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Ask Chris (aka-Moose) Your Own Question
Chris (aka-Moose)
Chris (aka-Moose), Technician
Category: Car
Satisfied Customers: 1176
Experience:  16 years of experience
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Negative pressure when oil fill cap is removed, about 500

Customer Question

negative pressure when oil fill cap is removed
JA: When was your last oil change?
Customer: about 500 miles ago
JA: What is the make/model/year of your car?
Customer: 2008 GMC Envoy 5.3L V8
JA: Are you fixing your Envoy yourself? What have you tried so far?
Customer: I took it to my dealer for service, told them that I was using oil about 1 qt every 1000 miles & that I had negative pressure
JA: Anything else you want the mechanic to know before I connect you?
Customer: they replaced a valve cover, suggesting that was the cause. Now I have a check engine light that still doesn't go out even after I added 2 qts of oil.
Submitted: 1 month ago.
Category: Car
Expert:  david craig replied 1 month ago.

Hi Im David, thanks for visiting the site, did they replace the pcv valve and clean out the crankcase ventilation hoses?

Customer: replied 1 month ago.
they did replace the pcv valve, but I'm not sure about the c/c vent hoses.
Expert:  david craig replied 1 month ago.

ok, standby

Expert:  david craig replied 1 month ago.

make sure theres an o ring on the pcv valve