# Blue smoke, oil puddle. Valve stem gasket?



## KingJacobo (Jul 6, 2011)

After finally installing my Holley carb from hell my car is finally on the road again. However, a few days ago I noticed a decent sized puddle of oil under the car. The car has always leaked a little oil, but this was a puddle. Oil level was barely lower than before. Upon startup, what appeared to be whiteish-blueish smoke came out of the exhaust and it smelled like what I'm assuming is burnt oil, mostly out of the left pipe. 

After some quick research and a friends sight-unseen diagnosis, valve stem gaskets seem to be the most popular answer for my issue.

I had to drive the car 25 miles back to my college campus garage, and I was nervous about the drive, it ran perfect but you could still smell it 40 minutes of highway driving later.

Apparently valve stem replacement is majorly labor intensive because you have to practically pull the head(s)? I've never done engine work short of replacing the valve cover gaskets, if that even counts. I do however, have a good friend who has built/rebuilt a good bit of engines and may be willing to help if this is a serious engine issue.

Anything I should know? The car still appears to drive fine and i'll check in a few days to see if there is another puddle or just the previously typical drops of oil underneath. I just don't want to risk blowing the motor for negligence and cannot afford a replacement. 

Motor is 228k original well maintained miles, most likely not recently rebuilt, but runs perfect.

Classic car restoration/maintenance is hard on a college kid budget and with no nearby garage!


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## jetstang (Nov 5, 2008)

Valve seals will never leave a puddle, they are internal. External oil leak needs to be found and addressed. If it's smoking on one side, check and clean the plugs, note the oily one and keep on it. Replace it if needed and the smoke lessens. 228K miles on the old motors is a ton, they don't have the low tension rings. You are on borrowed time, treat her nice and hope it holds out untill you can get a rebuild.


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## Rukee (Feb 8, 2007)

:agree valve stem seals will/can cause a puff of smoke on start up, but not an oil puddle. With that many miles your guides are propably worn as well. Cheap a** generic oil can burn/leak more too.


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## geeteeohguy (Feb 2, 2008)

I agree with all of the above. Valve stem seals can be installed pretty easily "in car" if you keep the valves closed with compressed air or a bit of rope stuffed into the cylinder with the piston on TDC. But, with 228 k on the engine, a puff on start up is nothing to worry about. Top end lube! I'd find and fix the leak and just drive it. You could make 300k yet!!!


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## BearGFR (Aug 25, 2008)

Could be different problems, could be same problem... As others have said, valve stem seals aren't going to leave a puddle. External leaks can be tough because the oil will tend to cling to and follow surfaces until it reaches a low point, where it finally drips off. If you've got (for example) a leaky valve cover gasket on one side AND a poorly sealed exahaust manifold on that same side, oil can leak out and run down into the exhaust manifold, and also run down and cause a puddle. Then you get both a puddle and smoke on startup.

Here's a key question: once the engine warms up and is being driven, does it continue to smoke or does it "clean up"? If the smoke is coming from leaky valve guides and/or rings it's probably not going to stop with a warm, running engine. If you're just getting a puff of smoke at startup but then it mostly stops, then I'd tend to think what's going on is that hot oil is leaking into the exhaust system - probably at engine shutdown.

You've got to take sort of a Sherlock Holmes approach: Use logic to eliminate all the things that it either can't be or are very unlikely, then see what you're left with.

Bear


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## geeteeohguy (Feb 2, 2008)

All due respect, Bear, with leaky valve guides/seals, smoke generally happens on start-up. When the engine is shut down, oil has a chance to flow down the valve stem and into the cylinders. Also, on heavy or extended deceleration where a high manifold vaccuum is pulled. If it is smoking at all times it is runniing, it is more probably piston rings/cylinders that are worn.....JMHO


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## BearGFR (Aug 25, 2008)

Reckon? You know... thinking about it, I can see where cylinder pressure would tend to keep oil from running down the valve stems in a running engine on the exhaust valves. If it's the intakes though, seems like it could actually be worse on a running engine if the guides were shot, wouldn't it? 

One way to find out if it's rings or valves is to run an old-style compression test. Measure cranking pressure on each cylinder (dry, all the plugs removed, throttle blocked open), then measure each cylinder a second time but squirt a few shots of oil into the spark plug hole aimed at the "top" of the cylinder right before measuring that cylinder. If pressure 'improves' quite a bit, then you know the rings are leaking. If it doesn't (and that cylinder is still significantly lower than the others0 then pressure is leaking past the valves/valve guides.

Bear


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## Rukee (Feb 8, 2007)

That doesn't always tell either, I had smoke while running and the compression test showed at least 175 on every cyl. Pulled it apart anyway and the one piston was broke just below the top ring land. They guy before me put in cast pistons and with the combination of 10.5:1 compression and the wrong distributer swinging the timing the wrong direction, it was a recipe for disaster.
I still have that piston on the rod for a reminder...... so I always keep in mind when working with anything mechanical, anything is possable. I even seen a car come in (and drive off) with a broken crankshaft and when I told them it was broke and that was causeing the oil leak they accused me of trying to rip them off... :lol:


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## geeteeohguy (Feb 2, 2008)

Bear, as always, your theories are logical and make excellent sense. I discussed with a colleague the possiblility of a valve cover leaking oil into a cracked/loose/blown-out-gasket exhaust manifold, and therefore producing the puddle _and_ the smoke. I have 33 years in the industry as a pro, he has about 37 year in. Neither one of us has ever seen it happen on any car. Ever. Not to say that it couldn't, because it certainly could! We've just never run across it. As Ruk says, never say never!! I'd clean the heck out of the underside and topside of the engine, and locate the leak and go from there. At 228k, I would look the other way if I saw blowby or some blue smoke out the tailpipe.....again, just my humble opinion.....I had a 428 once with 4 broken pistons and it too had ok compression, but had leakdown issues. Cast pistons that had the ring lands broken out of them. Never heard a thing!!


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## BearGFR (Aug 25, 2008)

Yeah, I can see where broken ring lands wouldn't seal no matter how much oil you put into the cylinders, so the oil compression test isn't a guarantee either. Truth of the matter is, the only way to know for sure is to tear it down and look. Until you do that, you're just really dealing with probabilities.

Bear


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## geeteeohguy (Feb 2, 2008)

Yep. And you hit the nail on the head with your valve stem sealing theory....a lot of guys don't run seals on the exhaust valves at all....just the intakes. We've all seen a lot of WEIRD stuff with mechanical items over the years, and until verified, virtually anything could be an issue......


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## jetstang (Nov 5, 2008)

Rukee said:


> . I even seen a car come in (and drive off) with a broken crankshaft and when I told them it was broke and that was causeing the oil leak they accused me of trying to rip them off... :lol:


OK, want to hear the story on this one.. what wasn't spinning, front or back, assume the front.


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## jetstang (Nov 5, 2008)

geeteeohguy said:


> Yep. And you hit the nail on the head with your valve stem sealing theory....a lot of guys don't run seals on the exhaust valves at all....just the intakes. We've all seen a lot of WEIRD stuff with mechanical items over the years, and until verified, virtually anything could be an issue......


Makes sense, exhuast valves are pumping pressure out, while intakes are sucking. Good stuff.


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## Rukee (Feb 8, 2007)

jetstang said:


> OK, want to hear the story on this one.. what wasn't spinning, front or back, assume the front.


They came in wanting a front main seal which was leaking. I grabbed onto the front pulley and was able to move it a couple inches! Just by the way it moved you could tell it was broke just after the first main bearing. I asked how long it had been leaking and they said a couple weeks, but just started leaking bad after they went to Milwaukee and back last weekend.When I told them the crank was broke they called BS saying they use to turn cranks for Dealers manufacturing. So I was like yeah> So when you turn a crank you have to keep it within what? 0.002"? And they were like yea, that sounds right. So I grabbed the pulley and moved it the couple inches and asked Does that look like 0.002" to you? That's when they said I was trying to rip them off and drive away. :lol:


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## KingJacobo (Jul 6, 2011)

Great ideas here! I've driven twice since I noticed that puddle and there has since been NO significant oil leaks. (?) Been busy with school and haven't had a chance to really look under the car (no jacks/jack stands either) and the burning oil has also mysteriously gone away. 

Very strange, but until I really get down and under I'm not sure what I'm dealing with.


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