My car runs fine on freeway but in stop n go traffic the temp. goes from 90c to 110c until the aux. fans switch on and bring it back down to 100c.
The process is repeated until I hit the highway and she's back to 90-95c.
I changed the cap,thermostate and coolant (50/50)mix and radiator is 1 year old.
My only suggestion from reading the forum is the viscous fan clutch.
A few tests have been done and the results were:

1-on start up in the morning I take it straight to 2000rpm and I can hear a loud howl for 20 secs then it goes away.

2-When turned off cold,the fan spins freely.

3-When turned off hot,fan spins freely(same as cold).

This leads me to believe that it's the VFC (no fluid).Am I right?
If so how much fluid shall I put in?

You cannot add fluid to the VFC. They come sealed from the factory. Once it's gone, it's gone.

Thanx for the quick reply,but do a search and you will find otherwise

There was a thread a while back on someone drilling a small hole in the fan clutch and re-filling it with fluid. It might work, but I'm sure its just a temporary fix.

A new one should cost about $100-$120

__________________
1987 mercedes 300E
1995 e320 conversion(hated the 300e grill)
HID/Xenon (D2S)
Keyless Entry
Monochromatic Paint (Custom Blue)
Smoked Tails
Flat Badged (front)
Debadged (rear)
custom "carbon fiber" console
18 inch HP EVO rims
Sold! Now I drive a Monte Carlo SS
http://memimage.cardomain.net/member.../352975_67.jpg
http://memimage.cardomain.net/member.../748335_24.jpg

First, never take the engine right to 2000 rpm stone cold, you have essentially no oil circulation and you will eventually ruin the bearings and cylinder walls. Wait 30 sec or so, and drive slowly for at least two blocks before exceeding 2000 rpm. The engine will last at least twice as long.

You almost certainly have a dead visco clutch. If it's covered with greasy dirt, it's dead for sure (that's the oil that is supposed to be inside).

The new one is pretty easy to install, you need an 8 mm Allen, a coathanger wire, and a few minutes. Pull the fan shroud clips, insert the allen into the center of the clutch, use the wire to trap the clutch from behind (should be a small slot in the bearing bracket), loosen allen, unscrew it (use both hands, it's tight in there!), remove clutch and fan complete. Unscrew fan from old coulth (10mm screws, I think), screw onto new clutch, install using the coat hanger to tighten. Very easy.

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

Psfred,it is covered with greasy dirt.
When engine is hot and I turn the car off the fan just free spins like when cold.Shouldnt it stop within 1 revolution?

I have read on the board that these fans can be filled with new fluid.???

The viscous clutch keys off radiator exit air and this seems to correlate well with a coolant temp of about 100C in warm weather. Once the fan clutch tightens I can hear distinctive "fan roar" begining at about 2000 revs.

This is my "test" for a properly functioning fan clutch. Get it hot enough (100C or a little over) to engage the viscous clutch, but not hot enough (about 105C) to engage the electric fan(s). Then listen for fan roar at about 2000 or above. If you hear it, the clutch is probably okay. If not, the viscous fan clutch is probably dead.

Duke