Loud hissing noise when I remove Oil Filler Cap

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11-24-2017 | 04:37 AM

EsRay

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From: Dubai

Loud hissing noise when I remove Oil Filler Cap

Hello Forum,
A loud 'hissing' when I remove my oil filler cap with the engine running - Could this be a blocked Crankcase Breather or a vacuum pipe and if so, where are the likely culprits on a 2005 XJ8L, please?
Regards,
Ray

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11-24-2017 | 06:16 AM

Box

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From: Up, Planet Earth

You shouldn't run the vehicle without the oil cap installed. Unmetered air will cause you all kinds of issues. The crankcase is a sealed system, and is why the inlet is in the breather hose after the MAF. Both the o-ring on the filler cap and it's tower as well as the dipstick should provide positive sealing.

Last edited by Box; 11-24-2017 at 06:20 AM.

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