So I noticed yesterday that I have smoke coming out of my oil cap and dipstick tube if I open them.

I can not tell if the smoke is white or blue due to a color deficiency that I have.

I noticed yesterday that after making a WOT run it got significantly worse for about a minute (you could see smoke rising from under the hood and a burning oil smell) and it also looks like it may have shot oil out of the dipstick tube which may be the cause of it getting worse for the minute or so.

It does not do this when the engine is cold, at least not that I have noticed.

The car has been running a tiny bit rougher since this started and I am not sure what to do at this moment in time.

The car is a 1989 with just under 100k on the engine and has never had any major work done to it.

Here is a quick video of the car at idle where hopefully others can see the smoke coming from the oil fill cap.



I am not sure if this is caused by bad piston rings or maybe bad valve seals, but I would Like to fix this problem soon before it gets any worse.

If you need anymore info please let me know.

Thanks, Stephen

 

This is called blowby. Combustion gasses are passing by the piston rings into the crankase. Your engine needs a rebuild.

 

I figured that is what was gonna need to be done. And thanks for the response.

So first off, since if I am gonna have to rebuild the engine, I might as well start gathering parts for the 383 or 396 that I have wanted for a while now.

Is this blowby something that will kill the block if I continue to drive it lightly like I normally do or is it something that can wait? Cause I'd rather drive it til it wont drive anymore, as that will give me time to save up the money and buy parts as time goes on. But at the same time I don't want to crack the block and add more expenses.

Also I might need a parts list and a good "hook-up" for someone that can do porting of the heads and engine machining for a good price. I live in the panhandle of Florida if that helps at all.

Looking for something that can stand daily driving abuse and be a weekend track car if I ever have that urge.

Thanks, Stephen

 

Check your PCV valve. Its purpose is to suck the oil vapors out of the crankcase and feed them into the intake manifold so they get burned instead of polluting the atmosphere.

 

It has a new pcv valve and grommet about 6 months ago or more. I checked the valve this morning and I could hear it rattle with the engine off and with the engine on it had suction and the valve did not rattle.

I am currently at school but when I get home I will pull off the hose and check to see if it is clean which I am pretty sure it is due to the strong vacuum.

Is there other items in the pcv system that I do not know about and should check?

 

I would look over the entire PVC system, hoses, valve and all AGAIN !

This engine is far too young to be in need of rebuild unless its been horribly abused !

100K ain;t ****. It should do twice that and still use less than 1 qt in 2000 miles.
I suspect the PVC system is AFU or....it HAS been very abused, run over heated for an extended period of time, or gone too far between oil changes. Abused.

Are you using oil? how much how often?

All these things CAN come from a single cylinder that's got broken rings or even a holed piston. You say it runs rough...MY next test would be a compression test on each cyl.

 

So how would you recommend me fully testing the engine pcv system?

Also I got the car at just over 80,000 miles and it was a barn find with hardly any service records. So I have no idea how the car was driven before me.

How would I go about doing a compression test on the engine?

Thanks for all the help. Hopefully it will be something stupid but if not then oh well.

Thanks, Stephen

 

you need a engine compression gauge hooked to each cylinder plug hole rotate the cranck pulley and see what the gauge indicates,repeat for each cylinder and report down the result in PSI.

 

Yup.
Its a PITA screwing the gauge hose into each cyl spark plug hole, but....that's what ya godda do. Follow instruction in compression test kit. Always have throttle WFO to get accurate reading and cycle the crank 2-3 full revolutions. It cannot bump it up more than its normal compression due to some being lost at each 'cycle' thru the ex valve. IIRC you will need to see about 160 psi to be healthy, 100 psi is the absolute min that a cyl can have and be useful. IMO anything under 130 needs to be repaired.

PCV....that's gonna be mostly visual inspection and making sure the hoses and lines are not plugged or damaged, cracked or open.

PCV means Positive Crankcase Ventilation.....where the engine intake is using its vacuum/low pressure to evacuate the fumes from the case. If there is good tight rings there are not 'wet' fumes or smoke. If there is combustion gases getting into the crankcase, that will get sucked out to be reburned and that will also tend to foul plugs and cause hard starts, rough running. PCV should hold a vac on the crankcase since there is no way for any gases to enter...if its in good shape.


Smoke "puffing" from the pvc hole or dipstick can only come from burning gases that are supposed to be on TOP of the piston. the ONLY way they can get below the piston is thru weak/broken rings, a hole in a piston, or a huge scar in a cyl wall. Maybe some really really screwed up valve guides and seals.

the compression test will show 1 or more cyl that's not sealing and THAT is where you find your source of the trouble.

 

I rechecked the PCV system and all looks good. Good vacuum and clean hoses.

The smoke is coming out of the oil fill cap and the dipstick tube.

I am gonna try to go and get a compression tester tomorrow and test the cylinders and see the results and we can go from there.

At the same time that I hope it is nothing serious, I do kind of want a reason to build a 383 or 396

Thanks for the help so far.

 

Best way to check is by running a leakdown test. This will show you how much leakage there is in each cylinder. The amount of smoke this motor is putting out isn't going to be sealed by any type of PCV system. A healthy engine should show very little if any blowby without a pcv valve. I don't run one at all on my motor and there is no visible blowby. My leakdown numbers are 2-3%.

 

Yep.
A tight engine wil not 'pass' exhaust gases into the crankcase. The PCV system is there to maintain a vac against that case to eliminate ANY that MIGHT APPEAR. A good tight engine doesn't need a PCV but the feds cannot be sure of who has a good eng and who does not, so everybody gets a pcv system to be sure...
its really just a very simply means of preventing tired engines from puffing smoke as the load on the engine increases.

 

I went out to a friends shop and he lent me his leak down tester and compression gauge. He told me how to use it and a neat trick to find TDC using it.

I plan on doing it tomorrow or Sunday and writing down all the numbers and posting them here along with any air noises and where they are coming from.