05' GT, W/Series III Smokes

[hd20ts]

I have a 05' Grand Prix GT with 57,000 miles. It has a SERIES III Engine and I bought it used about 45 days ago. I ran a carfax report before buying it as it was a rental car with a major automobile rental firm. It looks like ALL service has been done in a timely manner and on schedule. From the outside looking in, the car is mint condition, very very clean. about the third day after buying it I noticed it was beginning to smoke leaving stop lights going through town. Of course I bought the car as is, but I called the dealer and got the run around "as-is" talk. Now as time goes on, the smoking is getting worse. I have noticed though, it will "NOT" smoke if the car does not reach a certain temp. And sometimes I can drive it for an hour and it wont reach that temp, thus "NO SMOKE" ?? But the instant it reaches that magic mark, it bellows a horrible plum enough to choke anyone behind me. I have never heard or seen the fans run. I have let it idle and come up to temp. just to see if they were coming on. They didn't. I have actually thought about putting in a cooler themostat in just so it won't reach that dreaded mark??.. I just find it hard to believe that a state of the art engine, with 57k miles, even if it was ran hard, would be smoking like this. Any help would be very much appreciated.

[BNaylor]

Welcome to AF.

Thats a lot of mileage for one year. It doesn't make any difference what year or make car it is but the basics apply. How is the oil consumption rate?

Check things like the PCV valve first to rule out crankcase ventilation. AC Delco part number: CV892C.

In a worse case scenario you could have flaky valve guide seals or piston rings but that is hard to imagine even with 57K miles although not improbable. Ultimately you may want to consider running a compression check of all cylinders.

BTW - What color is the smoke?

[hd20ts]

I agree It is alot of miles.That's what's baffling, the oil comsumption. When i first noticed it, (It was Full When I bought It) It used a qt the first 15 days. Since, It hasnt used a qt in 30. Actually not even a third of a qt. The color of the smoke is a light blueish gray, and thanks i will go check the pcv valve. The thing just runs to good. no rattle, no loss of horsepower?? but the valve guide was my first thought also. is there really an additive that can help that or are they all more bull?...someone said lucas oil was the only one worth using???

[BNaylor]

I'd hold off on any engine additive until you complete troubleshooting. But it definitely sounds like it is burning oil. Its a shame for being an '05 model. Good luck and let us know what you find.

[hd20ts]

I found the pcv valve, it seems ok, but there is a hole directly to the right in the housing where the map sensor goes in and it is above the pcv valve. the hole does not look like a typical oiler hole as it does not looked machined and is about the size of an pencil eraser. it is very jagged