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87 190e 2.6 Cooling System questions

1199 Views 6 Replies 4 Participants Last post by  Nate
I have an overheating problem that I can't seem to find. It overheats, to the red area of the gage after climbing hills for 2-3 minutes or long freeway driving times, 1/2 hour or so. Also in traffic on a hot day, 90degrees plus. I had the radiator rebuilt and it has a new thermostat. Here are my questions:
1) Should the aux coolant pump be running all of the time, if not when should it it run? Does it have a sending unit, temp switch, etc
2) the main fan behing the radiatior doesn't ever seem to lock up. what temp should it engage and are all of these electrically controlled. A mechanic told me that some of these are mechanically locked with some kind of wax ring. ??? Does anyone know for sure if all models of 87 190e 2.6 are electric or mechanical. If electric where is the sensor located?
3) The electric fans seem to be working fine
Thanks in advance for your help.

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That sounds like an aux cooling fan (the big belt driven one). What usually goes is the...

That sounds like an aux cooling fan (the big belt driven one). What usually goes is the clutch. I think mine may be bad, but I don't ever come close to overheating so I'm not worried right now.

Aux coolant pump is solely for the climate control. At least that's my understanding. If it's a dealer thermostat it may be bad, those usually have problems. Don't know why. Those ones you get at autozone seem to be better for some reason.

The sensors (not positive on which does what) are at the two ends of engine. So one on the water pump at the bottom, and one on the top. You will see where the hoze goes into the engine there's a wire comming off the sensor.
 

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1996 Stang, 1995Jeep
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Overheating

the large belt driven fan (white) is your main fan. It should kick in at about 110C. it's controlled (just like your aux fans) with an electric switch on top of the engine where your upper hose is connected. the electromagnetic clutch VERY RARELY goes bad (no moving parts). Check your switch first ($21.00 from a dealer). I had the same problem, plus the new switch was bad too, which threw me in a loop. DO NOT lock in the main fan pysically, because it has a limited max RPM. If your drive belt runs too fast, the fan may just fly apart (you REALLY do not want this). Overheating during driving has nothing to do with the fans (at 55mph the air flow is WAY higher than anything produced by a fan). Look elswhere. Top choices:
1) rebuilt radiator is plugged
2) your water pump is going
3) your head gasket is gone (any persisting oil leaks??)

My bet is on the radiator. Also, turn off the AC and see what happens.
 

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Discussion Starter · #4 ·
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Last night i drove the car about 50 miles up into the mountains and absolutely no overheating. this morning I got into the car dove about 5 miles and it went right to the red and stayed there and wouldn't come down no matter what I did and the radiator was not hot but everything else was hot. Somehow water is not getting into the rad at times and is getting in at other times. I am puzzled.
 

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That's a thermostat problem. It's not opening all the time. Did you replace with a dea...

That's a thermostat problem. It's not opening all the time. Did you replace with a dealer t-stat? If you did, go to the autoparts store and get one there. Don't know why the dealer ones are so faulty.
 

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1985 190E 2.3
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Nate, I thought the aux fan is the smaller one in front of the radiator, the electric dr...

Nate, I thought the aux fan is the smaller one in front of the radiator, the electric driven one, and the main one is the belt driven one with the magnetic clutch. Is this about right or did I or someone else get something mixed up here?
 
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