I just looked at a Montero sport with the 3.0 engine, 6g72? and was happy with everything but the blue smoke I saw as I followed it. It emitted a bit of blue smoke on acceleration, not a big cloud but enough to easily see.

According to the owner the car is not driven often. On inspection I found stickey oil in the filler neck and the owner says he adds some stp at each oil change. Claims it burns no oil between changes at 3k miles. Found no indication of soot on the rear of the car and the tailpipe looked ok. Car has 142k mi and looks ok otherwise.

Do these engines burn a little oil after they have been sitting? Is it more likely to be blow by from rings or bad valve guides and or seals?

I like this car and it's condition other than the blue smoke but don't want to end up having to rebuild the motor. If it is seals I might be able to justify that it the price would get better.

Should I try to investigate or run away quickly?

 

Rings most likely. Oil seaping up from the crankcase past the rings.

 

Really?

Any other opinions?

 

Also could be valve steam seals, you wont know for sure untill you do a compression and leak down tests.

 

I would suspect valve seals as it is only after idling for a bit and only a puff. It's a moot point however as I found another I like better.

 

My vote goes for valve guides and seals. The bottom end of these engines are bulletproof, whilst the guides/seals are their major weak point. Minor chance that its the bottom end, especially given the mileage. Get the vehicle thoroughly inspected and negotiate a price drop, taking into the account the cost of repair.

 

SKIP IT.

Do not buy it. There are more cars out there with viewer problems. blue smoke

I had been buying used cars I never seen a blue smoke coming from any cars I bought.