Headgasket failure on M111 engine...

[Vronsky]

Car idles badly for ca. 20 sec. right after starting (both cold & warm), and lately the coolant level indicator light goes on and off at times. MB dealer now says the headgasket leaks coolant into one of the cilinders. 1996 M111 engine has done 140K miles.

I'm looking at a repair of 1100 Euro.

Is it likely their diagnosis could be wrong?? My understanding is that headgasket probs on M111's are very very rare.


Thanks!

[Rob Pruijt]

If the head gasket is leaking it is possible that water get into a cylinder.

The most common symptoms are:
1- very hard first crank after the engine was not running for a while (overnight).
2- Large amounts of white smoke from exhaust
3- Water in the oil (oil level rising)

If your car is just idling bad for 20 sec I would recommend further diagnosis before you have the engine taken apart.

You state that the coolant indicator comes on sometimes, do you add coolant or just wait for it to go off again?

[Gus67]

Do a compression test.That will tell you for sure if you got a leak.Also check the sparkplugs.They are the best insight to how a car is operating.If 1 of them is fouled then you know something is up with that cylinder.Good luck.

[Vronsky]

No white smoke, easy starting at all times. Just the bad idle.
Fluid in expansion tank was clear. Didn't check oil.
Dealer says they did a compression test, and had to add 1,5 litre coolant (never added fresh fluid myself).
They are certain it's the headgasket.
Still don't understand why the coolant light went on and off (should stay permanently on, I'd say).

Indy garage offered a cheaper price, but I'm thinking that for these type of complicated jobs, the MB dealer is still the right place (& 2-year warranty on repair). They're also renewing the valve stem seals while the head's off.

The M102 engine in my previous W124 also had a headgasket failure, aswell as a worn diff btw, that on my W210 is now also becoming audible

[t walgamuth]

the low coolant light is probably a simple float like in a toilet tank. when your coolant is cold it occupies less space as it shrinks. hence may indicate a low level. when it warms up it expands so no indication. it may also be located in a place where cornering or braking might affect coolant level at the indicator float.

good luck. hope it is not the head gasket but it sounds like a good chance it is. i am not sure a compression test would always be a good indicator. of this.

also you may experience bubbles and excess pressure in the cooling system.

tom w