Hey guys here is a good one for you. I have had a burnt rubber/oil smell coming through the heater for about 6 months, I also had one of my co-workers ask me about the smell too. (Same smells and his started about two weeks ago)

The only thing I can think of is something with the heater core. Maybe got something on it? Or something on the exhaust manafolds that is getting intaked through the blower? The other thing I was thinking is possibly the heater core is getting too hot, and in turn creating that smell from materials around it, but then the truck should be running a higher temp since that is where it gets it's heat from.

I am at a lose on where to start on this one. Any input would help. (Unless you say to get a new truck, because I have wanted to do that for a long while)

Thanks in advance.
Gary

 

To rule it out, either bypass it, or drain all the anifreeze and run the engine to normal temp with heater on and see if it does smell. Without anifreeze you can run it a couple mins just to see if it is the heater core.

 

I was planning on doing that when I change the rear diff fluid before my cross country trip in a month. I will be pulling a car on a trailer as well. I will also be flushing it out to make sure I have the right percentage coolant vs antifreeze.

-I was/still kind of have a problem with it using some coolant over about a month it will use about half of the contents of the overflow resevor. I think it is the intake manifold gasket leaking again. That could be some of the smell as well.