what would cause this... I have yet to get under there and check the problem b.c i havent had time at all to do it.

I jumped in the truck to go to work this morning and the dash dinged at me and said **Check Oil Level**, I was like: Oh S***.

I popped the hood, checked the levels. Added a quart and a 1/2 and the levels where fine. I saw the vacumme hose on the valve cover was off, so I plugged it back in. My oil pressure gauge was up to around 80. I pulled onto the interstate and heard a loud pop and hiss from under my hood. Slowing down, I noticed my oil pressure had dropped to normal (around 40). I popped the hood and the vacumme hose I plugged in had been blown off. So I just left it alone.

My guess is the oil leak is coming from my oil pan gasket???

I have a Whipple supercharger, and I haven't raced the truck in about 2-3 months. And when I was racing about twice a month the engine was perfect.

Anyone have any ideas? is it safe to run my truck as it is? Should I be worried?

Thnx.

**edit

BTW, my truck specs are as follows:
-2003 5.3L Z71
-just hit 25,000 miles
-Whipple Supercharger with 12 lbs pulley
-CompCam Camshaft
-Upgraded transmission to handle more power.
-4.10 gears
-Alky Injection kit
-Electronic Cut-outs
-Custom Computer Tune.
-410-whp 438-tq.

 

In any engine pressure builds in the crankcase and is relieved through the valve cover breather or hose to the intake. This pressure is even greater with a boosted engine. If the breather is blocked, pressure builds until it can force its way out the weakest point. This is usually the front seal behind the pulley/balancer and partly the rear seal. I've seen the oil dipstick blow out and spew oil. The oilpan gasket, valve covers, and intake usually hold but may also leak. When boost is increased over the original design, (I see you're at 12lbs) there is even more pressure and that may require a bigger openning, hose, pcv, or a catchcan. First thing to do is check the top of the engine and find for the obstruction in the breather.
Or you can just let it continue to leak and keep adding oil. After you remove the blockage it wil probably still leak a little from the front seal if it's not replaced.

 

having cleaned the bottom of my motor and changing the oil, I found that the oil leak was coming from the PCV valve conncetion.

I checked the pcv valve and found out that it was letting air back the other way. And running a boosted motor, I figured this was the problem.

I ran to autozone and bought a replacement PCV valve and put it on. I wasnt even out of the residential area, and the valve blows off (waaay earilier than the old PCV valve I replaced).

There is a lot of blow back coming from the top of the valve cover.

Anyone have any idea on what the problem could be? The motor sounds perfect, and runs clean and strong, although I do feel a slight loss of power than before.

 

bad rings ???....or, although not likely as you'd REALLY notice it, you could have popped a hole in a piston.....

 

OK... After more testing, the PCV valve only blows off when under a load. (ie: engine in gear).

I tested this by putting the truck in gear, then reving up the stall converter. And pop, it shoots off the valve cover. Even at low idle speeds it does it also (in gear), it just takes longer b.c it has to build up pressure.

So my guess is that there is something wrong with the transmission. Its like its not sucking any air, and all the pressure (which was meant for the tranny) is being pushed through the vacumme lines.

Any more thoughts?

(Yelo) I highly doubt I put a hole through the pistol, you would think smoke would be coming out the exhaust pipes no?

 

Sounds like REALLY BAD blow-by to me, the only things that can cause THAT kind of a leak are:

* Bad Rings
* Bad Valve Seals/Guides
* A Hole in a Piston

I don't think the trans has anything to do with it at all....the only way a PCV valve will shoot out of an engine is the crankcase being pressurized by blow-by

And, no....a small hole in a piston won't necessarily smoke at all......I ran around with a popped piston in an old Chevelle I had for over 3 months 'till I finally got around to swapping motors on it....and it never smoked or used oil

Get a compression check done on it ASAP......

 

I believe I have heard of this before. Not being intamately familiar with the whipple system it is hard to diagnose but if the pcv valve isn't moved to the suction of the whipple then you will be pressurizing the crankcase when under boost and causing the pcv valve to pop off. Also the factory pcv's have a small orfice hole and the aftermarkets have a large hole with check valve. That may be why the replacement blew off faster.

 

The PCV valve has a blow-by stop built inside of it. When the whipple boosts, it sends compressed air through that hose to the PCV valve, the stop slams the hose shut and thus seals off the intake. BUT, the PCV valve is getting blown off from the opposite way! The compressed air coming from the valve covers has enough pressure to blow off the PCV valve even under idle.

If it was a pistol ring, would I be hearing all sorts of noises? The engine sounds perfect, I don't know how many times I can say that.

THE ENGINE SOUNDS PERFECTLY FINE

Can someone explain to my why the PCV only blows off when the truck is in gear?

Also, a compression check is related to the cylinders yes? How would this effect the INCREASED pressure in the vacumme lines?

 

If it is blowing it out at idle then you most likely have a broken ring land on the piston, if not a hole. This is usually caused from detonation. busted rings or ring lands won't always make noise. I have had them that did and didn't.
When you are in gear and idleing more load is put on the engine causing more cyl pressure. I hate to say it but you most likely have a bad engine failure. A compression test should tell you the truth. I did have an engine that broke the ring land between the 1st and 2nd ring and showed fine on the compression test but would soak the windshield down with oil due to blow by at WOT. You will most likely be able to find your bad cyl by comparing all the spart plugs when you pull them. Good luck.

 

Dude...it DOESN'T MATTER IF THE ENGINE SOUNDS PERFECTLY FINE !!!!!.....get a compression check done !!

The small loss in power you mentioned earlier can 100% be attributed to blow-by past the rings (or a holed piston)...being that you've got a blower on the motor you won't notice the power loss as bad as you would N/A