Now that the weather is colder it seems my 400e is running cooler than it should. The temp gage doesnt make it to 80?

History on the car. I've owned it for less than 1 year. I replaced the radiator this spring when the viscous fan clutch self distructed and ate the radiator. Everything ran fine in the summer - on extremly hot days (90+) I got some coolant blow off after stopping (I believe I need a new expansion tank since the neck moves slightly when you take the cap off).

In changing the radiator I found the plastic fan shroud was broken, the right hand side of the lower half was snapped. I did not replace this. How much more cooling in cold weather do you get with airflow through the whole radiator? I also have not put the underbody panel back on which may also raise the temp some.

Any experience with a M119 engine running to cool (there is lots of info on to hot).

Thanks
Paul
1992 400E
1984 300SD

I would check the thermostat and replace pronto. They are only $10-$15.

In hindsight, my thermostat on my 1991 300CE (W124, M104) was faltering, i.e. staying open, resulting in low running temperatures around 80C. It finally failed, in the closed position and I overheated.

glenmore
1991 300CE
1990 LS400

My engine was also running to cool when going on highways, changed the thermostat and now everything is fine!

Same experience here with a thermostat failed in the open position.
I replaced it before it failed closed. 1/2 hour of my time to replace (and I took my time)

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1999 Porsche 996 Carrera Convertible
1994 420E - SOLD
1986 300E - SOLD, what a car
609 Certified

Replace thermostat, this will cure the overcooling problem (and prevent overheating if it fails shut, too!).

Replace the fan shroud and re-install the sound encapsulation panel -- both these items are important to provide proper cooling air flow in hot conditions. the fan shroud is designed so that the fan will pull air over the entire radiator and exhaust it. Without the shroud, air will circulate from behind the fan around the to front and back again, rather than through the radiator. You then risk overheating.

The bottom panel has a vent slot in it, aligned with the shroud and fan to exhaust the hot air out the bottom of the engine compartment rather than back over the engine and firewall. Helps keep both engine and passenger compartment cooler, and keeps water off the alternator and belt, too.

Peter

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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!

I've got the same exact situation about the car running colder with the beginning of colder weather.
cold running, poor heating (searched already)

if someone has some other suggestions that would be great.

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Whether you think you can or cannot, Either way you're right!. by Henry Ford.