To diagnose blowby, what tests are done? I will ask how they diagnosed blowby.

 

go to a independent shop and have them do a pressure test on the intake manifold and on the cylinders, that should answer all your questions once and for all.

If there is oil in the intake then it is a plenum leak. If the repair was done with rtv and a stock gasket it won't last that long. If they used a steel gasket it would last a little longer, and from what I hear and belive a plenum kit will last the life of the manifold. I am in your area, if you want me to look at it and give you my $.02, it would be no problem.

If there is blowby, the pistons with the worn rings would have a lower pressure.

 

They would have had to done a leak-down test on the motor, to determine if there is an excessive amount of blow-by

 

Thanks all. Let me think about this and get back to you. Nolazach: I will give it some thought. I appreciate the offer.

Jeff

 

OE812,

Besides the pooling in the intake... you can do a simple vacuum test...it will help the diagnosis...its described here in the forums... its easy to do your self...

Blow by isnt going to puddle oil in the intake....and.. if your plenum's blown.. the vacuum test will let you know almost for certain. Disconnect the PCV hose from the intake, plug them both.. the hose end and the port you just took it off of on the intake... then pull the hose off your air box, ( airfilter box, ailcleaner...whatever your used to calling it..) it connects at the bottom I think on yours.. that hose runs to your other valve cover...after disconnecting the hose from the air box.. start the truck... see if your getting any vacuum through that hose...you shouldnt be...or at least very little... when my gasket was blown.. ( still is... havent changed it out for my Hughes yet..) it had alot of vacuum.. a significant amout.. see, when you pluged up the PCV hose and intake port.. you basically should have cut off the circulating air... so there shouldnt be any Vacuum through the other hose comeing back to the air breather....if there IS a strong vacuum.. your plenum is most likely leaking....your intake is sucking air through the blown plenum gasket.. basically a huge vacuum leak. As I've learned here in the forums.. this can cause a host of problems.. rough Idle, power loss, poor shifting, loss of oil even though you dont have leaks...etc..its not bad to fix yourself, and the APS and Hughes kits are good upgrades to the stock pan. Good luck...

 

Explain this please. The mechanic said thepiston rings are worn causing blow by. Wouldn't a previously busted intake gasket cause dirt/debris to wear the rings at the piston head coupled with the pinging?

 

Picked up truck and will have work done by indy mechanic once my extended warranty kicks in mid March. The dealerships can blow me.