I am at my wits end with this car. Two weeks ago, my car was massively overheating. I had poured two bottles of coolant in 28 hours, and the car sprayed all of it all over the road. It was running at 115-120 degrees. So, I took it in and my mechanic said the fan clutch broke. So.. three hundred fifty-eight dollars later, I get my car back.

Now, It's July 16. It was 96 degrees fahrenheit outside. I drove about twelve miles in stop and go traffic. The car hit 110, and instead of leveling out and going down, it continued to go up. it hit 120, and then went into the stratosphere at 135 or 140.

I stopped at my house, and opened the hood to look at what was going on. the electric fans werent turning. I turned the car off, and the main fan freewheeled for a second and then stopped, but the car made the telltale signs of the fan clutch working properly every time the car passed 100. Does the fan clutch just break at high temperature?

For most of the day, the car ran in the nineties and around 100. Then.. this.

What is wrong with my vehicle? Do I need to flush coolant? new auxiliary fans?




Thanks,
Chris

Do the cheap, easy stuff first... Coolant flush (Zerez GP05) no green stuff, and a new thermostat if you can't remember when yours was last changed...

Check all the fittings and hoses to make sure they are tight. Make sure to purge the system of air...

You could have radiator blockage due to a current or past head gasket leak. A new radiator for your car is an easy do-it-yourself project.

Your fans should be coming on, try a search on this forum for the aux fans and you'll find lots of information on how to troubleshoot them...

Sounds like there may be more than just 1 factor causing the overheating situation with your car...

-GH

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For Now:
1992 Mercedes Benz 500SL
1998 BMW 528i
2003 Honda Element
2002 CBR600F4i
1977 Coachmen Motor Home

First check is aux fan.

Test # 1:
Turn key ON, pull the connector off the blue/2 wire sensor at thermo housing.

Does Fan come ON high??

If no, then check fuse on top of fan relay [ behind fuse panel]

__________________
A Dalton

Listen to the man, Arthur will take you down the trouble shooting path, and things will be all right.

We are so fortunate to have the exchange of knowledge on this forum, you have no idea how much grief this can save you. Read, learn and absorb, its a great lesson on life.

Martin Wolf

If you do a coolant flush, open the block drain and get as much crud out as you can. There are some good posts on here about the different flushes to use. You could try pulling the thermostat and see if the car runs cooler or not. Good Luck.

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If it ain't broke take it apart and find out why.

1983 300SD, 4 speed
1994 C280
1987 300TD wagon
1996 HD Road King

Ride in Peace Eric Peterson, Harley of Macon

Indeed. the Arthur Dalton code reader is the best $15.69 I've ever spent on an automobile.

Alright, I pulled the connector with the two wires (red and blue) off and put it back on the blue side. Nothing. So, I pulled the green 30 amp fuse from the relay. it was broken. I put in a replacement. THe car ran cool, then jumped from 80 to 120 in two minutes. Then, it dropped from 120 to 100 suddenly and leveled off at 110. I looked to see if the aux fans were running, they weren't. I drove around to get it up to 120 again to see if it would repeat its little trick. It didn't. after a while, it got up to 120 and stayed. Lucky for me that home was less than a mile away. The car wasn't making that "roar" at 100 when the fan clutch is supposed to come on either.. I just had that fixed.

Could that connector be on backwards? Could it be as simple as corrosion on the red aux fan fuse?


And it is still boiling out coolant.

I have some radiator cleaner stuff. I'll run by the MB dealer and buy a new radiator cap and some MB coolant and hopefully flush it tomorrow.

ted:

This is my only car. Being carless is a big drag for me... I'm 19 and in college. I got this car on the premise of its legendary reliability. So far I've replaced a wiper motor, outer tie rods, plugs and wires, and a fan clutch. It's starting to sound like the other three vehicles I've owned. And that makes me sad. This one is by far my favorite.

What does that mean???
Put it on the blu SIDE ?? what is that???

And did the fan run after the fuse replacement??

How about some info back to me ...like

Do you have aux fan now ...YES or NO ..

__________________
A Dalton

I connected the red side of the red/blue connector. (That's the way I interpreted the instructions)

I had NO fan with it unplugged completely.

I replaced the green 30 amp fuse - NO fan afterwards.

OK

You are not on the same page , so I will tone it down..

You see this part??

http://catalog.worldpac.com/mercedesshop/sophio/wizard.jsp?partner=mercedesshop&clientid=catalog.mercedesshop&baseurl=http://catalog.peachparts.com/&cookieid=2EI1B4MYE2F21F3QIA&year=1994&make=MB&model=E-320-001&category=R&part=A%2FC+ACC+Temp+Sensor

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A Dalton

Yes.

that's the one from which I unplugged the connector

OK

Key ON , unplugged sesnor , and no aux fan...correct?

If yes..then go look again at that 30 A fuse on top of the green relay..see if it blew again.

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A Dalton

Ok. I will do that.

Even though I may be really slow, I do appreciate your help.

Don't worry..we just slow it down for ya...

That is why I show pictures of the parts...I hate typing.

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A Dalton

Thank you.

I have tried again, key ON, aforementioned connector unplugged. NO fan.

The 30 amp fuse has blown.

OK

Spin each fan by hand from the hub of the fans..see if they both turn equally free ..they should spin freely...if YES, continue on ..if NO, we have a bad fan motor [ drawing excess amps due to binding bearings and blowing the fuse]

Look for this part behind the drivers side headlamp area

http://catalog.worldpac.com/mercedesshop/sophio/image.jsp?title=Aux.%20Fan%20Resistor&url=http%3A//img.eautopartscatalog.com/live/G504051927BER.JPG

see if there are any burnt wires/connectorsa on these terminal.

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A Dalton