Overheating??? 1993 190e 2.6

[escarbor]

Hi folks,

I've got an overheating problem that occurs when I'm idling my 190e 2.6. I've flushed the cooling system and put a 50/50 mix of antifreeze and water. When I'm on the road the temp is just above 80 degrees centigrade. When I stop and let the car idle for just a few minutes the temp climbs to near 100 and sometimes higher. AC adds to the temp increase, but still only at idle. My aux fans work, but I've had to jiggle the relay a few times to have them come on. When the aux fans run it only helps a little bit. The heat works fine and the heater pump and core are ok I guess (the heat on obviously takes heat out of the system and the temp drops). Ever since I had the water pump replaced (3 months ago with genuine MB part) the overheating problem has been apparent. Now that summer temps are here, it's obviously getting worse. I also had smog pump replaced and in the process, my mechanic noticed leaking in the transmission fluid lines connecting to the radiator. The lines were replaced and he said one was a bit clogged and thought the overheating problem might have been caused by the blockage. That seemed a bit far-fetched to me. One thing I have not done is replaced those aux fan relays or replaced the thermostat. How can you tell if a thermostat is bad? Any suggestions? Also... how high a temp is too high? I've been told anything over 100 is really dangerous and can damge the engine. Anyone??? Beuller??? Beuller??

Any advice will be greatly appreciated.

Regards,

Ed[FONT=times new roman][COLOR=darkblue][B]

[euro 287]

100 degrees will not damage the engine , 115-120 will though. If you didnt replace thermostate when you did the water pump then that is one of the first things.Make sure to fill the upper radiator hose with water to before reconnecting. Make sure to warm the car up until you can watch by the needle on your temp gauge drop when the thermostate opens and then run the heater for a few minutes. You can also run your hand (with car off) down the front of the radiator and feel for cool spots. That would be clogged radiator. If it is half cold half warm then it could be thermostate or radiator (flow problem). Thermostate is cheap enough for the first thing.

You say your aux fans work, but does the main cooling fan kick in ok? (ive only got the one fan on my 190) it should kick in at 100 or so, then shut of at 90.

im sure the aux fans are only for the air con, not for cooling as such.

[joe p]

I'd look real hard at the radiator and fan clutch. Go ahead and do the t-sat and make sure you burp/purge the cooling system for air.


Joe

[Jim Anderson]

Mine started doing that, but it started on its own. I was scheduled for a coolant change and while I was at it changed the t-stat housing from plastic to metal and while I was at it change the t-stat. I turned out the t-stat had physically broken. Now everything is ducky.

BTW I didn't burb the system but everything works fine, maybe just thinking about it was enough.

Does your's have a plastic housing?

[John Plut]

I also would also suggest replacing the thermostat first. They do go bad. I just put a Wahler brand from Fastlane in my '88 260e and the temp holds steady at 84^, of course it hasn't been very warm here in Illinois yet. Another possibility is that you have air trapped in the cooling system. Thermostats are supposed to have a small jiggle valve that allows air to vent. Sometimes that valve gets corroded shut. That would explain why your problems started after your coolant was drained.

Good Luck.

[escarbor]

Thanks for all the replies. I replaced the thermostat and used a Volt Ohm Meter to test the high speed fan relay. It was smoked. The new one came with a 40 amp removable fuse. All is well, no more overheating. Thanks to everyone

Ed