My 260e runs fine temp while driving but when I stop at a light or in traffic it starts to over heat, once it almost hit 120C what do I need replaced. I recently had a massive collant leak and dumped in some radiator sealer. IS there a blockage or is the thermostat broken? Please help

Sounds like a fan problem.
Can you verify that the aux fan (in front of the radiator) is running by the time you hit 110°C?

__________________
-Marty

1986 300E 220,000 miles+ transmission impossible
(Now waiting under a bridge in order to become one)

Reading your M103 duty cycle:
http://www.peachparts.com/shopforum/831799-post13.html
http://www.peachparts.com/shopforum/831807-post14.html

If your t-stat were an issue it would run hot all the time. The radiator sealer combined with existing corrosion/age in the radiator may be impeding flow. It's not as bad on the open road because of the increased air flow.

Either replace the radiator or have the old one rebuilt. If it's old, skip the rebuild and get a new one. You might want to flush out your system as best as possible when doing the radiator work. The sealer has intermixed with the coolant and is now everywhere.

It's been my experience that the original dark colored, pellet Bars Leak was pretty good in some cases. The newer Alumina silver formula is pure muck and likely to plug up your cooling system. Don't ask how I know this.

__________________
Mike Murrell
1991 300-SEL - Model 126
M103 - SOHC
"Fräulein"

update!
Myu car is dead. I got on the highway after work and hit 120C. I immezditly pulled over and tried to get off the higway. MY ran at 120C driving or not so I think the WP is dead. I hope the head gasket survived, the temp hit the red for maybe 3min but was at 120C for maybe5 or 10. To top it off, i locked the car with the keys in the ignition and my keyless entry is non working so my car is in some neigbohood with the keys init. Hope it doesnt get stolen. Its goin to the shop tmrw, what will the water pump replacemnt cost on average? Any thing else to get changed while its in. Thanks
Ben

How do you know the water pump is dead? How do you know that your radiator isn't plugged up?

__________________
Mike Murrell
1991 300-SEL - Model 126
M103 - SOHC
"Fräulein"

A defective water pump very seldom cause overheating. Normally, when a water pump fails, it leaks.
I would suspect an other source for your problem.
A failed thermostat (closed)
A plugged radiator.
Could be as simple as a defective temperature sending unit.

Maybe just have the whole cooling system replaced.


Have them pressure test the system for leaks first and change the thermostat.
Also do flush the system and change coolant (use MB or recomended coolant please).

What was leaking that caused you to add the leak stopper?
Sounds like you might have some cooling issues (plural).

__________________
-Marty

1986 300E 220,000 miles+ transmission impossible
(Now waiting under a bridge in order to become one)

Reading your M103 duty cycle:
http://www.peachparts.com/shopforum/831799-post13.html
http://www.peachparts.com/shopforum/831807-post14.html

That's where I'd start. Try supplying the fans w/ power directly from the battery to see if they run. If they do, you'll have to replace a little sensor.

__________________
1990 190e 2.6 - The only one I can really call "My Car".

1987 190e 2.3 - The donor car's up and running, only mods are Euros and a Sony headunit. My Dad's runabout now.

1990 300e 2.6 - The parents' ride.