Quote:
Originally Posted by jerisc
I asked pretty much same question as OP. I got an in-depth about what blow by is.... (I know what blow by is, my husband's been a mechanic for ever). What I didn't get was why blow by is an issue on these engines (LLT & LFX). I understand the concept, I don't understand the need or issue - UNLESS this causes more problems later down the road than anything else I've driven over the last 30 years.
|
The blow by in and of itself may not be particularly worse on these engines. However, the blow by (and other crankcase vapors--it's more than just blow by) that the PCV system sucks into the intake manifold is a problem on these engines in particular because they're direct-injected. There is no detergent fuel washing the intake valves and keeping them clean, so they build up carbon deposits.
Not only that, but just burning the crankcase vapors will affect performance to a degree, causing knock retard.
Plenty of reasons to keep that crap out of the intake, IMO.