OK guys, thanks to all of your advice I have been working dillegently (sp?) to find the cause of my 190E overheating. We had narrowed it down to the fan clutch, since while the fan kicks on, I discovered accidently that if I just barely touched it, it would instantly stop moving. We figured the clutch therefor was shot, and so replaced it.

Well... It's still overheating. Not only that, but the fan STILL stops if you just barely touch it (like, if you drop a towel against it)

There aren't any clogs in the radiator and the water pump appears to be working perfectly clear.

I'm stumped!!!! I replaced the fan clutch in about an hour and put everything back together SURE that I had fixed the problem (Even tho I rigged a tool out of a bent and filed peice of metal, electrical tape, a hose from a WD40 can and the handle from a rake to stabalize and removethe fan clutch bolt instead of buying the mercedes tool LOL.. but hey it worked like a charm!) but started it back up and in 20 minutes I was overheating again.

*SIGH* any more words of advice???

 

Hey Redwolf,
I'll try to help you, but then you can help me too.

Which of the following things have you NOT checked?

Coolant level
Did you "burp" the air bubble out of the thermostadt housing
thermostadt installed "right side up" not upside down.
thermostadt working properly
Water pump pully spins freely
Impellers on water pump in tact
Fan switch, fans

Fuel octane
Fuel pump pressure
fuel pump volume
fuel injector spray pattern
fuel/air mixture adjustment
tear in the air meter boot
loose or broken air/idel valve hoses
loose or leaking vaccum lines
loose or leaking EGR pipe


Blue

Oh, would you mind looking at your engine and telling me where these vacuum fittings are supposed to connect. I marked them 1-4 on the photo attached.

thanks Blue

[IMG]local://upfiles/10968/9AB17A61B4A74AB08917733E152F933F.jpg[/IMG]

 

I've checked everything but the impellers on the water pump with nothing found-I'm going to go read up on the water pump and go back out and check the impellers when I get home.

Now on the fans, the main fain still stops at the slightest touch, and the aux fans don't cut on until it hits 100C- is that normal? I figured the aux fans would activate a lot sooner. I have to get back to you on the engine as I am not currently with my car but I will let you know ASAP on the vaccum fittings.

Thanks so much for the image!

 

Hi Redwolf,

Yes, the main fan is supposed to stop by hand. This is the purpose of the fan clutch; it is a safety device. It keeps you from losing a finger. In the old days before fan clutches,vibrationwould fatigue the fan shaft until it snapped, and in some cases a 4000rpm metal fan would slice through the hood and become air-bourne. Henceforth, plastic fan and a clutch.

100degC is approximately normal for the aux fans. If they came on any sooner they would drain the battery down; they use a tremendous amout of electricity. It sounds like they are working. Usually when they break, they either do not come on OR never shut off.

Honestly, checking the impeller is a last resort. Pump impellers can bedisintergrated by"air-cavitation". This occurs when air bubbles are drawn into the pump through a leak. The air bubbles cause the impeller to "slap"the water like a paddlewheel rather than run in a smooth fluid manner. The slaping and theair abrasion can wear theimpeller blades orbreak them off completely. fyi

Did you know that my rubber meter boot cracked once, and the engine ran so hot that the exhaust manifoldsglowed orange in the dark like a foundry. I didn't even need a flashlight! And this was with a perfectly good cooling system, so I'm still thinking you have an "air-intake leak" somewhere. I'm concerned that you are still having an overheat problem; these cars are tricky.

Blue

 

On my car, a friend had driven it for about four years, and for some reason he or his mechanic removed the vacuum hoses. He lives deeper in the mountains than I do; I guess they were trying to repair the car. Anyway, I want everything exactly the way it was, now that I have the car back.

Blue