when the cap is off the sound stops and there is a suction at the opening from hole where oil goes.
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2009 Volvo C70 Question: there is a suction through oil cap. when it is on the engine makes a high pitch.
Answer #1bavarican April 16, 2013, 18:51Rookie
The suction is normal.
It sounds like the seal in the oil cap is bad. Usually you can replace the O-ring.
If you can't just order a new oil cap, shouldn't be more than 10 bucks.
Answer #2pushrod April 16, 2013, 19:37Master
Engine breather is stopped up! Pcv system cant pull in fresh air through it.