froggy47

I am chasing a oil leak, I thought it was front crank seal, then front engine cover gasket, then oil pan.

I put dye in & got to looking again today & (after weekend event) they dye is all over.

So it only happens at high rpm events, daily driving does not make it leak.

My question, is there PRESSURE at the oil drain plug? If yes, how much?

I did have an oil leak at the oil filter one time (one of those new eco friendly filters - which IMO are crap) and I put a WIX on and it sealed up fine.

I am thinking if there is pressure at the oil plug under high rpm maybe I should try a new plug before I tear the front of the engine off. There is a big drop right on it. It is torqued to spec, but is original.

But I really don't know the system, if it's atmospheric pressure only/gravity or does some pressure build up in there when I redline it. I was at an event (autox) that necessitated riding the rev limiter for quite a few secs yesterday & if there is pressure build up that would have done it.

Thanks if you know anything about this semi dry sump system.

RX-Ben

Is this for a C6Z or a C5Z? C5Z is wet sump.
Where is the leak (i.e. where is "all over")?

froggy47

Most call the LS6 a semi dry sump, but, not to dwell on that.

The dye is on both sides of the spring and back to the pan bottom.

I really just want to know specifically does the crank case area pressurize under high sustained rpm 2-3 sec on rev limiter? If so how much?

The dye spread too far to make a diagnosis of the leak source except that it is dry around the crank seal.

No leak at all under "normal" street driving. 300 miles.
Thanks.

Bill Dearborn

Took three trips to my dealer to find the oil leak on my LS7. It only showed up when revs were above 5500. You say you have covered the front cover seal which is where mine was leaking. Some people reported they had similar high rpm leaks where the main bearing cross bolts go into the block so you may want to check them.

Bill

RX-Ben

The main crossbolts are tty, so you need to replace them and they should have sealer applied to them when installed.

Do you run a catch can setup? Pressure can develop at higher rpms.

mountainbiker2

Check your air cleaner and throttle body. I use to get oil all over the place, before I put in two catch cans. Also your oil fill cap.

Steve A.

froggy47

If I put a can, how does that REDUCE pressure? I know it reduces the OIL that goes thru the TB, but the TB air flow would (I think) aid in the reduction of pressure by sucking the pressure from the crankcase, or is that all wrong?

froggy47

Air cleaner (K&N) is good & checked each event.

What is to be checked on oil fill cap? It's there.

TB has mild oiling as you would expect from a car that does not have a can (yet).

There is no trace of oil/dye from above that I can diagnois.

I am just wondering if at high pressure the oil change bolt rubber o ring is pizzing a tiny stream of oil that gets swirled all over at speed. It's a pretty flimsy little bit of rubber o ring.

RaleighSS

Look at photos 54 through 60 I had an oil leak as well and it was my front main seal ...I pulled it down put a pump and timing chain in at same time ...

http://s41.photobucket.com/albums/e2...DSC_0017-1.jpg

froggy47

Well thanks, that is all the same area that I am getting oil, but my front main crank seal is dry as a bone.

Bill Dearborn

You may want to take another look at the front cover gasket. When I was running the engine at high rpms the leak from the front cover gasket threw oil as far forward as the front stabilizer bar, all over the front spring, down both both sides of the engine with more oil on the driver's side, it was all over the C6Z oil cooler line, the oil filter, the bottom of the car and the driver's side tires. Around town the oil filter and the oil pan got covered with some oil. It took three trips to the dealer to get the leak stopped. First, they replaced the stock oil cooler line, then the pan gasket, and finally the front cover gasket.

Bill

froggy47

I think I will clean it again and try running it hard 1 or 2 times & then look.

Rob's 73

Try venting the crankcase with a breather.

froggy47

Is this the same as an oil catch can? My dad's 1950 Dodge had a crankcase breather as I recall.

Where does it go?

Pic?

crainholio

The vacuum port connected to your PCV has no vacuum on it at wide open throttle. If your PCV is factory configuration and working properly, eg. not blocked or hose kinked, it should allow crankcase pressure in excess of 100KPA (or whatever your ambient atmospheric pressure is) to vent passively into the intake.

I've seen LS1 cars have problems at WOT when somebody has replaced the PCV valve with an aftermarket check-ball type, problem is solved when a GM fixed orifice PCV valve is installed.

The LS6 has the PCV integrated into the lifter gallery cover and there's no separate PCV valve that I can recall...check your line from the intake to the lifter gallery connector to ensure it flows freely.

froggy47

It's all stock, is there a way to check without pulling the intake?

Somehow or other at HIGH RPM there is too much pressure. Engine runs great & does NOT use excessive oil. It's all very stock & I run it hard.

CP Thunder

There is an unused (normally) oil galley plug on the lower front left side of the block under the alternator and a few inches beneath the water temp sensor.........make sure thats not your problem.

froggy47

Ck, it's bone dry