I have done some forum searches on the above topic but wanted to post my question to see if I could come up with anything else.

When my '98 V70 (non-turbo) idles for an extended time, say 5-7 minutes, and then drive off it belts out a bluish gray smoke. The first time that I noticed this was when my wife picked me up and the car was sitting facing uphill and was sitting for about that long. The car doesn't smoke when idling just when the RPMs go above idle it blows this bluish gray smoke out, quite a bit then stops smoking. This concerned me and I thought that possibly the valve guides or seals are wearing out and causing more oil then usual to be burned. The car has around 136,000 miles and uses about one quart between oil changes, 3500-4K miles. I also parked the car on level ground and idled for 5-7 minutes, revved it up to about 1200RPM or so and it would smoke. It never smelled like oil but like a rich fuel mixture. Keep in mind that the vehicle had been driven for about 30 minutes, 20 minutes city 10 minutes highway, so the engine was at normal operating temperature.

The car was due for a timing belt and I had that done along with a thermostat replacement about two weeks ago. I asked the dealership if they could look into and they didn't notice anything abnormal and said that it was probably the seals wearing out and that I shouldn't free rev it like I was...I said to them I revved it a little...not going to 5000RPM, not even going above 2K. That kind of frustrated me as I felt they were telling me I was abusing my vehicle. Anyways, that part isn't so important. I kept watching the issue and it seemed to have stopped. Last Sunday after doing the 30 minute trip I parked the car and let it idle for the 5-7 minutes and it spewed all this smoke once the engine left idle, however didn't smoke while idling. Again, smelled like a rich fuel mixture. I realized I couldn't park where I was since Law and Order claimed the street for their trailers and I didn't want to get up at 5am to move the car I wound up driving around for another 30 minutes looking for a spot. I finally found a spot and let the car again idle for 5-7 minutes. Revved the car to 1200-1500 RPM and no smoke.

The check engine light is not on and I haven't seen it on while driving. Is it possible the cold start valve is stuck and then sometimes unsticks? Fuel injector issues? The searches came up with a possibility of the PCV. The car is running great with no noticeable lack of power. I have followed the car on occasion and did not see any smoke come out of the tailpipe. Just to reiterate, the car does not smoke when idling, and it needs to be idling for the 5-7 minutes to blow smoke out when engine is raised above idle and then stops smoking once it blows all the smoke out. Then that seems intermittent.

Thanks in advance for your help and ideas.

 

Could be burning oil.

 

Possibly, but that doesn't add up to me. Only reason is that it seems intermittent and it started all of a sudden. Owned the car for about a year and this just started. If it is burning oil wouldn't I smell oil and not a rich mixture? I am very observant and sensitive to what my car is doing. Also with following the car I didn't see any smoke from the tailpipe and on the highway had my wife lift off the accelerator and coast for awhile to create some vaccuum to see if it could draw some oil in. No smoke at all.

 

I would check the vent system. Since it is a Non-turbo it is easy to check the flame trap. It is in the induction hose just before the throttle body.