About every 2-3 days I can sense burnt coolants smell through my AC. My car was in the past overheated, but seemed to be ok. I overhauled the cooling system (water pump, thermostat, hoses, tank, sensors) except the radiator. What could be causing this burning smell? A hole in the radiator that may be allowing seepage of coolant?

I think I have noticed that the burnt smell comes usually after me going on a curve, so maybe there is an area where coolants gets tipped on some hot area of the car and creates that smell/

Could it be something more serious? Head gasket issues?

Car has 117k, 99 E 46 323

If you smell it in the cabin with the windows closed, it's either:

1) coming through the external vent - unlikely while you're driving, since the vent is right by the windshield, which should be a constant flow of ambient external air, not air from the engine bay

2) leaking from the heater core, or hoses/connections to the heater core.

About every 2-3 days I can sense burnt coolants smell through my AC. My car was in the past overheated, but seemed to be ok. I overhauled the cooling system (water pump, thermostat, hoses, tank, sensors) except the radiator. What could be causing this burning smell? A hole in the radiator that may be allowing seepage of coolant?

I think I have noticed that the burnt smell comes usually after me going on a curve, so maybe there is an area where coolants gets tipped on some hot area of the car and creates that smell/

Could it be something more serious? Head gasket issues?

Car has 117k, 99 E 46 323

Not serious. Had the same problem with the wife's 323i. If you have over 60K miles on it, its a high probability that its the valve cover gasket. Her's practically carbonized which allowed oil to seep through and leak onto the manifold causing the burnt smell periodically.

I put in a new one...never had that burnt smell again. Easy DIY fix, but would recommend getting a Bentley manual to walk you through it if you haven't done it before. Will take you about an hour...plus or minus a few beers.

So, the oil that was burning on the exhaust manifold smelled like burning coolant, not burning oil? Interesting.

Anyway, you can visually inspect for this; look on the exhaust (passenger) side of the valve cover, it's pretty easy to see if it's leaking down the side of the aluminum cylinder head.

So, the oil that was burning on the exhaust manifold smelled like burning coolant, not burning oil? Interesting.

Anyway, you can visually inspect for this; look on the exhaust (passenger) side of the valve cover, it's pretty easy to see if it's leaking down the side of the aluminum cylinder head.

Sounds weird I know. Maybe the synthetic oil when burning has a similar smell. Maybe you have a small coolant leak too and are getting mixed smells...oil and coolant.