what they look like.

The parts at this site cost less, but MB tells me not to buy anything but BM for this car. I am reluctant, but presume these parts are OK. Are they OK?

Obviously I am a novice to MB, but no idiot under the hood.

Thanks.

Dan

david s poole · #2 03-24-2008, 04:15 PM

sounds like your fan clutch is not locking up and needs replacing.you will need the aux fans when running the a/c at 100deg f or more but not at 75deg.other poss is radiator tubes shrunk[they are aluminum and do this].try speeding up the engine in neutral[about 2500rpm]and see if temp gauge comes down,if not replace the fan clutch.

tvpierce · #3 03-24-2008, 09:47 PM

Quote:

Originally Posted by dan rawlings

The normal temp appears to be about 89 degress. It climbes to 95+ immediately when stopped.

You say 95+ degrees... how much more than 95?

My fan clutch doesn't even engage until 100 degrees -- and I believe that's normal. Am I correct David?

So while driving/in motion, I'm normally at about 80-85. When I stop for more than 60 seconds, the temp starts rising. After an additional 2-3 minutes, it will reach 100 degrees, at which time the fan clutch engages, and maintains the temp at about 100 degrees. (I have a new radiator, water pump, all new hoses, and new thermostat) This is how mine has acted both before and after I changed the above mentioned cooling system parts.

(WARNING -- THE FOLLOWING IS ONE OF MY SOAP BOX RANTS): Personally, I feel that this "acceptable" range is , well, unacceptable. The way I see it, if the engine is designed to run at 100 degrees, then spec a 98 degree thermostat for it -- not 87 degrees. If it's designed to run at 87 degrees, then spec a 90 degree thermal switch to activate the fan clutch sooner. I mean good heavens, 15-20 degrees of differential??? C'mon... it's an MB, not a John Deere tractor.
(END OF SOAP BOX RANT) Halleluiah, holy crap! Where's the Tylenol?

Arthur Dalton · #4 03-24-2008, 10:27 PM

Is that with ac on ???

fouskos · #5 03-25-2008, 01:32 AM

Change the fun clutch and you will have a constant 87C.
It is a 10 min job.

david s poole · #6 03-25-2008, 09:29 AM

i think you guys are mixing up the 2.3 and the 2.6.the four banger has an electric clutch[switched by sensor and heaven help if sensor goes bad]the six cylinder has normal bi-metallic fan clutch.i was of course speaking of ambient temps not engine.

dan rawlings · #7 03-25-2008, 01:21 PM

The numbers are without the AC on. I don't know if I have ever gotten to 100 degrees since I replace the thermostat. Based on what I am seeing in the posts, I am not sure even if I have a problem. I find it disconcerting to have temp rise when I am stopped and the weather is cool.

Again, I don;t think I have ever seen/heard the aux fans engage, so I am thinking something is ary.

Arthur Dalton · #8 03-25-2008, 01:57 PM

Well, the fans are wired together, so you have a basic problem with one of them.
They are supposed to run at low speed with the a/c and high speed at 105C coolant temp.
There are 2 easy test for circuit verification..
Key ON..
Jumper pigtail wires at the pressure switch at the a/c drier..that should give you LOW fans..

Pull connector off blu 2 wire sensor at thermo housing..that should give you HIGH fans

Report findings

dan rawlings · #9 03-31-2008, 11:52 AM

The car has been at a shop for another matter. I do not have the tools to fix this problem, but I do like to research the problems as I grew up working on old cars.
This particular problem has turned out to be a combination of problems. The fluid clutch on the main fan was failing. Also one of the two aux fans (passenger side) was completely dead, the other ran OK when connected to 12 V.

The mechanic told me he was probably going to remove the radiatior to fix the fan clutch so it might be a good time to replace the dead aux fan. I have not evaluated the relay or the sensor 1) since it was already at the shop and 2) because me and my $2 volt ohm meter do not get along.

Thank you for the advise.

One more thing. Any of you know how to solve when my wife tells me the car is a money pit......again? Come on sages.

I do not agree, it provide good service. I bought it cheap and have had to repair/replace several maintenence-level issues.

Dan

Ivanerrol · #10 03-31-2008, 06:27 PM

A competent MB mechanic should not need to completely remove the radiator to replace the fan clutch. The radiator can be moved to the side a little to do this job. Only take twenty minutes.

A sage may say : "No such thing as a cheap Mercedes". (or your wife may be correct.)

A well maintained MB may last a lifetime, A neglected one.......money pit.

costanza · #11 04-01-2008, 09:36 AM

Quote:

Originally Posted by Arthur Dalton

Well, the fans are wired together, so you have a basic problem with one of them.
They are supposed to run at low speed with the a/c and high speed at 105C coolant temp.
There are 2 easy test for circuit verification..
Key ON..
Jumper pigtail wires at the pressure switch at the a/c drier..that should give you LOW fans..

Pull connector off blu 2 wire sensor at thermo housing..that should give you HIGH fans

Report findings

I REALLY need to check this on a 2.6 190E I'm refurishing! Can you post pics of the pressure switch on the AC drier and the sensor on the thermostat? If not, I can take pics of the general areas on my engine and you could point out the correct test points.

THANKS!