greasy deposit in engine oil filler

[iaintaylor]

Just done first oil change since my daughter bought a 4 year old, 36000 miles, Renault Clio. When I removed the engine filler cap there was a thick, white, greasy build up inside the cap and filler tube and deposits inside the OHC space. Any ideas what might have caused this. I suspect mixing of incompatible oils by previous owner but not certain.

 

[HDi fun]

If it's white it's more likely to be water and oil mixing. It might be simply that the engine has only done short journeys and the water present is simply a result of condensation. Simple fix for this is a good hard drive for 1/2 hour or so. Do read on before proceeding.

It is possible that the cause is a failed head gasket, in which case it's best not to work the engine too hard and get it inspected (pressure tested) first to determine if this is the case.

 

[obi_waynne]

Keep an eye on it. A white mayonnaise is a symptom of gasket problems. Make sure it doens't over heat.

Hopefully as HDI says it was just the condensation that had built up. A lot of low mileage cars have only ever done short journeys and condensation build up occurs.

 

[HDi fun]

My father's car has exactly this problem and it is a result of short journeys. We've had it pressure tested and the gasket is sound.

It's not so much cold starts which are a problem, it's the cold stops which leave the engine full of damp air. This damp air can be pretty corrosive as well - not good for engine internals.

 

[Richard1]

The most common cause is the short trips, especially in cold damp weather. One of the reasons I take my wife's car occasionally when I'm going outside the city (both my Grand Cherokee and her Outlander are 2 years old. My GC has 38,000 km, her Outlander 9,000).
This is a major reason for the new ILSAC GF-5 spec (with the API SN). The sodium Sulfonate detergent helps keep that from clogging up the engines.

Of course it could be from a leaking head gasket. Keep an eye on the water level. If it drops. You need a leak-down test to confirm the gasket.

 

[jarrus]

Sniff test is the easiest way to tell,

You "sniff" the water in the coolant, using a certain chemical to see if there is any hydrocarbons (oil) in the water, if the chemical in the vessel changes colour then it's a new head gasket is needed. Buy a genuine part for something like this as a patent part is likely to give you problems in the future.