Replaced camshaft sensor, turbo sensor, map sensor, crankshaft sensor, ignition coil, spark plugs fuel injectors and NO Service lights on dash. Car started and runs pretty good. With typical exhaust color. Returned to the car a day later rev the engine a couple of times and drove a small space. Large cloud of White smoke.
I did the glove test and it passed. No milky substance on oil cap. Doesn't overheat. I still have to change the oil and get quality spark plugs. But can it be the turbo?

 

are you consuming coolant? if so that can happen via the head gasket or the turbo seal. If it happens once in a while and only on a cold start with no coolant loss, then it may be condensation in the engine/exhaust or it could be oil dripping in via the valve seals or a leaky injector. Any oil consumption?

with the spark plugs, don't go fancy - best bet is simple OEMs from a Volvo friendly site like Tasca Parts or FCP. Check the color of the plugs when removing to see if they are a consistent tan color. Watch the oil and coolant levels over the next 500-1000 miles or so.

 

No excessive oil or coolant consumption but the white smoke did come from the exhaust. Going to test drive a longer distance but the smoke is too embarrassing to drive long distance

 

I also wanted to mention the fact that before I rev the engine that exhaust smelled rich. After putting in the catalytic converter boost cleaner, upgraded the spark plugs, the rich exhaust smell is gone, and less smoke but I did notice a minor oil drops leaking from waste gate on turbo. Is it head gasket or turbo?

 

normally running rich would throw a code if it runs rich too long. seems plausible that a leaky injector could allow fuel to drip in while the engine is off leading a puff of smoke at start up. Valve seals can do the same thing but usually cars with valve seal issues will consume oil. A quick test is to put the car in low, accellerate to high rpms and let off the gas (without the car shifting), if it puffs a cloud it means its pulling oil past the rings or the valve seals . I'd look at the plugs to see if any look wet or black

 

MissyC70
I have a C70 same problem everything that you listed I had codes po237-turbo / supercharger boost sensor a circuit low, po236- turbo / supercharger boost sensor a circuit range / performance, p0455 -evaporative emission system leak detect gross leak no flow, po335-crankshaft position sensor a circuit and the service engine light and check engine light were on.
Then I replaced the turbo charger boost pressure valve, manifold pressure sensor, map sensor, crankshaft sensor the cam sensor, spark plugs, ignition coil. I just ran the car for over 30 minutes,. Cold the car has no white exhaust smoke, No service lights or check engine light but once it heats up lots of white smoke and service light on but not constant. the light went out aft I rev the engine. All levels were fine, oil and coolant were fine. I did notice a small faint smoke coming from the back part of the engine not where I could see.
I ordered the blown head gasket tester kit and plan to test tomorrow.

 

I used boost catalytic converter cleanser, and it seems to work to clean the excess carbon out however I just noticed a couple of drops of oil that is oozing not dripping from the wastegate of the turbo. While the car is idle there is not much visible white smoke coming from the exhaust. However when I read the engine I do have smoke. The smell no comment because it's not sweet and it does not smell like oil. I have not driven the car more than a mile since this process because the smoke is a bit embarrassing. And I'm trying very hard to pass this Virginia emissions any suggestions? I have no idea if it's the turbocharger or the head gaskets.

 

I was just told by a shop that I need another engone. I don't understand because the car has no error codes.

 

Took the car to a shop to see what the oil leak was. And although I have no error codes the car has not overheated and is not using excessive oil, the shop told me I need to replace the engine. I was not given a reason why I need to replace the engine nor did they charge me the estimated $150 fee. Driving the car home it drove just fine and no visible smoke. Any suggestions?