Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Contaminant in oil

My 2004 +4 has covered 48,500 mls.
I was topping up the oil at the weekend and as I removed the filler cap I noticed a white deposit on the underside of the cap.
My experience with much older vehicles is that the white residue could be evidence of water contamination. Damaged or failing Head gaskets we're often the culprits in those days, allowing water to migrate into the oil ways.
Does anyone have similar experience?
The white emulsion is minimal, is that usual or acceptable ?
Could there be an alternative route by which the water could gain access to the oil way?
All the best
Tony

Hi Tony, hope its not that serious! What does the oil on the dipstick look like? Do you have to top up oil regularly? Does the level of coolant go up or down? If you do short runs it could be condensation?
Cheers J

As you rightly say its water oil mix, but if its only a minute amount around the inner edge of the cap and you have no signs of water loss, it could be a slight condensation issue, not been familier with what engine you carry, it would be wise to check for colapsed,blocked or porous breather pipes.

I could regularily witness the same on a Peugeot 106 I owned.
White goo arond the oil filler cap.
But only in winter when being driven often for very short distances(in Norway). Longer runs would remove the white goo.

JJW and deanroyal has sensible advices.

A blown head gasket can sometims be seen if it's bubbling in the expansion tank

Tony....what sort of use is the car getting? Short journeys in cold weather is going to cause condensation in the engine and the typical "mayonnaise" under the filler cap.

Chaps, thanks for your observations, the engine is a Duratec 2.0l.
I use the car every day, short distances in all weather.
Oil is clean and use is minimal, power is good and mpg is 40 (regular monitoring), coolant is ok, no loss anyway and no evidence of bubble.
Dip stick is clean.
The residue is minimal, I have cleaned the cap and will monitor, it might very well be condensation given the conditions that I have been driving in recently - I had not thought of that.
All the best for now,
Tony

From what you describe, classic symptoms of mayonnaise due to the engine not getting hot for long enough to drive off the water collected by condensation. Yours seems a minor case though.

Some cars just seem to be more susceptible, while others, despite the conditions seeming being more ideal, don't do it.

More longer runs, and more engine compartment heat are the crude answer.

Thanks Martyn, I think you are correct. We will go on a long run and see if it remains.
Thanks again,
Tony

Mayo was very common in the 80's on BL cars with FWD - Maestros and Montegos suffered from it quite badly. A long run should shift it - get the oil hot.

Cor - I'm a competent garage...

Must be, I've got a pressure tester (and caps/adaptors for most radiator types).