CarTalk.com Best of Deals Car Reviews Repair Shops Cars A-Z Radio Show

Am I endangering my child's life? Burning Oil/Exhaust in a 2003 Passat

My 2003 Passat has a noxious smell when I pull up to a parking space or sometimes when I stop at a light. It smells like burning oil or exhaust, but not all the time. The repair shop has replaced the oil pan, which was dented (by my 18-year-old son), replaced axle seal, and have replaced a broken and leaking PCV hose, but that has not solved the problem, and the don’t know what else to do.

I’d love to know if anyone knows how to fix this problem and also if you could tell me if you think that letting my son drive the car with these fumes is harmful.

Thank you so much!

Doug

I’m guessing one or both of two things happened when your son dented the oil pan: Oil splashed on the exhaust pipe and is being slowly smoked off, causing the smell and/or (more seriously) he bashed the exhaust at the same time he bashed the oil pan and you now have an exhaust leak. This is more serious because if enough of it gets into the cabin it can cause CO poisoning.

I’d Have The Underhood Area, Particularly The Engine/Transmission And Fluid Lines, Inspected For A Leak Of Fluid Or Exhaust.

I’m thinking that fluid (probably engine oil or transmission fluid) is being deposited on very hot engine parts (probably exhaust system) and burning/vaporizing. Sometimes the problem is as simple as a leaking valve cover gasket, for example.

At any rate, exhaust leaks are dangerous because of the carbon monoxide. Fluid leaks are dangerous because of potential fire.

If there’s some fluid left after the repair then it should all burn off in a short time and the fumes should end. If not then you may need a second look from another competent mechanic.

I’d want to know what’s going on before letting anybody drive it.

CSA

Is the odor stifling? Has the odor diminished since the repairs were made?

It is impossible to guantify the odor but myself and many others have, despite efforts to ventilate the shops, spent a great deal of our lives in a daily routine of inhaling the byproducts of internal combustion engines with no apparent ill effects. Anti-freeze in exhaust is particularly noxious to me, though.

Get a carbon monoxide alarm. A home unit that operates on batteries might work for you. Here’s an example:

Carry it with you in the car and see if the alarm ever goes off. You might look at at stop signs or traffic lights to see if it changes while you are stopped.

If you are losing fluids, you should see a fluid levels drop.
Are you seeing smoke out the tail pipe? What is the color of the smoke?
You could have a bad cat converter- does your exhaust (car’s) smell of chilli beans?

As CSA mentioned, a leaky valve cover gasket could be the problem as well as leaking cam seals and cam chain tensioner seals. It would help a bit to know what engine you have but cam and cam chain tensioner seals commonly leak, especially the semi-circular seal that shrinks with age. When I say cam chain tensioner, I’m not referring to the timing belt in the front of the engine but the cam chain at the back of the head.

Have a shop hook up an evap/smoke machine to the tailpipe to check for exhaust leaks.
I’ve used this method quite often. After filling up the exhaust system with smoke, the leaks will show themselves soon enough. I’ve found exhaust manifold flange gaskets and exhaust manifold gasket leaks this way.