W108 overheating
 

Hi,
My 69 280se m130 slowly heats up if I let the car sit and idle or in traffic. I'm trying to debug this problem. I feel some resistance with the fan clutch, but don't know if it is correct. The electric fan never turns on. I applied 12 V to the fan and it worked, but the current draw was a bit over 12 Amps -150 Watts!!!!!! Is that correct? No noises. Does it need to be lubed!. I'm assuming there is a resistor and a relay involved in powering up the fan. I don't have a wiring diagram.

Can someone help me locate the resistor, relay and whatever temp switch is supposed to trigger the fan? Turning on the AC doesn't make the electric fan come on either.
Thanks,
Narayan

Sounds like the fan clutch. With the hood open, you should be able to se the fan. Shut off the engine. The fan should start just about immediately. Do this with the engine hot or at running temperature.

Thanks,

David

You can test the fan clutch w a rolled up newspaper. If you can stop the fan with it, the clutch should be replaced.

It's almost a 100F day here. Yesterday I replaced the fan clutch. It was toast. I also added redline water wetter. It still slowly creeps up, slower than before... I found a fan shroud on ebay. I'm waiting for it to get here so I can try it on. If that doesn't work the next step is redoing the radiator.

The temp switch was toast. With a new temp switch, the electric fan comes on now. BUT, I stripped the mounting screw holes in the fan's aluminum housing and haven't been able to mount it on the car.

Would an electric fan from a w123 or w116 bolt on in front of the ac condenser? Anyone tried this? On a positive note, I took the 280se on a 100mile roadtrip this morning. It used about 5.3 gallons --->19+mpg. That was with liberal full throttle use. I average 12.5mpg around town/mixed!
Narayan

Electric fan has been mounted. No more overheating!!!! Thanks to all those who responded -posts and PM.

Please tell us which fan did you used? and how did you install it?

maybe somebody will benefit from the thread ... and pming nullifies this purpose.

I just reused the OE fan. I drilled out the stripped threads and used a larger self tapping screw/bolt. My fan shroud arrived. I'll install it this weekend. This has been a mild summer so far. It's mostly below 90.

I don't see the problem with people giving me ideas via PMs. Some people don't want to post as even though this forum is much more civil than most, given the age of our cars and our average age and hopefully the maturity that goes with it, occasionally pissing contests do occur.
Narayan

:thumbsup:

I never considered it that way; I always thought PMs were for something personal or private information.

For sure, to people like me trying to learn by reading experiences on how to solve problems and recomendations is priceless.

Not to derail the overheating thread much, but...

Much of what we all share is based on experience and opinion, and sometimes the differences aren't accepted, hence some will rather share theirs via PM to save the thread from the inevitable fallout. :confused:

"Opinions are like a--holes. Everyone has one, and they all stink."

:P

As an example, I personally won't post in threads where people are having trouble with their points-based forty year old distributors when I have found a modern solution to it all, but will PM them my experience and opinion instead since that experience and opinion inevitably raises the hackles of folks who think the solution is "too expensive". (In my opinion, a few breakdowns or a tow truck experience due to points failures justify the cost right there) I accept that like Nero, those folks are happy to fiddle away with their points and old distributors. LOL

It was almost 100F today. I have the fan shroud on and still no overheating!!!! I got a lower temp (79C) thermostat that I may not need to install. Lucky for me because it looks like the AC compressor and bracket need to be removed to replace the thermostat! Does anyone know any short cuts?

Awesome. The shroud does make a big difference.

Yes. Will send you a PM. :D

I'm not sure if yours has an oil cooler, if it does, make sure it's doing its job. I recently replaced the heater core on my 1970 280SE, which had been cooked due to a higher-temp thermostat installed eons ago, the oil cooler lines disconnected at the oil filter housing, and a once-faulty fan circuit. Everything's now in working order, new heater core and oil cooler fabricated from scratch, lower-temp thermostat, and new MB hoses and pipes reconnected.

There's an oil cooler that is adjacent to the left side of the radiator, but it really isn't in an active stream of air while the car isn't moving.

I'm sure it helps some, as in better than not having it, but it isn't an optimal setup, compared to external coolers that have a fan or are in some good air flow.

Sorry to dredge up an old thread but what fan shroud did you use? I was under the impression that only the V8 models came with them. Will that work? I've been looking at Part# 1085050255.