Temperature guage has numbers at 80 and 120 and a line between which I presume is 100 degrees C. So the spaces between those marks must be 90 and 110.

Putting around town on a 50 degree F day at 30 mph max, the guage goes to 110 at red lights dropping to 90 when traffic flows. Observation while parked, the fans don't turn on (both work) until the temp guage indicates 110...quickly bringing the temp down to 90. NORMAL????

I have tried to remove the overflow tank cap soas to add fluid to the tank while the engine is running and guage is at 90 or above. Attempting to removing the cap (1/8 turn or less) results in scarry scalding volcano situation. Is the overflow tank supposed to be under pressure when the engine is running? Is one supposed to wait 30 minutes before doing adding water? NORMAL ???

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1993 MB190e 104k

So the temperature spikes when your sitting at a stoplight and the temperature goes DOWN when your in motion, right?

Sounds like a bad viscous fan clutch.

Actually I had a motorhome with a bad clutch once and only way to know was to replace it...no way to tell spinning from slipping.

Thanks, I will have a look in that direction.

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1993 MB190e 104k

Do not try to add water or coolant while the engine is running or hot. You will only risk hurting you and the car. You only add fluid in this way after a system flush wherein you leave the cap off after refill and keep filling as the thermostat opens.

The fact that your aux fan goes on tells me your temp gauge is probably accurate (the first question to ask in my opinion,) The three most likely components related to cooling are the thermostat, viscous fan clutch, and radiator. Thermostats sometimes fail, radiators get clogged, and fan clutches wear out. There are threads here (use the search tool on the website) to learn more about replacement of each. For a different car, 1984 380sl 107 series car, I wrote DIY notes on all of this. See threads started by me, click on ericgr.

Not true - there is "the carrot test". Scroll down to the 4th post in the thread.... usual disclaimers apply. If you are not confident / capable, get a qualified mechanic to perform any engine related work.

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Osteopornosis - A Degenerate Disease

You have all been most helpful. I am now searching eBay for a 'Certified DIN carrot'. Friend of mine prefers using a leather glove and sticking his finger into the blade. I prefer changing suspect parts until the problem goes away. But I can't see well enough to man a wrench anymore (is that sexist?).

Again, thanks all, and thanks Mr. MB Forum for being here.

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1993 MB190e 104k

Paul,

Glad you found that as amusing as I did . I have actually done this on my own car - finally overheating traced to failed waterpump (she was losing water). Hope you manage to sort your car out.

Regards,

P.

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Osteopornosis - A Degenerate Disease

Is this a 2.3 or 2.6? If its a 2.3 the big fan is an electro magnectic fan controlled by the fan switch on the head.