Bad pungent smell coming after the A/C runs for about 30-45 minutes.

Asked by Feb 10, 2014 at 08:07 AM about the 2004 Chevrolet Optra

Question type: Maintenance & Repair

I own a Chevrolet Optra 1.8 model 2004 Petrol. When the car runs for about 30-45 minutes a strong pungent smell comes into the cabin which smells like oil getting heated and passing through the vents or something. It is slightly chocking and irritating to the eyes.  When I checked the service guys told it is one of the wires burning when heated and disconnected one of the cooling fans. The smell has reduced but it is still there.  It is something like a chemical (coolant) mixed with burnt oil.  Please help.

4 Answers


Check under the hood, there might be a gasket that is leaking oil.


If it is coolant, maybe you have a heater core leak.

Checked possible leakage of oil from the engine on the ramp, but no leaks found. There is some water droplets in the engine bay which I think is from the a/c. The coolant was dark brown in color when inspected. Got it changed along with some dust (rust) to ensure cooling is fine. The smell is not exactly that of coolant. It is more like a mixture of burnt oil + moist dried leaves/pollen + fungus/moss + slight tinges of chemical mixed together. There is absolutely no issue with cooling and it does not come all the time. I have noticed that when I put the a/c on high and keep accelerating the moving vehicle for about 20-30 minutes and when I put the a/c to low the smell comes in more often. This is a little bit suffocating and fuming in the eyes and very irritating that I have to roll down the windows and run for some time. Further, if the a/c is kept on external flow of air (not circulating) it tends to be very less.

How can I check to find out the heater core leak?

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