W124 E280 Coolant Loss

[DAVIDMcDOWELL]

She loses about 1 litre for every 400 miles driven - is this unusual? If there's a fault, what is it likely to be? Mileage is about 250K, driving style is average.

 

[grober]

Cylinder head gasket on the way out? Any other signs of leaks elsewhere? thermostat housing seal, damaged water pump, leaking hose clips, any water in cabin from leaking heater?

 

[Dave Lewis]

It is indeed unusual. Time to investigate for leaks, perhaps water pump is failing? These seem to need replacing every now and then.

 

[Ian B Walker]

Check the gear box too. Make sure that the rad and (integral) oil cooler are intact.

 

[bolide]

With that kind of mileage it could be any of the above or a pinhole in the radiator. This normally shows itself with a small pool of water under the car after it's been parked a while

Pressure-testing the cooling system would be a good start to see if the CHG is suspect

Nick Froome
www.w124.co.uk

 

[imadoofus]

First time I had this on my 320 it was a pipe into the NSR of the block which was loose.

Second time, it was the water pump. Remove the engine undertray, and see where the damp patch is. This will give you an indication of where the fluid is leaking from.

PJ

 

[Vlad]

First time I had this on my 320 it was a pipe into the NSR of the block which was loose.

I've also had this problem on a 280....there is also a little "O" Ring that fits into the block where the hose goes into the block and this can perish.

Get a powerful torch and shine it at the back of the block and see if you can see any wetness....preferably before it dries off.

 

[Mercedes cozy]

check your coolant header tank, any sign of oil as this is a common problem with the head gasket to go

 

[bolide]

We need a water leak / potential CHG failure checklist as a sticky. Something like:

1 - check for mayonnaise in the oil filler cap
2 - check for mayonnaise in the header tank
3 - check for water in the engine oil via dipstick
4 - check for water in the gearbox oil via dipstick

etc, etc


Nick Froome
www.w124.co.uk