I recently bought a 2008 Saab 9-5 wagon with roughly 50,000 miles on it.
The issue is that when I turn on the heater, after about ten minutes of driving, the cabin begins to smell like a poorly-ventilated auto repair shop.
The weird thing is that I am able to stop the smell by turning on the defroster. Switching back to the heater brings the smell back.
I don’t smell it when both the heater and the defroster are off, and I haven’t checked to see what happens when I turn on the AC.
The mechanics at the used Saab dealer who sold me the car are pretty experienced, but can’t solve the problem.
They first thought that it might be a grease deposit on the engine block that smells when it heats up, or that there is something dripping onto the engine block and burning, but cleaning the underside of the engine didn’t make the smell go away (and doesn’t explain why the smell goes away when the defroster is on).
We did discover that there is a leak in the reservoir for the windshield wiper fluid.
The mechanics at my local Saab dealer haven’t ever heard of such a problem.
Any ideas about what is going on?
(or any ideas about where to find help)