Looking for some help with my compression test results

engine codes P0302 and P0304

I checked compression dry and wet results below:

DRY
3-130. 6-121
2-90. 5-121
1-150. 4-121

WET
3-160. 6- 150
2-120. 5- 150
1-180. 4- 150

I replaced both heads about a year and a half ago due to recessed valve seats TSB. Ran great up until now. Flashing CEL under load.


does the higher number on wet test indicate worn piston rings?

Or could it be heads even though only 18 months old?

truck has 230,000 miles

any feedback much appreciated, thanks

 

By the look of those numbers and mileage, I'd say it's time for hone and rings or re-sleave and rings. Valve lapping while your in there.

 

Thanks, does the wet test definitively prove that it’s the rings? Is there a chance it could still be heads or cracked block? If it is the rings, do you think it is worth doing. Thanks for your input

 

I don't believe that your block is cracked. It's just at the point of a rebuild. Is it worth it? That's solely up to you. One day when my 03 gets to this point, I'll drop a crate motor in it and love it for many more years. But yes, on my opinion, wet test definitely shows it's got lots of blow-by.

 

Do you think a leak down test is necessary? Or does the compression and wet test prove the issue. I’m surprised about the low compression because the replaced heads are only 18 months old. Iv never done valve lapping before, but assumed that would have been taken care of on the new machined heads. If it is the piston rings, do I replace the rings only or pistons too? Thank you for your answers and time.

 

Rings only may do it with a good hone, but your already in it so far, why not just do a full lower end rebuild? Ill guarantee you have piston wear at this point too. It would suck to do your rings only and weeks to months later have a piston crack. Your heads are fine. I only mentioned the valve lapping to clean your valve seats as I'm sure with your numbers, your getting some oil deposit up in there.

 

A leak down test will just prove that you've got blow-by. Your heads are fine I'm sure. I'll put my money on it solely being your cylinder liners and rigs. Get a lower end rebuild, throw those heads on and enjoy your truck.

 

Cool, thanks man. Gonna start the tear down today. Good news is that it’s not my daily driver so I can go at my own pace. I’ll keep you updated on the process. Thanks again.