'03 crankcase breather smoke at idle with pacbrake engaged

[NWest]

Today I started my '03 to get the engine warm for an oil change. I turned the pacbrake on to hurry up the warm up time. After several minutes, I noticed smoke billowing up from the wheelwells, and found that it was coming from the crankcase breather. When I switched the pacbrake off, the emissions from the breather tube diminished.

Is this cause for concern? I haven't noticed any performance issues (towed our fifth wheel 5500 miles in June without incident). The drained oil looked normal, no sign of coolant or emulsion.

 

[AH64ID]

Running the exhaust brake on a cold motor will push combustion gasses past the rings into the crankcase. I've seen the results of increased soot on UOA's from doing it.

My guess is that this is what was happening, thou I've never seen it that extreme.

 

[cerberusiam]

Yeah, using an EB to warm an engine is maybe not the best thing to do when it is pushing combustion past the rings. Check you blow by at 1200-1500 rpms, if you have significant discharge form the oil cap you might have some broken\stuck rings or worn cylinders.

 

[sfpcservice]

My truck had bad blow by and it turned out to be a cracked ring on #1. Ran just fine and I must have put 20 or 30k miles on it running that way. I got really lucky it didn't fail or tear up the cylinder real bad:

 

[NWest]

Thanks for all the responses. I'll check the blowby again next chance I get.

 

[B.G. Smith]

could also be some coming up around the exhaust valve stems if you have lots of miles. bg

 

[NWest]

After work today I started the truck again (this time without the pacbrake engaged) and watched for crankcase emissions from the oil cap. Even at dusk, looking into the sun, I didn't see anything significant at idle through 2000 rpm. I'm hoping I can chalk this episode up to ignorant use of exhaust brake. Fingers crossed.

 

[2004HPCR]

If your piston rings dont have blowby issues, the problem could be your turbine seal. When I rebuilt my turbo I installed a gapless turbine seal, I noticed a lot less coming out of the breather after that.

Also, your exhaust valve seals might be letting gasses escape into the crankcase as well.

Just a couple of ideas.