On a couple of occassions I have noticed that if I start the car then move it a few feet, turn it off and then restart it later there is a puff of smoke for a few seconds, obviously my heart skipped a beat.. It doesnt do it at any other time. Its a 2007 XKR with 60,000 miles FSH.
Ive had older cars in the past and when it was valve seals the car smoked literally all the time on startup

Any ideas please?

 

What color is the smoke? If it's white and doesn't last long, it's probably water vapor and it's normal. A by-product of internal combustion of gasoline is water vapor, which upon shutting off the engine collects in the exhaust system. That's why you occasionally see water dripping out of the exhaust pipes of older cars. The heat from starting a cold engine cuauses the water in the exhaust system to boil out as steam vapor, which is the white smoke you see.

 

Could be extra fuel from shutting down while in whatever 'loop' is for cold start-up. Open? Closed???

 

@markva44 , Like you said… its an 07. I have first hand experience with this. But as its just at startup and the level of oil barely drops between oil changes. (does not even need .25 l) I’m not going to worry about suggesting open heart surgery yet.

Look at it as “additional lubrication”, lol.
Out of interest, what oil are you running? Car calls for WSS-M2C-913B 5W30. But, I only used synthetic. Perhaps that is why that startup puff is just starting now, at 160,000 kms.
Cheers.

 

Hi. Im using Castrol GTX 5W-30 5W30 A5/B5 Fully Synthetic

 

sure. Was that being run its entire life? Was the first oil change done at 1000kms? the second at 2500??
We have 3 situations against us: wear, tear and age.

 

The smoke was not the blueish valve seal smoke with a smell it was more grey which makes me think its the cold start cycle, as the car was cold when it happened, took it out my garage, went in the house to get my wallet then restarted, greyish smoke.

 

Check your PCValve. Change it time?

 

Burning oil has a mod distinct gray than white color. Whereas the white is more water vapor. Burning oil smoke is more persistent , whereas water vapor dissipates in the air more quickly.

 

True, but RING oil burning is persistent. If the valve guides are the oil problem, then the blackish smoke will only be on a cold start, and only for a couple seconds.

 

Sorry, I meant oil smoke does not dissipate as quickly as water vapor after exiting the exhaust.

 

Surely that is exactly what you said the first time? 🤔

Richard