No Compression in Cylinder 3 and 6

[Uncle Gump]

Well... at this point there isn't much left to discuss.... time to start tearing it down and see what happened.

 

[Slow3.4oh]

Well... at this point there isn't much left to discuss.... time to start tearing it down and see what happened.

Yeah, hopefully its just a burnt or cracked valve. I have the gasket set for it, just need to tear it apart i guess.

 

[MikeG]

So it's now a 2.0.....

 

[RonD]

3.0l runs 9.3:1 compression ratio(CR)

General rule if thumb to estimated expected compression in PSI is.... 18 X CR = PSI

So expected compression is 167psi, and that's a cold engine, and under 2,000ft elevation above sea level, you can expect a LITTLE less in say Denver at 5,000ft elevation
The "18" comes from 15psi air pressure + 3 for the mechanical compression of the air, just FYI

120psi is not "normal" for any vehicle engine, but we can chalk that up to the gauge, since 4 of the cylinders were 120
So if gauge is off by say 40psi then 3 and 6 are at 50-70psi, which would usually be a valve issue

If you think the compression gauge is accurate then you may have a timing chain issue ON TOP OF a valve issue
And 3.0ls never had timing chain issues, literally unheard of on those engine, they don't even have a timing chain tensioner..........one of the few engine's with cams that doesn't

 

[Slow3.4oh]

3.0l runs 9.3:1 compression ratio(CR)

General rule if thumb to estimated expected compression in PSI is.... 18 X CR = PSI

So expected compression is 167psi, and that's a cold engine, and under 2,000ft elevation above sea level, you can expect a LITTLE less in say Denver at 5,000ft elevation
The "18" comes from 15psi air pressure + 3 for the mechanical compression of the air, just FYI

120psi is not "normal" for any vehicle engine, but we can chalk that up to the gauge, since 4 of the cylinders were 120
So if gauge is off by say 40psi then 3 and 6 are at 50-70psi, which would usually be a valve issue

If you think the compression gauge is accurate then you may have a timing chain issue ON TOP OF a valve issue
And 3.0ls never had timing chain issues, literally unheard of on those engine, they don't even have a timing chain tensioner..........one of the few engine's with cams that doesn't

Well that would be completely possible if my compression tester is off because I found it in my house randomly like 6 years ago, so that sounds like a possibility

 

[Slow3.4oh]

So it's now a 2.0.....

Yes