oil coming from dipstick tube

I test drove a car today, driving it roughly 2 or 3 miles. got back to where the car was parked and stopped the engine. I lifted the hood and it seemed really hot. I pulled the dipstick tube out to look at the oil and there was smoke coming out of the tube. Is this something to worry about? It was a 4.3 v6 if that matters.

 

What do you have for crankcase ventelation? Pcv on one valve cover and breather on the other? I'd want to think that blowing oil out the dipstick tube means that there is way too much pressure building up in the crankcase because it isn't getting ventilated properly.

 

It is a stock motor with 82k miles in a '91 S10

 

Could be a plugged PCV system or too much blow-by. Did you try running it with the oil cap off? A 4.3L could be toast at that mileage if it wasn't taken care of.

 

did it run hot? blown head gasket? color/smell of oil? did you buy it, or just looking?

 

I've had water coming out the dipstick tube but thats a whole nuther story.

 

If it had ever had the poppet injectors go bad (Stick open) it can wipe out rings in no time at all. Did it run rough(er) than usual? Cheap oil or old oil can quickly vapourize and a little smoke coming out of the valve cover ISN'T normal; but seems to be with the 4.3. Head gasket leakage on those engines usually stems from a broken head bolt(s) @ #5 or #6 and a white plug. Done TONS of 4.3 head gaskets, but don't recall seeing external leakage, just a/f consumption. As a side note, when those engines have been ridden hard, that particular mileage is about when they start to smoke , run rough or knock a bit from the mains- especially if an injector or 3 has barfed in the past and the previous owner waited for a while before lifting the intake plenum and throwing money under it in order to keep it running.

 

Could excessive crankcase pressure cause the rear main seal to leak oil?

 

Some of the 4.3 were known to leak coolant into the lifter valley via leaking intake manifold gaskets. Well known and documented problem.
If the coolant system never holds pressure its a sure sign of this problem.
White smoke out the exhaust and anti freeze smell out the exhaust is another sign.

 

so, unless you are getting to for $100 or less pass on by the oil blow by

 

When you shut the engine off, the PCV valve is no longer working. There is no vacuum to suck out the fumes. If it's just a wisp of oil vapor I wouldn't get all up set.

If it's puffing out oil fumes when running then you need to check the PCV system and probably do a leak down test to see if anything is seriously wrong.

 

Yes, a neighbor put a chevy/Mopar nonvented oil cap on his Ford & blew out the rear main seal.

 

Uh let's see.... Now we're discussing "traditional" S-10's????????

Sorry guys but there's something just not quite right here.

 

huh! I thought this was a forum about old cars.

 

I have a 48 Studebaker with the original/rebuilt flat six (it was rebuilt a long time ago but never run that much). I replaced the head with a polished finned aluminum head, cleaned all the valves and the top of the block, new head gasket etc. Two problems: It has been two years since I fired the motor (after restoring the rest of the car). I now have a white-ish smoke coming from the dip stick tube and oil now leaking from the rear main at a slow pace. I really don't want to pull this motor again and am hoping I can relieve the crankcase pressure (if that's why the rear main is leaking now) by checking the road breather and oil passages by the valve springs on the side. What else can I do before pulling the motor? Is it possible the motor needs to be run and the rings just need to expand to seal up? Ungh...

 

it's a 91'. 20 years old. classic man, classic..........
seriously though. i think he just wanted to pick people's minds on this forum, because there is alot of knowledge here. -DVZ