Exhaust Smell in Cab

[Bugsy]

I can have all the windows up and at a stoplight I get exhaust smell in the cab and it annoys me.
Is this normal or what is the deal with that?

[More Power]

Outside air enters the cab through the grate at the bottom edge of the windshield. You could check for an exhaust leak in the engine compartment, and check the rubber seal at the rear underside edge of the hood.

Otherwise, the breeze may have been just right to bring the tailpipe exhaust forward.... Although, some like the smell of diesel exhaust. :D

MP

[tpitt]

Try putting your heater on cab air. I've also noticed the exhaust smell in both Duramaxs I have owned. It wasn't coming from my pickups, but was from other vehicles. tpitt

[jet]

This is something I have noticed and at first I thought it was exhaust.
When ever I take my truck in for an oil change I get an odor in the cab for a while after the trip to the dealer. I think they get oil on the skid plate (or somewhere) and it bakes when the engine is warm and I then get the smell into the cab. Eventually it goes away until I get the oil changed again.

[DmaxMaverick]

Jet

That odor you are smelling after an oil change is typical of many oil brands of the correct grade (C-H/I 4). Rotella is the worst, Delo is not as bad, and some don't smell at all. It is the additive package in the oil (necessary for Diesel engines) that causes the odor for a few miles after a change. Although your dealer may have made a mess under there, the odor is normal. What brand/grade of oil are they pouring in?

Exhaust smell in the cab is not normal. There may be some normal circumstances that allow it to happen ocasionally, but if it is occuring frequently under different circumstances, the dealer needs to fix it.

[Bugsy]

Well, I do all my own service work and installed a Fumoto valve with extension straight away.
I don't do any sloppy service work like the dealerships have done for me in the past. I have time and I'm really not in much of a hurry. Like I always say" I have two speeds and if the first one isn't fast enough then you probably won't like the second." The smell seems to be diesel exhaust to me. I'm not in the habit of sniffing fumes for comparison. :)
This truck kinda aggravates me at times but I'll deal with it.
Money won't buy good service either. Not for me anyway. I took my Lexus in for service and it was a mess when I got it back. Glad the free service is gone and now I can do it my way.
Anyway, I'm gonna investigate this smell more.

[silverback]

I've noticed the diesel smell in the cab on colder mornings. When I first back out of the driveway and drive down the street. It usually goes away within a couple minutes (and I don't notice it when I start up the truck in the parking lot after work) so I haven't felt the need to investigate.
Ken

[More Power]

Beginning with the LLY, crankcase gases were routed back into the intake system to be burned during the combustion process. All LB7's are vented to atmosphere, with the vent hose near the lower right front corner of the engine.

As was mentioned earlier in this thread, with an LB7, new oil gases off and can allow that oil smell to make it into the cab vent system if the air movements are just right.

The change in crankcase venting is likely due to emissions regs, but I suspect the dealers across the country also had to answer customer concerns about oil smell, and may be part of the change as well.

Routing crankcase gases back into the air intake system also coats the intercooler internally with an oil film over time. The books I've read suggest that this reduces the IC efficiency by some amount.

MP