Head gasket changed and now getting water in the oil.

[Mercedes 230te]

Hello all.

I have a 1988 w124 230te which I have just changed the head gasket on.
It was blowing water out the exhaust before. Now gasket is changed.
I ran it for a minute or two and noticed the white foam type stuff on the inside of the oil cap which was not there before. I turned it off as it worried me.
Could this be residual water from before getting into the sump of do I have a more serious problem.

It also sounds like it's miss-firing but I know I have the firing order correct.

Head was alloy welded and skimmed when off, and block was cleaned a best as I could.

Any help would be very much appreciated.

 

[DSM10000]

Sorry to hear of you problems, as the head pressure tested after being welded and skimmed?

 

[Mercedes 230te]

Hi there thanks for getting back to me.

I don't think it was as it was not on the receipt from the engineers. unless it's part of the service when skimming.

 

[grober]

Did you change the oil and filter when you renewed the gasket? Did you do this gasket change yourself? Did you use a MB or Reinz gasket and new cylinder head bolts with the correct tightening sequence?

 

[jaymanek]

foam after a minute or two of running is far too quick for any actual mixing to occur and circulate into the system... I think you need to run it for longer and see what happens before panicking.

I think its just condensation on the oil cap which always occurs when you run a cold engine for a short time.

 

[Mercedes 230te]

Hi Grober. Thanks for the reply

No I didn't change the oil and filter when I renewed the gasket. But there didn't seem to be any on the cap or dipstick before I changed it. Yes I changed the gasket myself. I used a gasket from my local gsf motor factors and used new bolts with the correct tightening sequence.

 

[Mercedes 230te]

Hi Jaymanek. Thanks for the reply.

I don't think it's just condensation on the oil cap because I just drained the oil and about 4 litres of it is creamy but then clean oil started co come out. and the dipstick still has clean oil on it.
Unless I didn't run it long enough for all of the oil to mix. I don't seem to have lost any water either.

 

[markjay]

When skimming the head they will usually also pressure-test it.

I would change the oil anyway because it is likely to have some coolant content from before. Additionally, regardless of how clean an environment you worked in, some dust will have entered the cylinders and oilways while the head was off, so an oil and filter change will be good.

And as said, 'mayo' under the filler cap is usualy not a cause for concern, mayo on the dipstick is.

After changing oil and filter, try again and see what happens.

 

[Mercedes 230te]

Markjay thank you for your reply.

When you say, 'mayo' under the filler cap is usually not a cause for concern, what about the 4 litres of mayo I took from the sump. (The dipstick still has clean oil on it). Would that be normal considering I didn't change the oil and filter after changing the gasket. Also I didn't drain the engine of coolant when I did the job. Could that have anything to do with it?

 

[markjay]

You must change the coolant, it will have oil in it.

The amount of mayo in the oil will depend on how bad the situation was beforehand.

Keep in mind that when the engine is hot the pressure in the cooling system will be higher than that of the oil, and coolant will enter the oil.

But when the engine is cold, the oil pressure will be higher than the cooling system pressure and you will get oil entering the cooling system.

Given that you only ran the engine for a few minutes it is unlikely that much coolant if any has entered the oil during this time as the coolant would have been cold and not yet pressurised.

I would change oil and coolant and try again.

 

[Mercedes 230te]

Thank you very much for your advice.

I will do this.

Do you think it's just a case of old oil and water from when the gasket went previously.
Also is possible the head gasket could of blown again as soon as it fired?

 

[Dieselman]

Unlikely, unless the bolts were loose.

Change the oil and water immediately. Glycol in the oil will wreck the crank bearing material.

 

[Mercedes 230te]

Thank you Dieselman.

Do you think it's just a case of old oil and water from when the gasket went previously?

 

[Dieselman]

Yes.

I am more than a little surprised you didn't change the fluids as part of the job. You should drain the coolant before removing the head to stop glycol transfer...but a lot of mechanics don't bother.

Don't forget to use the block drain, otherwise you will be changing only about half the coolant.

 

[Mercedes 230te]

I did drain the coolant from the rad but at the time I didn't realise I had to drain it from the block too.
Thank you for your posts.

 

[Mercedes 230te]

Does anyone think this could have anything to do with the miss-fire it's having too.

 

[grober]

First time you mentioned that one! If you remove the plugs and have a look down the plug holes with a small torch if the top of any of the pistons look "oily" and the plug black and oily then that's a sign water is still getting into the cylinder.
ps ask any MB mechnic and he will tell you to use Reinz or MB gaskets-- What make did GSF supply? they usually use Reinz?

 

[Mercedes 230te]

Hi grober. I did actually mention this in my first post. They supplied one called elring.

 

[grober]

Elring have a decent enough reputation.

 

[markjay]

I am assuming this is the M102 engine, which is SOHC, in which case the misfire could also be result of cam timing or other camshaft-related issue. A compression test will help diagnose the issue.