My 2007 Volvo S40 T5 has white smoke coming from under the hood from time to time but usually in city traffic. I cannot replicate the problem and am confused and concerned.
Is it smoke or steam? If it is steam, you have a coolant leak somewhere. If it’s smoke, you could have a small oil leak and ther oil is dripping on the hot exhaust.
What does it SMELL like? If it’s only in city traffic, it may be a coolant leak. Open the window and smell it.
Yes you should be concerned. before you go anywhere check the anti freeze level or stop by your oil change place for a check. Most probably steam from a bad hose or connection, if you are low on coolant prime suspect 1. Get a good mechanic to look, do a pressure test on the radiator, look for oil leaks or tell you why the problem is happening. If it is still under warranty have the dealer look it over, with previous thoughts in mind. Do you have a temp guage and notice any fluctuation?
Apparently the white smoke was caused by polin and other particles caught in the radiator. When mixed with rain, water or dew and the radiator heats up, the combination is released as a white smoke. Who knew!? At least it is not a defect or serious hazard. The problem was cured by using pressurized air to clean out the radiator coils in front of the engine. Thanks for the other suggestions!