M111 engine oil leak ?

[shanksy]

Hi all, I recently had a problem whereby oil was leaking into the coolant.
No water was getting into the oil fortunately.

It got to the stage where the engine was overheating and the coolant was nothing but sludge so I completely drained the system, spent ages cleaning the rad and all hoses etc, replaced the suspected head gasket and thought the problem would be sorted.

After running fine for a couple of weeks sludge has started to appear in the header tank again and the engine occasionally runs a little hot before returning to a normal running temp.

Now I am thinking that there was maybe some sludge left in the heater matrix or somewhere which is why it has returned, obviously I am hoping this is the explanation and a couple more flushes over time will sort it.

What I wanted to ask was if there is any other possible source of the sludge as I don't want to keep forking out for antifreeze every time I flush if it is in fact new sludge and not just the remnants of prior to the gasket change.

As always, any advice greatly appreciated......
Cheers

 

[Scott_F]

Did you have the cylinder head skimmed to remove any distortion when you replaced the head gasket ?

 

[shanksy]

No, once the head was removed it was deemed not necessary at the time.

 

[BlackC55]

Did you crack test the head?

Were genuine gaskets used?

Is the head torqued down properly?

 

[grober]

One cause of CHG failure on these 111 engines was cylinder head bolt stretch later rectified with better bolts. For that reason I would always renew the cylinder head bolts when renewing the CHG. As Ollie says the heads can develop cracks or become porous/ corroded if the casting is particularly weak at certain points - they need to be repaired professionally by a engine rebuild specialist if this is the case.

 

[rawc43]

it could be the oil cooler

 

[shanksy]

Ok, the head wasn't crack tested but the new gasket was the MB part and the head was definitely torqued down properly.
You could see from the the old gasket that it was definitely leaking so at least I havent done a needless gasket job.
The head bolts were not replaced as the originals were well within the stretch limits.

Is the oil cooler really a possibility ?

 

[grober]

Are you sure its engine oil and not transmission fluid from the gearbox escaping via the heat exchange coil in the radiator which has corroded thro? Unlike the well known Valeo radiator problem where failure occurred pretty quickly due to a manufacturing defect this would be down to the ravages of time and lack of proper coolant renewal of a previous owner. You could get a check for glycol in the transmission fluid done by a autotransmission specialist but it might just be worth changing the radiator as a precaution?

 

[sagesingh]

I had this problem recently, had the gasket redone. there was still some sludge coming through for about 2-3 weeks after. it just takes time and it will clear eventually. There is some powder that MB use to clean the system out, might be worth while using that to help the sludge though.

the oil cooler is a possibility though, i have a spare rad i just took off my car, its not an original MB one but is still good. PM me if you are interested. Its been used for about 3000 miles.

 

[shanksy]

ok think i'll just try another flush for the time being and see how things settle.
Thanks for all the advice

 

[RobinA3]

Sorry to drag up an old thread but what was the outcome of this?

 

[godriver]

Sorry to drag up an old thread but what was the outcome of this?

seriously guys ? outcome

 

[shanksy]

It turned out to be just remnants of what had previously clogged up cooling
It took quite a few flushes with coolant flush (forget which make) and quite a bit of time and eventually ran clear.

If you have had sludge build up over time and to the extent I had, you will likely get the same after fixing the problem. Frustrating I know, always having that doubt in the back of your head its still leaking in.....