Ask an expert


I took my 2001 Hyundai Grandeur in for a wof today and one of the things it failed on was excessive smoke coming out of the exhaust pipe which is grey in color. They recommended I get an oil change and replace it with a thicker oil which I did and there's still no improvements so I took it back; They then said I should take it to a mechanic and get the breather system looked at which I'm assuming is just the crankcase ventilation system.
Could this be a possible cause of the excessive smoke? I haven't had any problems that I'm aware of with excessive oil being used in the car either. But I couldn't find any information about the ventilation system causing excessive smoke out the exhaust pipe so I'm not quite sure but I'm hoping this is it rather than needing the engine replaced like they mentioned also. What other reasons could there be for the excessive grey smoke?


Hi there,
There is not much it can be, black smoke from too much fuel, grey/ white smoke/ mist could be burning coolant (blown head gasket), blown turbo (on turbo engines) or just condensation from moisture build-up in the exhaust, blue smoke is burning oil- which can be from old worn valve-stem seals, worn piston rings, or a blocked crank ventilation valve (PCV) are the most common.
A mechanic would need to check which kind of smoke it is in order to find the best method to slow it without spending too much money- if it is the engine, it may not be worth repairing because of the vehicle age and current value.