I removed the plug & wire cover over the weekend and there was a bit of oil pooled on top of the engine. Not very much -- but I can't figure out where it came from! There's nothing wrong with the plugs, and the oil is in one of the little recessed areas of the engine itself, not on the plug wires. Is it possible some oil could have leaked out of the filler cap somehow? Is that common, and does it indicate I need a new gasket on the filler cap?
Thanks, I'm mystified!

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87 745T, 97 855. Nine out of ten Black Labs recommend Volvo wagons!

Thanks all -- checked the filler cap gasket and it doesn't seem as pliable as I think it should be, so I'll replace that and see what happens.
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87 745T, 97 855. Nine out of ten Black Labs recommend Volvo wagons!

Probably as simple as you cap gasket. But your oil trap (aka oil separator box) behind the intake manifold may need replacement or cleaning. Seems that one symptom of this condition is oil pushing out of the blowby outlet on top of the engine and the oil cap. Do you also get crank case smell in your cabin when you run the heater using external air. That's another symptom. Anyway, do some searches and see what others have said about this. Good luck. John

How does one clean the oil separator? I have had this problem and want to clean the oil trap but I don't know how.

I'm planning on doing mine and from readings it is just a container.
The hose from the pvc (near the oil cap) recirulates the internal gases and goes to the oil trap. Any oil that may come down will drain back into the oil pan the the gases go back into turbo air intake.
I would suspect that the container opens up and you simply clean it out and making sure you dont move the hose going to the oilpan. I've also read at the time of an oil change you can pour down engine cleaner (gunk) down the pvc house. Oil plug out (no oil in engine) and let it do its job.
But I think I'll do the manual clean of removing the intake manifold.

Yup, no doubt you need a new filler cap gasket...had the same problem, new gasket, gone.

Anyone adding oil will spill a little bit, and that is where it collects. Just clean it up.

Klaus
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98 V70Rawd(101Kmi), 95 854T(85K mi), 75 164E(173K mi)

More than likley all it needs is the oil filler cap gasket.

Try tighening up the oil separator hose that connects to the oil filler. It may be a little loose.