Contaminated Oil

[v8 dreams]

Just noticed today whilst checking over my E240 that there is 'mayonnaise' on the inside of the oil filler cap. Exactly what this means I'm not too sure but I know it's never good news. Water in the oil somehow? Head gasket failure ? Definately was not there when I bought it (from Merc main dealer) 9 months ago.

It's a 51 plate car with full MBSH and 33k on the clock. Should I try to get Merc to fix it or get rid of it fast ?

 

[peterchurch]

Is the car under a waranty? If so claim! and do it asap
if oil and water are mixing then it sounds like the head gasket has blown...
Eitherway water should not be in the oil

 

[v8 dreams]

It's just turned 3 years so out of Merc warranty but when you buy a car that's 2 and a bit years old from a dealer as I did they make it up to 12 months with an off the shelf warranty. I was assured at the time this is just as comprehensive as the Merc one so I'm hopeful.

 

[LNM]

_When_ you claim on the warranty, make sure you see a reciept from the dealer that indicates that the head(s) have been skimmed. My receipts from previous owner tell me that it had a head gasket done at a dealers and they didn't get it skimmed. Spectacularly incompetent, some would say negligent and very risky behaviour, considering the previous owner was (and still is.....) a highly litigous solicitor.

I believe that you risk a doomed engine if you drive too much with it in your indicated state.

 

[cheesyget]

First of all let me say that I'm an old car person so moderns aren't my field of expertise, but gloop in the filler cap isn't always a sign of doom. Cars that do lots of short trips tend to get it because the engine never gets hot enough to get rid of condensation under the rocker cover and it mixes with the oil around the filler cap. On my VW for example the filler neck is a long way from any hot engine oil so that's always got a quantity of cottage cheese on the underside of the cap.
What's the oil in the sump like? Creamy = water present. Similarly, is there any evidence of oil emulsion in the radiator header tank?

 

[jberks]

Hi,
I found mayo on the underside of the oil filler cap. However, the water is clean, the oil on the dipstick is clean, the neck is clean, it doesn't use any water whatsoever (Never put a drop in in 4 years) and aside from 1L oil every 4k or so, no oil either.
At the last service the dealer changed the coolant as well as the oil and handed the car back as ok so I cleaned the cap and put the mayo down 5 years worth of condensation.

Try cleaning the mayo off and monitoring it for a while.

 

[sooper coop]

I'm in the company of knowledge however it isnt gloom at all, my corrado vr6 5 years ago had gloop and the sure fire test is if thee are bubbles in the dip stick.

quite often is conden-gue.

keep an eye on fluids etc, there is a cheap test hat can be carried out as well at any garage.

 

[mlc]

I'm really pleased to read that I am not the only one that's old enough to think that this isn't automatically the end of the engine! I was taught at an early age that for every gallon of petrol burnt a gallon of water gets into the oil, if we go back far enough this was just vented into the air, but for the last 30 years at least the main solution was to vent the upper cylinder air (and moisture) through the air intake, so any fumes getting past the pistons, or anything coming off the oil is sucked back into the induction system. This works fine as long a: the engine gets hot and b: nothing gets blocked. Anyone that ever saw a Ford CVH engine on a bad day in the 80's will understand what goes wrong when the breather pipes get blocked.

I agree that if the oil on the dipstick is looking good, your are not losing water and the car is running ok the first step is to clean up and monitor for a little while, if it comes back then you need to take further advise.

Mark.

 

[robbo]

Hold your horses guys!

This is completely normal with M112 engines in cold weather. The oil filler cap is mounted in a housing that is slightly cooler than the rest of the engine and as a consequence in cold weather (like we have been having), moisture from cold starts condenses and forms a slight emulsion/mayonnaise. It'll go away when it warms up a bit.

Nothing to worry about.