Intermittent plumes of smoke

[Bert]

Increasingly frequent on my car is for the engine to smoke through the exhaust. I changed the PCV valve yesterday (seemed like a good idea) but that hasn't rectified the problem. Are there vents or lines that might plug up or pressurize and are there other avenues for oil to get into the combustion chambers on an irregular basis? This has been bugging me for the past 2 weeks and I'm not so sure that changing the valve seals (the motor has for a long time smoked a bit on start up) would address this.
The other day I even noticed a dim glow in the retrofit tach cluster dash which corresponds to the location of 'check engine' light (that particular cluster has no print etching in the space between the 'belt' and 'r-defog' symbols). But even that is so far dim and intermittent. In every other respect the engine runs good.
I have a spare lo-mile B3 engine but it's getting cold outside and I'd just as soon not contemplate a frivolous swap if I don't have to.

Anyone out there experienced anything like this? Anyone got any ideas? Compression checks wet and dry have been good in the past but I can take some time to perform another.

[GenevaDirt]

I would say the seals are just getting worse and letting more oil through then before....especially if the comp test checked out.

What year and carbed or EFI?

[WmWatt]

"it's getting cold outside" could mean condensation rather than unmburnt fuel. Does the exahaust smell oily? Is the oil level on the dipstick steady?

[Bert]

It's oil for sure. What bugs me is that it is an irregular thing that is becoming more common. Today for instance it behaved fine (except for the puff of smoke on start up (which is valve seals)). It's a 300,000km EFI car from 93. I'm leaning towards a blockage somewhere that unnecessarily pressurizes and forces oil into the system but this whole business is a new one on me.

[WmWatt]

An chemical cleaner might help. Then again its risky using it on an older engine where carbon buildup is actually a sealant. You could try an engine oil forumlated for older engines.