Mercedes-Benz Forum banner

1 - 8 of 8 Posts

·
Registered
1989 300E sedan
Joined
·
2 Posts
Discussion Starter #1
My 300E has developed an overheating problem that is not surprising as there appears to be no water in the coolant system (pipes can be easily squeezed by hand)...however filling it up via the water reservoir does not resolve the problem after running the engine for a short time. Water remains in reservoir and nothing around engine.

It has been suggested that it is a head gasket problem but this does not explain why the newly introduced liquid is not circulating.

Is this a pump problem? And either way have I likely caused major damage by running car off the temperature scale for twenty minutes?
 

·
Registered
Depends on the day!
Joined
·
13,337 Posts
Very well could be..just to the left (drivers side) of the valve cover you will see a number of bolts in the head. They are there to bleed off air, as is the one on top of the t-stat housing. Make sure you have water coming out of those holes before moving on.

Jonathan
 

·
Registered
1989 300E sedan
Joined
·
2 Posts
Discussion Starter #6
apologies bc' the year is 1989, 178,000 miles and the last service was Jan 05 (6,000 miles ago) when the radiator was replaced with pipe work. The radiator was replaced as the connection point for the upper coolant pipe had perished and split allowing steam to escape.

No obvious water leaks or steam from the cooling system this time, although the reservoir overflow did pass thick cream coloured liquid down the inside of the body panel when very hot.

At no point currently does the radiator get hot to touch.
 

·
Registered
1987 300E
Joined
·
2 Posts
Guest said:
Sounds like air lock!!![:(][:(][:(][:(]

Smokie
Hi:

How do you get rid of an airlock problem? Maybe it is related. Thank you.

This is my situation:300E 1987 gas (w124)

So glad you people are around! Thank you ahead of time.

I had a small coolant leak that I could not isolate and every couple of days I would need to add coolant to the reservoir. I added Bars brand liquid (silver) radiator leak fixer to my cooling system, but probably added too much.

The engine now overheats, but ONLY when I turn on the AC. The car will remain at 80 degrees all day long when the AC is off. If I turn off the AC the temp will cool back down to 80 again. The cooling fan is working properly.

I have since flushed the system (four times). I bought a new radiator cap. I noticed after I flushed the system (if the radiator cap was off) and I turned on the AC, the water would heat up and start to overflow the reservoir like it was plugged. It will not do this while the AC is off.

Any Ideas?
 

·
Registered
Joined
·
19 Posts
Sounds alot like a head gasket leaking. The cream colored coolant could be oil & anti-freeze mixing.

I would refill the system being sure to open the vent on the engine.

The vent is the small (10mm, maybe 13mm) hex head copper looking bolt furthest to the front right to the drivers side of the valve cover. Remove the vent before you start filling & replace it when coolant starts coming out, then continue to fill the reservoir.

After that run the engine with the coolant reservoir cap open until the thermostat opens. you may see some air bubbles in the reservoir tank at first but not much. if you see alot of bubbles for an extended period of time, then i'd say it's definitely a head gasket.

Combustion gasses get pushed into the cooling system by the compression of the cylinders. This causes the coolant to get pushed out & you end up vapor locked.

Also you may get coolant in your oil or more steam than normal (sometimes alot more) coming out the tailpipe from the coolant getting sucked into the cylinders on the intake stroke.

you could do a compression check to verify it.
 
1 - 8 of 8 Posts
Top