Recently I have been seeing smoke from the engine compartment of my truck. Took it in to the dealer had the oil and fuel filter changed, and PCV valve changed. I'm still having blow by. The truck runs awesome as it always does. I have noticed that my oil pressure is higher than normal though. The brownish smoke is coming out of the weep hole in the crankcase and just a tiny bit of oil is coming out as well. Not enough to drip in the driveway. My motor is covered in brown oily dust as well. My balance rates are all at 2.5. Truck has just under 177k on it. Anyone have an idea of what to look at next? Thanks for any input
2003 LB7 blowbye problem
- Thread starter HASTINGSRJ
- Start date
What weep hole are you referring too? Take your oil fill cap off and set it upside down on the fill tube and see if it bounces from pressure. If you are having excessive blow-by it is time for a cylinder compression test and a leakdown test to check cylinder condition before going futher with diag.
The hole on the crankcase, bottom right side of the motor. I will try the oil cap test tomorrow. Thank you
There shouldn't be a hole in the crankcase down there...
On the LB7, there is an oil separator for the PCV system in the right accessory mount, and it has a drain that goes down to a nipple in the block to return oil collected from the PCV back to the crankcase. There is supposed to be a hose on that. See the attached pictures.
On the LB7, there is an oil separator for the PCV system in the right accessory mount, and it has a drain that goes down to a nipple in the block to return oil collected from the PCV back to the crankcase. There is supposed to be a hose on that. See the attached pictures.
Attachments
Thanks for the info Dave. My truck will be going back to the dealership this week so my buddy can look at it again. Waiting for the rain to pass so I can drive my car to work.
A little blowby out the oil fill cap is OK. But there shouldn't be much/any pressure.
Do the test MadMax17 said: with the truck running, take the oil fill cap off, flip it upside down, and set it on the oil fill tube. It should not be lifted off by the blowby (it should just sit there and not move).
Do the test MadMax17 said: with the truck running, take the oil fill cap off, flip it upside down, and set it on the oil fill tube. It should not be lifted off by the blowby (it should just sit there and not move).
I did the test with the oil cap, it's moving around and not staying on the full tube while the truck is running.
That sounds excessive then. I'd say it is time for a compression test, and if that doesn't indicate a problem, then a leakdown test.
Sadly, to fix it, you will almost certainly have to pull the motor. So you could just pray it doesn't get worse, and run it. It might last for years and years as is. These motors are pretty tough. Just keep an eye on it to see if it gets worse or not.
Sadly, to fix it, you will almost certainly have to pull the motor. So you could just pray it doesn't get worse, and run it. It might last for years and years as is. These motors are pretty tough. Just keep an eye on it to see if it gets worse or not.
Really unlikely, but you can pull the PCV apart and make sure. You don't even have to take the valve covers off to do that, but be extremely careful not to drop one of the screws inside the PCV, or it will end up in your valvetrain, or worse.