I HAVE A MAZDA MX6 2.5 V6 ENGINE WHICH IS VERY POORLY AT THE MOMENT. FIRST OFF ALL ONE OF THE SPARK PLUGS WAS NACKERED SO I ENDED UP CHANGING ALL OF THEM AND THE LEADS, THE CAR RUNS FINE TICK OVER IS SWEET AND THE DRIVE IS AS NORMAL, APPART FROM WHITE SMOKE POURING OUT OF THE EXHAUST!!! I HAVE HAD A COMPRESSION TEST DONE ON THE ENGINE BECAUSE SOMEONE SAID I MAY HAVE DONE A PISTON AND SCORED THE BORE WITH A BROKEN UP SPARK PLUG. THE COMPRESSION TEST WAS HEALTHY AND I JUST WANT TO KNOW IF YOU HAVE ANY IDEAS. IVE OWNED THE CAR OVER A YEAR JUST HAD A KIT PUT ON AND 18" CHROME WHEELS AND NOW THIS ITS EMBARASSING TO DRIVE !!!!!!!!!
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No need to shout, we're right here.

White smoke means coolant, blue smoke means oil.

Given that it's white smoke, I would initally suspect blown head gasket, and coolant is getting into the cylinders. However, with a good compression test, it makes me wonder if coolant is getting into the airstream somewhere before the valves. Could still be the head gasket though.

Questions...Has the car smoked for the entire year you've owned it, or is it something new? Did it overheat at all? Is the smoke worse at engine-start, or the same even after it's warmed up? Are you confident that all 6 cylinders are firing?

Mark in MA

 

hi sorry for shouting!!! lol no the car has never smoked before like it is now. it does smoke on start up, tick over and driving especially when changing gear or drop in revs. yes it is running all cylinders, and the car drives sweet as normal, no missing or anything. thanxz michelle

 

i have been told by a man that it is actually blue smoke !!!!!!!!!! sorry im female please forgive me !!! lol

 

Blue smoke means oil, so the two major ways oil gets into the combustion chamber is from valve seals or piston rings. Bad piston rings should fail the compression test, and you should see some blowby. Blowby is pressurizing of the crankcase from the piston rings not sealing adequately. Foamy oil on the dipstick or oil soaked PCV valve and breather may indicate blowby. I'm guessing valve seals, especially with smoke at startup and drop in revs.

Check your coolant for evidence of oil in it (oil floats in coolant). And check your oil for evidence of coolant in it (possibly swirls of lighter brown slurry in it). Those would both be indications of blown head gasket.

Since you're burning oil, definitely check the dipstick more frequently to make sure you don't run low.

Mark in MA

 

Yes they're right. The white smoke is caused by the coolant that came out of your car's tail pipe. It could be possible that the water splashed up onto the exhaust pipe. However the coolant must not affect the radiators, or else it could mean serious trouble.