Overheating Diesel? - Page 3 - PeachParts Mercedes-Benz Forum

84300DT · #31 04-06-2003, 09:12 PM

Quote:

Originally posted by psfred
The easy way to test for the presence of a coolant temp fan switch is to pull that wire off the thermostat housing and ground it with the key switch on. If it is a fan switch, the fan will come on.

Peter

looking at it i think if i pulled the wire off that connection on my car it would prolly disintegrate forthwith so i think i will leave the sleeping dog alone..lol

Deezl · #32 05-03-2005, 11:32 PM

Quote:

Originally Posted by rmmagow

When I first bought my 83 300D last June or so it ran at a very steady 90C on the guage. This past winter it would occasionally get within about a needle's width of 100C. Usually turning the heat up would make it go down again. Today it started running a bit warm again, this time about a needle's width above 100C. Cranking the heat up all the way would drop it back down some. When I got home I let it idle in the driveway while popping the hood to have a look-see and the temp dropped back to normal, about 90C. Someone told me they heard a belt squealing when I started it up the other day at work. Anyway, some questions, the electric fan in the front, is that supposed to come on even if the A/C system doesn't work? What temp roughly should it come on at. Could a little belt slippage cause it to go up like this ? Maybe it slips a lot at higher engine speeds? I'm going to put in 4 new belts this weekend. No drop in fluid levels and no dripping anti freeze in the d'way. Can someone confirm for me that 100C isn't all that too hot for this engine? Regardless, it still runs well and hopefully it's just some maintenance being needed.

RMMAGOW,

My '83 300 D with 142K miles, is experiencing these same symptoms. What fix did you employ?

Thanks in advance,

Deezl

rmmagow · #33 05-04-2005, 08:30 PM

Hi,
Hate to say it, I've just been living with it. 15K miles since I wrote that note and nothing's happened. My plan is to replace the thermostat and the water pump (after having the radiator checked out), but in truth the car will probably be sold before I bother with any of it. I am pretty sure it is really running hot, but I think 100C just isn't hot enough to hurt these engines. In fact, I do own two of these, the one that runs in the 90C range all the time gets about 25 MPG, the hot one is doing 30 regularly. They are both 83's, one coupe, one sedan so very close to being the same.

bullwinkle · #34 05-04-2005, 08:47 PM

I have an '82, which I believe is the same as an '83-the aux fan ONLY comes on by the thermostatic switch at th A/C dryer-mine was bad when I bought the car and almost took out the A/C compressor(it rattles now when running bt miraculously doesn't leak and still cools OK). I would bet on the fan clutch, plugged radiator, possible temperature sending unit(mine reads around 100 C all the time and it's nowhere near that hot)-one good test would to try stop and go driving temps and compare them with high speed driving-a bad radiator would increase temps the faster you went, while the leaky fan clutch would cause higher temps in stop and go driving. The fan clutch can be refilled with fluid from Toyota(do a search).

Deezl · #35 05-04-2005, 09:32 PM

RMMAGOW and Bullwinkle,

Thanks for your responses.