Hi all

I bought a 1996 Mercedes C280 only yesterday from Accrington. On the drive home to Bristol, I had to stop 7 times to top up the coolant level after the warning light lit up. At no point was there any over-heating or noticeable loss of performance.

I have checked the engine bay and underneath the car, however there is no evidence of leakage.

It may also be worth mentioning that the car can sometimes idle as low as 400 revs, and when starting can fluctuate slightly. It is also judders when stationary. Additionally, there is an issue with the accelerator pedal which requires significant depressing b4 it jolts forwards. When reversing, it is so bad it is dangerous. I doubt these problems are related to the coolant, but any advise would be most welcome.

Thanks in advance.

 

Hi,

Confused whether it is using water but not leaking externally or the light says it needs water but when you check there is nothing wrong.

Sure the warning light is Low Coolant and not the Screenwash level.

If indeed it is the coolant level light AND if you are adding water it must be going somewhere. This sounds like either a cylinder head gasket problem (most likely) or possible a ruptured oil cooler (water/oil). Have you checked the oil level/condition. Is the level high? Is the oil like mayonaise? How much water did you add?

Idle should be about 700. You dont state whether it is man or auto. 400 is definitely too low and will cause the shudder at idle. There isn't any form of manual idle screw to adjust. It is all computer controlled. Possible result of a bad head gasket (one cylinder out). C280. Is the 4 or 6 cyl. I'm not familiar with the specific model.

Jolt into forward/reverse (I guess its an auto) may well be due to the idle/strange throttle pedal which in turn may be due to the coolant problem) but may be all sorts of things. The throttle pedal is drive by wire with no physical cable or linkage between the pedal and the engine.

Who sold you the car? Private or a dealer? You may need to get independent verification of the cars condition to support any claim.

Does the CEL (Check Engine Light) come at Ignition On. It should!!
Is it on once the engine is running. If so need to get the codes read. If not then something very strange is going on. Somebody has possibly disconnected it to hide a problem.

Is the bad idle only when hot or also cold etc.

Need more history from previous owner etc.
Keep us posted. Stuart