Oil in the expansion tank (1.8 petrol)

After many cleanings cooling system appeared again oil in the expansion tank, starts well does not smoke and filler cap from the engine is clean.
Could it be head gasket ???

Not much else will do it
Mine was doing it. I stuck some kseal in the coolant and it's gone for another six months so far!

tonytherunner said:

After many cleanings cooling system appeared again oil in the expansion tank, starts well does not smoke and filler cap from the engine is clean.
Could it be head gasket ???

Click to expand...

HG on its way. Get it done before the oil damages the hoses. My MGF did the same thing. It cost more to replace the oil damaged cooling system than fixing the engine.

So that's the beginning damage cylinder head gasket, then becomes increasingly worse ???

tonytherunner said:

So that's the beginning damage cylinder head gasket, then becomes increasingly worse ???

Click to expand...

It shows that the elastopolimer is beginning to separate from the stainless backing.
If you are lucky enough to get this tel tail sign, there's no reason for the repair to be anything other than a simple gasket change job. If left, overheating is likely and the repair begins to get much more costly

I did a pressure test of the cooling system with the engine running at idle and no white smoke, the test was 1.8 bar.
So assume that cylinder head gasket is damaged oil circuit but are a bit confused because the idle oil pressure is 1 bar and cooling system pressure was 1.8 bar so it would have to see the combination of water and oil

Oil is visible in the water because oil separates out. However small quantities of water in the oil steam off. Also dont forget that when the engine is running at speed, the oil pressure is around 3 bar. This will force oil into the water. Water may not get into the oil in sufficient quantities to cause emulsification. The oil in the coolant is key. It's a definite sign that the HG is de-laminating.

I've seen this many times. Even my own VVC MGF engine did the exact same thing. It filled the cooling system with 3 litres of oil, however no water got into the sump.

It's true. It doesn't always go both directions or not to a noticeable degree at least.

thanks for answers
Gonna give it a try in the cylinder head pressure test should be seeing some bubbles in the cooling system or high pressure in the sump ....


the cylinder head gasket should be used ?? I like elring company would be good a head gasket for k series???
(MLS is good??)

the inlet manifold gasket is always worth investigating before hgf, especially if there is only trace of oil.

freelance said:

the inlet manifold gasket is always worth investigating before hgf, especially if there is only trace of oil.

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Intake gasket was checked, no sign of failure

Appeared more oil in the expansion tank so I need a new head gasket

which is the best head gasket ???

tonytherunner said:

thanks for answers
Gonna give it a try in the cylinder head pressure test should be seeing some bubbles in the cooling system or high pressure in the sump ....


the cylinder head gasket should be used ?? I like elring company would be good a head gasket for k series???
(MLS is good??)

Click to expand...

The pressure test will only show you if the fire rings have failed. The HG starts to delaminate before the fire rings let go. The fire rings generally only fail because the fluids leak out or become mixed.

tonytherunner said:

Appeared more oil in the expansion tank so I need a new head gasket

which is the best head gasket ???

Click to expand...

I like the fit the latest Payen elastopolymer gasket. It's more forgiving to the gasket faces.
MLS gaskets can leak coolant from the head/ block joint.

Thanks @Nodge68

someone recommended me something like this
The Kavachi (Ultimate) Head Gasket - MG-Rover.org Forums

tonytherunner said:

Thanks @Nodge68

someone recommended me something like this
The Kavachi (Ultimate) Head Gasket - MG-Rover.org Forums

Click to expand...

The SIAC gasket linked can still leak at the block face. Been there done that.

The Payen Elastopolymer will last longer than the original gasket and is much easier to fit as you don't need to replace the oil rail to use it.

freelance said:

the inlet manifold gasket is always worth investigating before hgf, especially if there is only trace of oil.

Click to expand...

Why? There's no oil channel in the inlet manifold, is it?

tonytherunner said:

Thanks @Nodge68

someone recommended me something like this
The Kavachi (Ultimate) Head Gasket - MG-Rover.org Forums

Click to expand...

That was a first rate article to read!