s40,2006,whining noise in engine compartment

[the5tds]

our volvo s40 started a whining noise yesterday afternoon,after driving about 20 min.It again did it when my husband drove it to work this am,seems to only do it after engine gets warmed up.if its cold it doesnt do it.He removed the oilcap this afternoon when he got home and the noise stopped.is it possibly an o ring on the cap needing to be replaced, or is it more likely something else? Thanks

[billofdurham]

Welcome to Matthew's Volvo Site.

This is another new one for me. There is an O ring/gasket on the filler cap and it is possible that it is no longer working as it should. There is a pressure build up in the engine which could force its way past any small defect in the O ring. Usually oil is forced out in a fine vapour but this may be accompanied by a whining noise.

The O ring will be relatively cheap and, as the noise stopped when the cap was released, I would be changing it.

Check the links to our sponsors at the top of the page for the price.

Bill.

[OEMVolvoParts]

This sounds like it may be the oil filter housing, which has a diaphram that will break. Volvo will cover it under an extended warrany if that is the case. Most people describe it as a whirling or fluttering sound.