Bluish/white smoke at start up

[InitialDerek]

98 Maxima (155k mi) - I have recently noticed a bluish/white smoke coming from the tail pipe after starting the car. I have noticed it doesn’t happen each time. It usually occurs after it has sat overnight or for a long period of time. Any ideas on what the problem may be would me greatly appreciated.

Thanks

[maxhopper]

It could be numerous things. Try doing a compression test on your car. This would either verify or eliminate the most serious problem. The compression should be 185psi. If it is below 142psi, you have internal problems.

[InitialDerek]

Thank you very much for your response. It seems like it smokes when I use Castrol oil. Is it possible that certain motor oil brands can make a difference with engine compression? Thanks again

[maxhopper]

Highly unlikely. My personal opinion...castrol is junk. It seems that it breaks down and causes varnish to accumulate more quickly than other petroleum-based oils. I only use Mobil 1 synthetic in my cars. Here is a link to an informative thread. zerothread?id=112537You can also do a search for "oil" as the topic has been discussed numerous times.

[NISTECH]

you should also check your base idle and make sure its not too low. This usually occurs in cold weather and not during the summer. But when the air passeges become "congested" with carbon build up the base idle is effected and will cause a slightly richer then normal condition on start up. You can perform and induction cleaning to see if that helps or bump the idle up when doing the base idle check if too low. This is done by disconnecting the tps with the car off, starting the car and observing the idle, I believe your base idle spec is in the neighborhood of 700 rpm. Your car must be warmed up to operating temp prior to doing the procedure. I suspect you will find your base idle is down around 450 to 500 rpm .

[InitialDerek]

Thanks for the help guys. I'll let you know what happens.