Oil blow by not blow by?
 

New to this forum and I am hoping you guys can help me out. Here is the situation: 92 Caprice, two engines now are blowing oil out of the dipstick tube. Thought the rings were bad in first engine so I swapped a known good engine into the car and get the same problem. The only items swapped over were valve covers, oil pan, and throttle body. Second engine had no issues with pressure or blow by prior to being installed in this car. I swapped out the throttle bodies with one from another 92 parts car I have and the problem went away for a short while. Only seems to blow oil when I really get into it. If I baby it oil will still barely spit out. I have replaced the PCV twice and the tubes as well and still has the same issue. I know a lot of you will say that it's the rings getting bad, but this second engine had no issues at all in it's prior home and only sat for a week while the swap was being done.

I'd say PCV, buy you said you checked/changed all of it so.... Check it again, if you're sure the engine is in good mechanical condition. Are there any other oil leaks? Is there any oil in the air filter housing where the PCV tube attaches?

No oil leaks anywhere else, and no oil in the air filter housing. I am going to swap out the valve covers and breather system for the one from the truck and see if anything changes. If not it's back to the drawing board.

Where is the PVC valve placed / installed ? Is it plugged into a rubber grommet in the valve cover ?


Is the engine blowing oil at idle or while driving or both ?


God bless
Wyr

Only blows oil under acceleration. PCV is on drivers side valve cover in a grommet. I took the valve covers off and had a local shop hot tank them for me, the baffles were full of build up. Can't believe I didn't look at them before I swapped them over. I reinstalled them and it seems that for now the oil blowing has gone away for now. This happened after I replaced the t.b. as well though and the issue came back after a couple weeks.

Hope you have it under control . Best of luck to you . :-)

God bless
Wyr

I hope so too.. I confused 4 mechanics including one at a dealership with this one. Oil pressure was always good, compression I was told was in spec so it was kind of odd. Now on to my heat issue...oh joy.

An update on the blow by. It's solved. I have not had one lick of trouble with oil coming out of the dipstick in the last two months. Here's a lesson, don't believe it when everyone tells you it's bad rings until you have cleaned everything.