I just purchased a 2004, 5.9L with 24,000 mile on it. Yes 24,000 actual miles, like new condition! The problem I am having is at idle or at low speed after I have driven in town or on the highway (no load conditions), I smell burnt oil both outside and inside of the cab. I do not smell the oil when when driving lets say at 30 mph or higher. I have examined the engine and under the truck for oil leaks (engine and trany) and found none! I took the truck to my local Ram dealer and they could not find any problems. They indicated that the truck was like new inside and out. I have been checking the oil level in the engine and trany and do not see them dropping. There is no smoke showing at the exhaust.

Prior to this truck I had a 1998 5.9 L and never had this type of smell. The smell I have is not a diesel exhaust smell but a burnt oil smell.

What is causing the problem?

 

If it smells like burnt oil then oil must be burning some where. All I can say is really go over the entire engine with a fine tooth comb. Maybe get some leak finder that comes with dye and the glasses to see where it is leaking from.... Other then that get your nose checked..haha

 

Thank you for the suggestion, I will get my nose checked ASAP! In the mean time I will start wearing a respiratory when driving the truck!

Seriously, I have closely examined both the engine compartment, engine, and under the truck for leaks, all is very very clean. Initially I though some oil got spilled during the oil change that was performed when I procured the truck but I have driven the truck over 1,000 miles since that time and the smell still continues.

I believe the problem must be an internal problem since I see no oil leaks. Could a very small amount of oil (just a few drops) is being pulled from the engine or trany and burnt in a manner that leaves no external trace and where would that occur?

 

Whenever I change oil in my truck I get an new oil smell in the cab and out of the cab. It lasts for about 500 miles into the change, and it just comes out of the crankcase breather. That could be what you are smelling, especially in a newer engine.

 

I will check the breather!! Very good suggestion!!

 

Did you use Rotella if so that a known smell for that brand of oil called Rosmella.

 

No I did not use Rotella oil in 2004 but did in my 1998 truck. I never had the smell coming from the 1998 just the 2004.

 

The 3rd gen trucks are quite different from your previous 2nd gen...not apples to apples by any means.

I would check for blow by first, then I would closely inspect the extreme back of the valve cover and rocker box cover as these can leak down the back of the engine and "burn", but you won't easily see it. Do you know what oil is in it currently?

I would also wonder if there is something in the air box or intake tract of the HVAC system?

 

The oil that is presently being used is Motorcraft 15-40 Syn blend. I reexamined the valve cover and rocker box cover and can not see any signs of leakage.

When you ask about the air box and intake track, exactly what are you referring too on this engine and where would it be located? Are you talking about the air intake filter and the hose that leads to the engine? Can you provide a link to a schematic showing the parts you are referring to so we are on the same page? As stated I am a new "newbie" but willing to learn.

 

Since you smell it only in the cabin, check the fresh air intake of the cabin air...it might even be the fan motor dying.

Good luck.