I have a '95 Civic DX that I purchased about 7 months ago. Now that it is cold and I have the windows up all the time, I am regularly noticing smells of gas or exhaust while I am driving. I am assuming that it is from the other cars on the road, due to the fact that it is not always present. Is there something that I should check for that would allow the smells in? It occurs with the air on or off and with the recirculation control on or off. It's not overwhelming, but it is certainly a nuisance. I am guessing that this is a fairly common occurrence once a car gets a little older, but I'd like to try to correct it if I can. Thanks,

Andy

 

Is it a relatively high mileage Civic? I had an old 92 Civic and a less old but high mileage (250K) 2000 Civic that had a similar problem. In my case, the header had cracked right down the middle due to age and wear. That allowed exhaust to be picked up through the vent intake and then get recirculated into the car.

To check if this is your problem too, pop the hood (with the engine COLD) and take the heat shield off your header. It's just two 14mm(?) bolts, but they might be rusty and could possibly break, so be careful. You'll have to swing the heat shield to the side, as it will not come completely off without removing the o2 sensor. (That's more work than is necessary.) If you have this issue, it will be very obvious and will most likely be cracked in the middle, right through where the o2 sensor goes.