first off some back ground myself and the truck. I am fairly new to tuning gas with efi live. I have pretty much tuned my truck my self with TONS of help from some great guys particularly Gadgetized. Fantastic guy cant thank him enough.

Specs on the truck are some basic motor work and P1sc running around 10-11psi max. Oh I do have my Valve covers vented into a RX catch can with the RX breather cap.


So recently I completely had some dyno time to just fine tune the truck. after I was done I noticed some oil under the truck, it was all over the bell housing and sway bar. I could not see were it was coming from but looked like the oil pan was leaking. So I cleaned everything up and retrqd the pan. Boom, everything looked great no more oil.

Then the other day I was working on dialing in my fueling at WOT( I am still learning EFI live,lol) when I pulled into the drive way I saw it again. drip drip drip. now its just the rear of the pan. Looks like the rear main is leaking. I cleaned it all up and drove normal and there is no oil leak, so assuming it is only leaking at high boost. I spoke to a few people that are boosted and I get the same response "mine does that too, drives me nuts" LOL. So assuming the rear main seal does not necessary leak but it weeps at high internal pressure.

I do not see the need to pull the trans for a seal that is going to weep again at WOT but what do you guys think?
has any of you ran into this problem?
is the cause due to high manifold pressure? my oil pressure hits about 50 at WOT and I am running RP 5w30 with full syn Lucas oil additive.


I apologize for the long post but hope to resolve this not only for myself but for others, thanks.

 

That sux. Plenty of people on here pushing way more than that without any problems including myself @ 12lbs. I have a one way check valve on the driver valve cover to the intake and the passenger vented pre turbo and havent had any problems yet.

 

I am running more boost then that and haven't seen that, my oil pressure also runs above 75 at WO. That's not normal. Exactly what does your breather system consist of?

 

I have the driver side valve cover ran into the passenger side one then I have the RX breather oil filter cap that runs into the rx catch can that is vented to atmosphere. I am thinking I can not run the two sides together.

 

Ok, so i think i figured it out. I have the RX oil cap breather and I had put some cotton ***** in there to help "filter" the air coming out but I realized that it causing back pressure and lots of it. not allowing the the valve covers to vent properly. So hopefully that will fix it.

 

I run a one way check valve on the drivers side that connects to the Downpipe(Mr gasket kit but , used a modified check valve to fit the valve cover) And on the passenger side I have the oil filler cap going to the catch can just like you. I've tried a few styles and this works the best. I've replaced the rear main seal a few times and wasn't doing it a third. I run 20+psi. Also what's the deal with oil pressure? That seems pretty low

 

what should oil pressure be at WOT? could you send me some pics of your setup? sounds legit.

 

your oil pressure is normal for the 800 motors, the 900 motors have a bypass in the oil pan. Its for the motors that were VVT so they regulate oil pressure lower

My truck has been this was since new which was 75k miles ago



now to the OP, if you dont vent the motor properly you will blow the rear seal over and over again. had this recently happen when my vent lines froze up from condensation and it pushed oil out the rear seal.

make sure you run the two valve covers and the valley cover to its own catch can that is vented and youll be fine. you can not put pressure into the crankcase or youll blow the seals everytime you got into boost


i also have a 5.3 with a p1sc with 11-12 psi and on no timing made 540/554 with heads and cam setup

 

I don't know if you have figured your problem out yet, but at the dealer I work at we replace a ton of the oil pressure sensor's at the rear of the engine, they usually have two issues, either an oil leak that runs down the back side of the engine or, erroneous oil pressure readings, or a combo of both. Hope this helps