I have a 2001 volvo S40 turbo. I had white smoke coming from tailpipe and in the egine compartment. codes were reading for bad wires and ignition coils. after replacing coils and wires, someone said t

WHITE SMOKE SOUNDS BAD COULD POSSIBLE BE A HEAD GASKET FAILURE, GET A COMBUSTION GAS TESTER AT AUTOZONE, CHECK FOR COMBUSTION GASSES IN THE COOLING SYSTEM.

Get a scanner from IPD for $80 and it will tell you what you need to do.

Yes that can be a problem. i had this happen to my 04 Volkswagen Passat. A bunch of steam and blueish smoke came from the exhaust. The problem was that the coolant seal in the turbo was bad and it was leaking. I had to keep putting coolant into the holding tank. Had the seal fixed and that fixed my problem!

Hello
When the service engine soon light (Also called the check engine light or engine management light) is turned on this is to alert you to the fact that Powertrain Control Module (computer) has detected a failure somewhere in the systems it controls you may not feel any difference in the way the engine runs, this can be the transmission or the engine or emission system, there are fault codes set in the modules memory for these faults. What needs to happen now is to have the powertrain control module scanned with a special tool called an OBD2 electronic engine control scanner or a OBD2 code reader. Once the code(s) are read then you must perform the diagnostics for each code and make the appropriate repairs based on the findings of the diagnosis that was performed, this is called doing "Pinpoint" testing.

If your smoke is coming out of the tailpipe......White smoke usually means that water or antifreeze is being burned by your engine, blue smoke is oil and black smoke is fuel ( too much fuel) . If it is coming from under the hood you need to figure out where it is coming from.

Hi there:Black smoke is caused by excess fuel that has entered the cylinder area and cannot be burned completely. Another term for excess fuel is "running rich." Poor fuel mileage is also a common complaint when black smoke comes out of the tailpipe. Black smoke out the tailpipe is the least cause for alarm. Excess fuel will usually effect engine performance, reduce fuel economy, and produce a fuel odor.
How did the fuel get into the cylinder in the first place? Some of the causes of excess fuel are a carburetor that is out of adjustment, a faulty fuel pump, a leaky fuel injector, or a faulty engine computer or computer sensor. If black smoke is present, check the engine oil as in the white smoke example to make sure excess fuel has not contaminated it. Do not start the engine if a heavy, raw fuel smell can be detected in the engine oil. Call your mechanic and advise him of what you have found.
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cracked head or gasket.

Water in combustion chamber makes white smoke--suspect that the head gasket is leaking water into the chamber. If oil leaking around turbo, it may have a bad bearing and bad oil seal. Check waste gate valve and control.

think you may have blown your head gasket ( turbo pushing too much boost)

check to make sure the turbo oil return pipe is not clogged. if it is pressure will build up causing oil leak through seal causing it to smoke.