GM Service Bulletin 14882 - Blocked PCV valve causing Rear Main Seal failure - Page 11 - GMC Terrain Forum
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post #101 of 101 (permalink) Old 04-16-2020, 01:29 PM
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Originally Posted by cmiuc View Post
I have 2013 Terrain.I I took my truck in after receiving notice from GMC regarding oil consumption I knew i had been loosing oil but couldn't understand why. Turns out My rear seal also went out ($2600+ later) . I was told the cause was the hot and cold temperatures. GM repaired the piston ring seal at no cost to me but ......
could the oil consumption malfunction have anything to do with rear seal or exhaust manifold malfunctioning?
You already got a free set of replacement piston and rings?
Are you burning oil again? Ask the dealer to do another oil consumption test, you might get another free set of piston and rings...
Oil consumption is not related to rear main seal failure and visa versa..

Did the dealer scam you with rear main seal replacement? When rear main seal failed, it failed literally loose quarts of oil in a few minutes....

Oil consumption is caused by the process caused LSPI, where carbon falls of intake valves while deriving at low RPM under load, like driving at under 2000 rpm and up a small incline like an overpass on a highway...
The carbon falls into combustion chamber and gets lodged on the pistons upper compression ring, inbetween piston and cylinder wall
Then this piece of carbon becomes oil and gasoline soaked and ignites the combustion charge... instead of only spark plug igniting the combustion charge.
Igniting the combustion charge in the location of the pistons compression ring results in erosion of the steel of the piston in the area of the piston ring grooves, into which the compression rings snap onto and weakens and wears the piston ring itself.
Thus creating a leak path, from crankcase into cylinder for engine oil.

The oil consumption is worsened since high crankcase pressure from piston blowby, pushes oil into cylinders from crankcase, at the same time as piston is sucking air into cylinder during downstroke. High crankcase pressure is not helped by crappy GM PCV design.

LSPI explanation ....==>

Rear main seal failure is unrelated to oil consumption
Rear main seal failure occurs because. You drove your terrain when it was freezing cold outside,. Your rear main seal will fail again if you drive your terrain when it is freezing cold outside.... hence all the discussions on vented oil caps....

My 2 cents ^^^^

2012 Traverse AWD with Elite E2 X catchcan
Three Equinox AWD with 2.4 engine, 2013, 2016 and 2016
2017 equinox AWD with 3.6 engine with Elite E2 X catchcan
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