Burning smell after fluid change
 

About a month ago I got all my fluids drained and re-filled. We did the ATF, both differentials, brake fluid and the fuel filter. Immediately after, I noticed a faint burning smell coming from the vents. It doesn't smell like rubber or oil or coolant. It was a bit more pungent. The mechanic thought it was gear oil but he didn't see any obvious signs of a leak. The smell dissipates when the car is stopped and idling. I also don't smell it much after doing a highway drive. I smell it mostly after doing some "city" or "around town" driving. You can't smell it from outside the car. It really only comes in from the vents when it is bringing in "fresh" air.

It is possible they spilled ATF or gear oil when doing the change but I still smell it and it has been quite a long time. It is possible they "bumped" something or didn't get a good re-seal of an o-ring or gasket. It is also possible that the timing was a coincidence and it had nothing to do with the fluid change.

If I have a leak it is a slow one as I haven't noticed any fluid levels changing or any spots on the ground. In fact, the underside has been bone dry. As some may recall, I did have a PS leak from a loose fitting that was leaving some spots on the ground and we got that fixed. I suppose some dripped fluid could have worked its way to a hot part.

But the weird thing is, I swear that it only smells after a "city" drive and it seems like the smell might be fading slowly. But it is still there and that bothers me.

Re: Burning smell after fluid change
 

The smell of ATF will permeate for a long time after spilled on exhaust. That's probably what you smell.

Re: Burning smell after fluid change
 

Check to see you have the proper type of diff dipstick. There are 2 different ones, 1 with a notch, and 1 without. If you have the type that a dipstick with a notch is meant for, and you use the other type, you will have this happen. Try hitting the "recirc" button and see if the smell is still there or not.

Re: Burning smell after fluid change
 

I'm pretty sure the dipstick is ok. The first thing my mechanic asked me to do was check to see if it was popped up and it wasn't. Before the fluid change, I had no smell with the same dipstick.

When I hit re-circ, there is no smell. It is definitely coming in from the vents.

On the fluids, I am using Redline synthetics so, if ATF normally takes a long time to burn off, this stuff is taking even longer. But why would the smell be stronger for a "city" drive and seemingly disappear after the car has been idling in park for a while?