Smoky 1992 Cummins Diesel

[Randm Musing]

Smoky 1992 Cummins Diesel

Due to some unfortunate circumstances in my life I have become homeless. I just became interested in the possibility of living in a motor home. I found one that I like and could possibly afford, but it may have some problems.

It is a 1992 class A with a Cummins diesel pusher, with 75,000 miles on it. For a diesel, that should be just getting broken in. It seems to run well (I did not get
to take it for any kind of test drive yet,) but I had the dealer go through the gears,
and there was nothing noticibly untoward, but when it had been running for a while
there was quite a bit of blue smoke coming from what I believe to be the torque
converter. The exhaust coming out of the tail pipe was clear.

I have misgivings about any kind or source of smoke, but wanted the opinions of more knowledgeable and experienced MH'ers.

Thanks for any information.

Charles.




E-MAIL CONFIDENTIALITY NOTICE: There is nothing safe or secure about the Internet or e-mail.
Do not put my last name, my telephone number, my physical address or any account number of any kind in any e-mail message. The contents of this e-mail message and any attachments are intended solely for the addressee(s) and may contain confidential and/or legally privileged information. If you are not the intended recipient of this message or if this message has been addressed to you in error, please immediately alert the sender by reply e-mail and then delete this message and any attachments. If you are not the intended recipient, you are notified that any use, dissemination, distribution, copying, or storage of this message or any attachment by any means is strictly prohibited.

[FleetMan]

The blue smoke from the torque converter area is probably engine blowby coming out the slobber tube - crank case vent. They all smoke to some extent. There are tests which can be done to determine if the amount of blowby is within normal limits.

If everything checks out OK and you buy the rig, you should consider an easy modification to preclude that blowby picking up dust and dirt and clogging your radiator and intercooler.

[Randm Musing]

Thanks. I appreciate all input.

[Mike Canter]

The Cummins B5.9 diesel which it most likely has had a mechanical injection system so they will show black smoke out the exhaust at wide open throttle or when they shift gears. They should not be blowing blue smoke out the slobber tube or from the torque converter or the exhaust. Blue smoke is burning oil. It is common to get some blue smoke out the exhaust when they first start up especially if cold but it should clear away once it warms up a little. Now that could be caused by engine oil or transmission fluid dropping onto the exhaust pipe or oil dropping down out of the turbo housing which is a bad sign and means the seals maybe gone in the turbo which is somewhere in the $900-1200 range for that motor to fix. You need to take a better look and see where the smoke is coming from. If it is coming out the exhaust pipe then that is another sign the turbo seals maybe gone. The other thing to check for is that year was the crossover years for the Allison transmision switching from a 4 speed to a 6 speed. The 4 speed will drive you crazy because the engine rpm will always sound too high and the accelaration and gas milage will be down. The good news is that engine will get you about 10+ mpg while towing on a level road and 11+ when not towing.

[Randm Musing]

M. Canter

Very good information. Thank you for sharing your knowledge. I think that I had better pass on this one. I simply can not take on a "fixer upper."

Congratulations on making military retirement. Five years was the best that I could do.

Charles.