Diesels on Propane
Q. I read an article in a four-wheel-drive magazine about propane injection for diesel engines. It made this sound like the best thing for diesels since sliced bread. It is supposed to safely provide more power (it pegged the dyno they were using), more fuel economy and better engine life. It does sound like just the ticket for my ’92 Dodge with the Cummins that I use to pull my fifth-wheel trailer. Of course, they didn’t mention anything about price. It might be cheaper to buy a new truck. What do you know about this technology?
— C/P. R., Arlington, Washington
A. Propane injection into diesel engines has been around for a while, and it does have some significant benefits. The propane burns very cleanly and puts out a lot of power. However, there are caveats. An add-on system like this could cause warranty problems on vehicles that are still covered.
When you boost the power that much, you may find some of the weak spots in your drivetrain. The pre-1994 Dodge diesels have either a five-speed Getrag gearbox or a three-speed automatic. These both can act like a fuse in the “circuit” between the engine and drive wheels.
Cummins Crankcase Chagrin
Q. I have a 1996 Dodge one-ton 4WD pickup with a Cummins diesel, 4.10 axle and five-speed transmission, with which I pull a 32-foot fifth-wheel trailer that weighs 9,000 pounds. At about 13,000 miles I started smelling something like burnt oil out of the road draft tube, and the truck began using about two quarts of oil every 3,000 miles. Everyone, including the Dodge dealership, seems to think there is something wrong. But, since the dealer can’t find a problem, the technician says it’s normal. The dealer also ruled out the turbo. I cut open the oil filter, and I can see nothing unusual inside. Any suggestions?
— B.P., San Jose, California
A. Excessive blow-by fumes coming from the crankcase via the road draft tube, combined with higher oil consumption, are possible signs that some of the piston rings are not sealing well. If your Dodge dealer can’t figure it out, take the truck to an authorized Cummins dealer for diagnosis, who is probably more familiar with this engine.
I suggest having a compression test done, followed by a leak-down test on any cylinders that are below specs. Your warranty is through Dodge, so you may have to pay for this diagnosis. But if the Cummins shop discovers a problem, have the results written down and take the paperwork to your Dodge dealer. If Cummins finds a problem that needs to be repaired under warranty that the Dodge dealer missed, you should request and be able to recover the cost of diagnosis through warranty channels.