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Old 11-18-2025, 08:50 PM   #1
OldCreek
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Join Date: Jan 2007
Location: Central Coast California
Posts: 1,035
2005 6.0 Lq9 PCV blockage

I put an LQ9 from a 2005 Cadillac Escalade in my K5 roughly 15 years ago. I've only put around 5,500 miles on it since then. I have not done yearly oil changes...

I'm not much of a diagnostician but it sounds like the PCV and increased crankcase pressures that are causing my problems...

Recently, it is idling rough and driving even worse. No codes are coming up. It smells rich but it always has and I'm not running cats. There was some noise as if there was an exhaust leak and I've noticed more leaking of engine oil (haven't looked close enough to see where.) I haven't noticed any significant oil consumption but then again I'm not driving it that much.

During my trouble shooting, I pulled the MAP sensor and noticed oil on it. After replacing with a new one the motor ran well for a few minutes but symptoms appear to be returning. My online research leads me to PCV failure/blockage. And further research shows that my engine doesn't have a PCV valve, per se, but has a fixed orifice valve/nipple.

So, is it likely that the valve cover baffle drainage holes are blocked and the PCV nipple is blocked, too? Is it simple enough to clean out the drainage hole and maybe even drill it out to roughly 1/4"? And maybe add some drainage holes to the baffle? Or, should I just get the new updated valve cover? And, maybe drill that out a little to ensure proper drainage? No, I won't drill the orifice itself, if that's even possible.

Would you install an inline oil catch can, too?

Yes, better oil change schedule may be helpful, too.

I'll likely pull the valve cover this weekend...

Thanks,

Wil
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1972 K20 Suburban 5.7/700r4/NP205 Dana 44/H052 Sold
1972 C10 5.3L/4L60E 12bolt 5Lug - Sold
1971 K5 Blazer 6.0L LQ9 4L60E NP205 Dana 44/H052!!!
1970 K3500 1ton CrewCab 8.1L/Allison1000/NP205 Dana 60/14B!!!! - Sold
1988 V30 CCLB 7.4L/TH400/NP205/Dana 60/Dana 70!!! (Sold)
2003 K2500HD 8.1/Allison1000/NP263

Last edited by OldCreek; 11-18-2025 at 09:00 PM.
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