LB7: lots of smoke and burning oil

[OregonDMAX]

I guess you could say its a possibility but unlikely in my case. I have no reduced power and the smoke coming out of the oil cap says the issue is more internal.

An issue with the turbo would be more black smoke out the exhaust and low boost I would think. My smoke is blue

 

[Andrew]

how many miles are on your truck?

 

[OregonDMAX]

Mine? Just hit 145k.

 

[OregonDMAX]

I always unplug the ficm when doing a compression test as well. Works great

Do I need to disable the GPCM also or will having the glowplugs out and disconnected be enough?

 

[Andrew]

Mine? Just hit 145k.

yes sorry man im just tossing this around would it be possible that a valve seal let go? or is wore enough to let the oil enter the cylinder (explain the blue smoke but good comp)

 

[OregonDMAX]

I just did a compression check. All 8 cylinders were roughly the same, with most being 320-330, cylinder 6,8 were 310 and cylinder 4 was 335.

All the glow plugs came out super easy but one of them has a white tip. Not sure what that means but it looked a little corroded that cylinder was 310.

 

[Andrew]

pretty sure white ash is a sign of burning oil. i dont think a compression test would be able to tell if a valve seal was bad dont hold me to that tho

 

[OregonDMAX]

I'm not sure but it was the only one that didn't look good.

I tested all 8 glowplugs also, turns out two are bad. Which would account for my difficult starting the past several weeks.

 

[02greysixer]

You disabled the fuel by unplugging the ficm right? Your hard starting may be from the slightly low compression. It's pretty safe to say you're 50psi or so low all the way around for a stock motor. I'd definitely do a leak down but if I was going to have to take a guess it sounds like rings to me

Sent from my SAMSUNG-SGH-I337 using Tapatalk

 

[OregonDMAX]

I pulled the ignition relay and the connector at the GPCM for the test.

The hard starting is only at single digit or below so I credit the two GP's to that. The bag GP's were on cyl 1,3

As far as the compression its not great but at least they are all somewhat even. What gets me is the majority of smoke is from the 2,4,6,8 bank and 6,8 were 310. And 2,4 were 335.

 

[OregonDMAX]

bump, still lost and

 

[Chevy1925]

you need to do a leak down test as stated before.

your compression is pretty darn low across the board. my bent rods showed the same numbers as your showing but with cyl 5 at 250psi, rest were 300-330

 

[OregonDMAX]

ok that i can do.
is a legit leakdown tester needed or can i make one with part of the compression tester and a regulator and a gauge. really getting tired of spending money to possibly find out i have to spend a shit ton more on a motor.

 

[Chevy1925]

That should be fine. you just gunna need to make sure each cyl you test is at TDC on the compression stroke. if your finding your only hearing air out of the dipstick tube or PCV, throwing a shot of oil down the cyl's then run a compression test, this will tell you if the rings are going. if the comrpession numbers go up substantially, you have ring issues. While i cant say ive seen many diesel rings go bad, its still possible.

 

[OregonDMAX]

That should be fine. you just gunna need to make sure each cyl you test is at TDC on the compression stroke. if your finding your only hearing air out of the dipstick tube or PCV, throwing a shot of oil down the cyl's then run a compression test, this will tell you if the rings are going. if the comrpession numbers go up substantially, you have ring issues. While i cant say ive seen many diesel rings go bad, its still possible.

kinda what i thought. i might as well pull all the glowplugs again, do the leakdown test and do another compression test (i should have done a second compression test with a shot of oil but i wasn't thinking about it at the time)

whats a proper psi to do a leakdown test without blowing any seals out

 

[Chevy1925]

kinda what i thought. i might as well pull all the glowplugs again, do the leakdown test and do another compression test (i should have done a second compression test with a shot of oil but i wasn't thinking about it at the time)

whats a proper psi to do a leakdown test without blowing any seals out

10-20psi should be plenty for you to listen for a leak. pop the cold side intercooler tube off the y-bridge for you to listen out of, popping an up-pipe off the manifold would help in listening for exhaust valve leaks, then pop the dip stick tube out or put the pcv hose away from the y-bridge and listen there for lots of air. Finally, do the final look arounds like the coolant bottle looking for air bubbles. you dont sound like you have any HG issues but it dont hurt to glance at it.

 

[OregonDMAX]

10-20psi should be plenty for you to listen for a leak. pop the cold side intercooler tube off the y-bridge for you to listen out of, popping an up-pipe off the manifold would help in listening for exhaust valve leaks, then pop the dip stick tube out or put the pcv hose away from the y-bridge and listen there for lots of air. Finally, do the final look arounds like the coolant bottle looking for air bubbles. you dont sound like you have any HG issues but it dont hurt to glance at it.

thanks for all the good information, i will do a leakdown test and report back.

starting to get worried that its going to be expensive.

 

[Andrew]

any news?

 

[OregonDMAX]

its snowing and 18 degrees and i don't have a garage to do the leakdown test in. so im going to have to do it next weekend when it warms up.

althought i did double check just to make sure that i didnt also have a cooling problem, upper radiator hose this morning was soft, i could pinch it pretty easy. the only things i have replaced on the motor were a slightly seeping waterpump and two stuck open thermostats. could driving around with such cold operating temps cause an issue inside the motor, it was about 2 cold winter months before i got my CTS and saw that i was barely getting 140* max cooling temps before i changed the thermostats.

also did the paper towel test on the oil from the dipstick and there is no fuel saturation in the oil so at least i have my other bases covered.

as soon as it warms up i will be back out to finish testing and report back

 

[workin' diesel]

Mine smokes out the breather too. If I take the fill cap off when it is warm it will do the same thing. I try not to let it bother me. At almost 190,000 something has to start wearing out.