engine on and off smoking

[redsfury]

I've got an 85 ranger with the 2.3 efi,130000 miles, it had been sitting for about three years when I got it. I havnt run it much just down the road and back a couple times.it starts and runs beautifuly, but it will run clean for about a minute and then burn oil like you wouldn't believe for about a minute, and then burn oil again, hot or cold makes no differance. Checked the pcv valve, and put in a quart of marvel oil thinking it was a stuck ring, but it didn't make any differance. Theirs very little blow bye,no loss of power and it seems to run fine otherwise. Anything that needs doing, or can I just go ahead and drive it and hope for the best? Any odeas would be appreciated thanx

 

[stegomon]

Valve cover?

 

[Mark_88]

Well, oil can be introduced to the intake in two ways externally (so to speak) and you can test that to see if that is the cause.

As Stegoman mentioned, the VC is the first suspect as it is vented to the throttle body via a short hose. The second is the PCV valve. Both of these can be disconnected from the intake and you can plug the ends where they enter the intake to test.

you will need two caps to do this...and they can vary depending on the size of the hose used...even a short length of the same hose plugged with a bolt or something will do.

Once you remove the VC and PCV hoses and plug the openings, run the engine to see if you are getting the same result. If not, then that is your problem area. This usually means you do have a bit of blow-by and it is forcing oil up and out of the crankcase or VC and it ends up being drawn into the combustion chamber and burned.

If that does not resolve the issue then you either have leaky valve(s) seals or a problem with rings/head gaskets...or, worst case, a crack in the head near one of the valves stems that is allowing oil to get past the seals...

you could try adding one of those heavy "no smoke" goops to the engine to prolong the life until you can get it fixed properly...or engine restore...or whatever...

The engine has been sitting for a while and probably needs a bit of a break in...or it was wonky before it sat and you are just seeing the effects of neglect.

 

[70roadrunner]

also, if it is automatic, there may be a vaccum line to the trans. a bad accumulator will do the same thing. so will a bad power brake booster

 

[Mark_88]

^ true...although those two are less likely to draw in motor oil...

Meant to mention to pull the plugs and see if any are saturated in oil...that would indicate the problem cylinder(s)...

Also, does it smoke more at idle or when coming down from high revs? That indicates that it is more likely valve seals...

 

[RonD]

Yes you can drive it.
But this condition will ruin O2 sensor and the catalytic converter over time, so best to get it fixed

I assume "burning oil" means blue smoke out the exhaust pipe, not black smoke(to much fuel).
If it's black smoke then an injector is probably sticking open now and then.

If smoke is blue then pull off valve cover and look at the rubber valve guide seals, inside the valve springs.
These seals prevent oil in the valve cover area from being pulled into the intake by the vacuum present when engine is running.
These seals will dry out and crack when engine sits for long periods, three years is a long period .
Oil in the valve cover comes from cam bearings and is splashed around the area which is why "oil burning" might be inconsistent, on and off.

These seals can be changed without removing the head.