Anyone get smoke coming from around oil filler cap?

[greglilley]

I've recently noticed a faint, blueish smoke coming from my oil filler cap when reving the engine (and maybe a little at idle). I don't recall this happening when I bought the car about a year ago. I put a new cap on, but did not run the engine to see if it was better and now I'm out of state again.
The only thing I've changed in the PCV system is the PVC valve (new ac delco). Could clean the old one and it'd probably work too, but do I have some kind of pressure buildup issue? No blue smoke out the tailpipe, just the oil filler cap. What do you guys think?

[RedBird64]

Having the smoke in of itself is not unusual, even a brand new car will do it. The quantity is really the question.
If it doesn't use an inordinate amount of oil (390's always use some oil) and doesn't smoke out the tail pipe, I wouldn't worry about it.

Scott

[sseebart]

If your car has a PCV system, you might check that it's not clogged. Otherwise, if the smoke bothers you (and it can create a mess) you could plumb the crankcase breather to the air filter.

I found a breather cap with a nipple on it, then attached a length of hose to direct the "smoke" down and under the car, sorta like the old road draft tubes.

~Steve

[RedBird64]

I used to wrap a shop rag around mine and just leave it there. Sure beat having oil run down the front of the eng all the time.

[greglilley]

Yes, I just saw one of those caps with a nipple on it, Steve. Then it all started coming back to me from my 289 Galaxie 500 days (my first ride, had one of those too with home-made EPA approved down-hose, haha).
Unfortunately, I already bought a "chrome OEM" one from "Joe parts house" up the street (NOT). At least I can see the filter material in the cap, couldn't see any 'hairy stuff' in the original cap. We've not started the car to see if it made a difference (I'm 2 states away, so I'm trying not to ask family for too many 'car favors').

The perplexing this is that when I purchased the car last Jan., I don't recall this amount of blow by coming out up top. I only replaced the orig. PCV valve because I had one handy and we were 'right there' doing vacuum stuff. Considering cleaning the old one and re-installing to see if there's a diff.

Just rebuilt my 4100 and she's REALLY Purty now and purrs, so don't think I'm gonna plumb it (but, I've done that on a a few old BMW's & Volvos, no issues). How would you recommend checking the PVC system? Is there also an outlet somewhere below in the block with a filtered doo-hicky I need to check? (thinking back to the Volvos again...)

[Joe Johnston]

The old school way of checking a PCV was just to shake it and if it rattled it was considered OK. Possibly, but some valves are intended to be installed vertically and others horizontally as well as approximately sized for engine cid. When converting my 57 I used one for vertical instillation in a 302 which works well for me.

[sseebart]

Is there also an outlet somewhere below in the block with a filtered doo-hicky I need to check? (thinking back to the Volvos again...)

On mine at least, it's just a collection of hoses, fittings and tubing connected to the valve, nothing fancy.



~Steve

[greglilley]

wow, that's different. Mine just goes into the psngr. side valve cover into a nice tight rubber grommet, with the other end teeing off into a u-shaped metal tube that pretty much runs the length of the valve cover near the choke. both ends of this metal tube, if I recall, go back into the intake on top somewhere. Wish I could go check, but car's not here.
So it does not appear there is anything to check/clean down in the block itself, eh? Forgot to mention... '66 428.

[sseebart]

Yeah, '66 would be different as emissions regulations were evolving (not to mention separate rules for California). Mine is a 64 California car--sealed valve covers and all the PCV stuff at the back of the block. I would be surprised if there was more to service beyond the PCV valve on your car.

~Steve

[greglilley]

Geeze, totally forgot about this thread, very sorry. Looks like my "oil cap smoking concern" bit me in the behind, as it was accompanied by lots of oil leaking out onto valve cover and finally down under car onto exh. and smoking up the freeway (and eventually inside the cabin a bit, but at least it's not coming OUT the exhaust). Took 70 miles to get to that point of underside saturation. Posted a new thread/story of the mishap (Bird Bath) and would love to hear some thoughts from you guys, based on the current info. Thanks so much!