M119 is still running hot...What temp does yours run at? - Page 4 - PeachParts Mercedes-Benz Forum

mespe · #46 03-24-2007, 11:17 AM

I believe the fan clutch is used to allow the fan to NOT spin when the car is cruising at highway speeds. By not spinning at High speeds, less strain is put on the engine, as the amount of air passing through the radiator is greater then what the fan could possibly deliver.

Sorry to hear about the head gasket, usually head ghaskets go when a car is run hot, but there are other causes of this type failure as well. But there are usually other indications as well. A cooling system pressure test is the best way to check your cooling system. Just pressurize the cooling system and look for leaks. If the pressure doesn't drop, then you have no leaks, if the pressure drops then you have a leak. It will show you where the leak is. If the pressure drops and you don't see where the leak is, then it's usually internal.

I don't think the mirror on the exhaust is effective because one of the by-products of combustion (with a cat) is water. How are you supposed to differentiate this water from the steam caused by a leaking head gasket???

Pressure testing the system you will know for sure. Other symptoms of head gasket failure are 1) a/f in the oil (coffee - with cream - colored oil) or a/f boiling out of the cooling system. If the a/f is being sucked into the combustion chamber, a stop leak should help for awhile, provided the engine doesn't run too hot, but stop leak gets mixed reviews because of it clogging the cooling system.

david s poole · #47 03-24-2007, 11:51 AM

read the whole thread and have this question,have you checked the aux fans when running to make sure that they are running in the right direction? if not it would explain your whole issue.

Dcraig · #48 03-24-2007, 11:53 AM

When they are on, they do suck air into the engine.

david s poole · #49 03-24-2007, 11:59 AM

is the air getting thru the condensor and radiator and coming out by the engine fan?

Dcraig · #50 03-24-2007, 12:05 PM

Yes. If I put my hand behind the radiator, above the belt, there is a strong push of air.

But I am losing coolant, and I don't know where it's going. I've never let the temp go into the red and I don't see any dripping anywhere.

The thing that baffles me about the fan clutch is that it will come on and off when it wants to. I thought the oil inside reaches a set temp, then it'll engage. On my car. I activated the throttle from the engine compartment and could feel it engage, but when I let off the throttle, it would disengage. Even if I held the rpm's up, the fan would disengage.

DRICHFL · #51 03-27-2007, 01:10 AM

I had the same problem of losing coolant a few years back. It took me months to finally figure out where the leak was located. I suggest a radiator pressure check tool to check for leaks. The tool allow you to replace the expansion tank's cap with a modified cap so that you could pump pressure into the cooling system. After applying the pressure you may look around and find the leaking hose.

On my E420, the rubber hose that was leaking is located next to the brake booster. The rubber hose has a three way rubber connection that leaked from the bottom and the leak was not visible from the top. The coolant would leak out at the fender drain on the drivers side of the vehicle. The hose is prong to failure because of it three way mold design.

JimF · #52 03-27-2007, 02:51 AM

Quote:

Originally Posted by Dcraig

The thing that baffles me about the fan clutch is that it will come on and off when it wants to. I thought the oil inside reaches a set temp, then it'll engage.

On my car. I activated the throttle from the engine compartment and could feel it engage, but when I let off the throttle, it would disengage. Even if I held the rpm's up, the fan would disengage.

If you are talking about the "vfc" then it operates when the bimetallic strip (bms) gets enough bend to activate the 'pin' clutch that release the silicone gel into a chamber that locks in the fan. Read Menu#20 for more info on how it operates.

It disengages with high rpm, around 2500rpm on the tach independent of temp. It does that b/c the fan is not needed due to the high road speed which forces air into the rad and engine.

Re 'leaking hoses'; if that was the problem you should have seen some coolant on the ground or on the garage floor by now.

atspeed · #53 07-15-2007, 12:33 AM

DCraig,

Any news about your E420? I just bought a 1994 E420 and noticed, while it stays cool enough in 90F weather, the fan clutch doesn't spin freely when cold, and that there is some kind of thread wound behind the clutch and jammed between the pulley. This may have been the previous owners cheap fix for an old fan clutch, but it surely isn't a permanent fix.

Pete Geither · #54 07-15-2007, 08:42 AM

Just sat and read this whole thread, and thought, this is what I just went through. Turned out to be a wire to the resistor right behind the drivers headlight was corroded and had a bad connection. Found out about this from another recent thread about A/C pressures causing the fans to come on. The fans on the 400E were running a LOT on high speed which they never seemed to do before, and the temps were routinely going over 100. Check that resistor.
Here is that thread.
http://www.peachparts.com/shopforum/showthread.php?t=193757

Dcraig · #55 07-17-2007, 11:13 AM

Sorry for the late post....

My E420 had 2 leaking radiator hoses. They were so slight that they never made any drips on the ground. My mechanic found then and fixed then, so now the coolant is holding steady.

As far as the coolant temp, it still seems high. For the first 20 minutes of driving the needle will stay just above 80, then it will go up to 90 and fluctuate between 110 to 100. Sunday in Palm Springs (over 100 degrees) the temp went past 110 to about 115, but I was in stop and go with the AC on full blast.

I still don't trust the VSC. I should have spent the $650 for the real MB part and the extra money for a real MB-Behr radiator instead of the cheaper Behr without the MB logo. My mechanic seems to think MB keeps the best Behr radiators to put their logo on.

From now on, it's all real MB parts for my car, no OEM.

Craig