190e 2.6 running hot a idle......is it a waterpump issue?

Since the Temperature here is now around 80-85 I notice that the indicated temperatue creeps up whenever the car is subjected to long periods of idling
at traffic lights with the AC on. Taking it out of gear and revving it up slightly to about 1200 rpm brings the temperature down right away untill the high speed fan cuts off. Both fans appears to be coming on as they should. I m thinking that the water pump might be worn and not putting out much flow at the low rpm. Or could the viscous fan clutch be the culprit ? Any ideas? Thanks Peter
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If it doesn't go above 110c then it's ok. That is the temperature at which the crank fan should kick in and stop the climb of the temperature.
It is also possible that the pump isn't fully efficient, but in my 1986 190e, in the temperatures you describe, with a one year old water pump, the temp will go higher then the normal 80c while idling.
Marty
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The temperature will creep up to about 120 C untill I get nervous and put it in neutral and rev it up to about 1200 rpm. The high speed fan mode cuts in about 105C but the temperature still creeps up. Peter
said:

indicated
idling
up
the
should. I

flow
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Ok, that's bad. Some thoughts
1) Verify Proper coolant level 2) Perhaps the thermostat isn't coming fully open? 3) Is the coolant recent? 4) Radiator could be partially blocked, flush and fill.
When the Fan comes on the temp should stop climbing and in my car bounces from 110c to about 105.
I have read about some waterpumps that have damaged impeller "fins", but that seems unlikely.
I think that the thermostat is the logical place to start assuming the coolant is new and full.
it's quite normal for reving the engine to increase the cooling, and it doesn't indicate anything in itself.
Let us know what you find. marty
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Also clean your radiator fins with air or water.
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Radiator fins may be corroded, and the radiator cooling capacity therefor reduced.
I had that problem, and replacing the radiator immediately solved the problem.
(actually, I have had it on two cars)
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If all these suggestions do not cure your problem, use a vacumm gauge ,and see if you may have a head gasket on its way out.Exhaust sweet smelling? As a reminder,when the engine runs hot, so does your transmission.Radiator hot,so is transmission fluid! My advice is address the problem before you have bigger and more costly repairs!
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