CHRRRIS

Well I had a highly recommended shop look my motor over and try to pin point an annoying leak on my 98Z last summer. They did the front main seal. Still leaked. They looked it over again, cleaned it up, ran it... They did a weird seal that sits vertically near the oil pan and bellhousing, rear main at same time, and oil pressure sensor up top.

Still leaked... ONLY from one spot. The little cover over the oil filter. I got a new cover and gasket myself and replaced it.

Still leaked... The leak is definitely coming from right about that cover through the oil pan gasket. It is the only place leaking, and it only leaks a few drops after every good drive.

Now my PCV set-up is deleted. (Car is bolt-ons...LTs, True Duals, LS6 intake, P&P TB, free mods) I have everything capped off with a breather on the oil fill neck. Is it possible that my breather is clogged, or somehow my crankcase pressure is too high that it is always forcing oil out of the weakest link? There is some oil on the inside of the breather neck, but not a ton...

I've been doing a ton of research and it seems like nobody else with this PCV set-up has this problem, except I did see this...

What should I try to see if my PCV system / Crankcase pressure is the culprit of my leaks? Add a small breather to the driver side valve cover?

I don't really want to go to a stock PCV set-up, I'd rather go to a LS6 valley cover for the money... but trying to identify the problem before throwing even more $$$ at it.

sjsingle1

iTrader: (1)

was the rear seal replaced? if so.............was it put in the right direction? if not it will leak.........and you can install a LS6 cover with no worries

CHRRRIS

Rear main was replaced. the only leak left is definitely coming from the oil pan, but I'm pretty positive it was never leaking there before the other seals were replaced... that's why I suspect my crankcase pressure may be really high..

sjsingle1

iTrader: (1)

i thought a breather in place of the oil cap was just a vacum leak?????

CHRRRIS

With everything else capped, it is simply a vent for the crankcase and this way doesn't let any oil whatsoever into the intake manifold.

Car is still leaking oil, anybody got any ideas?

mrnorm_hemicide

iTrader: (17)

I wouldn't suspect the breather. That size breather is more than enough crankcase ventilation for a stock motor. I would try cleaning the filter if you haven't already. Oil vapor will become trapped in the filter and over time will clog it like any other filtration system.

Mumbles

iTrader: (5)

It seems like you've been very proactive trying to solve this problem. That's good, but makes it even more of a "head-scratcher", when you don't see any results.

I've seen threads on here where an oil leak turned out to be a small crack in the Oil Pan.

I'm not saying that's definitely your problem, but I guess its a direction to look into.

Wish I could be of more help. Good luck, man.

jimmyblue

iTrader: (11)

That "little cover over the oil filter" - is that the oil
cooler port, blocked off? Maybe needs a new gasket?

PCV should maintain a slight negative pressure in the
crankcase, but can only do that against relatively low
blowby gas flows. The cooler port, however, is not
crankcase - it's pressurized.

CHRRRIS

Yes it is the oil cooler port. After having the seals replaced I was sure it was that that was still leaking, so I bought a new cover and gasket from GM and replaced it, but when I looked at the area from above with the engine running, it is pretty clear that oil is leaking through the pan gasket just above the oil cooler port.

It may just be the oil pan gasket that needs to be replaced, but I fear it will just cause a different seal to blow out again if my crankcase pressure is too high. But are you saying the crankcase can not produce so much pressure as to blow out a seal, even though I have everything capped with a breather? I am not running stock PCV in case you were confused, so idk if I have negative pressure.

Alex - I'll try cleaning out the filter and see if it helps.

mrnorm_hemicide

iTrader: (17)

Crankcase pressures can become high enough to ruin seals. If you were running no pcv system whatsoever, the pressure would build up to the point where it would be forced to exit somewhere: gasket, seal. I would venture a guess that you either have a pan gasket that has deteriorated to the point where it has sprung a leak, or worst case scenario you have a small crack in the lip of the pan.

blkbird

iTrader: (28)

Heres one for you. I was also chasing down a leak for months. I replaced every seal possible in the block and what i finally found that solved my problem was that the o-ring on the dipstick tube was blown and was causing oil to come out during high rpm's. Give that a shot. Once I replaced it, problem solved!!!

Viper

iTrader: (6)

Good call on the oil dipstick o-ring. That was me 5 years ago, high rpm was blowing it out of the block.

CHRRRIS

Ok guys little update. Car's still leaking, it may be the oil pan, but it may not be. Today my low coolant light went on so I checked the reservoir and it was very very low. I filled it to where it should be, but now that I think about it...

I may be leaking coolant. The fluid on my garage floor is pretty clear, but almost like a clear-brownish. Almost like fresh oil, even though I changed my oil 1500 miles ago so I would think it would be darker by now. The fluid has no distinct smell, however I can't smell anything distinct from coolant either.

Is there anywhere coolant could be leaking that would drip down the oil filter, onto the bottom of the pan? Because it's right under there that the fluid builds up on my floor... I'm lost!

Also my power steering fluid was low, hell maybe that is leaking somewhere, I don't know! This sucks...

OUTLAWZ RACING

iTrader: (9)

The coolant tubes that run on the back of the heads may be leaking. Have u tried the knock sensor gaskets they are located in the valley cover.

oh and the water pump will weep befor it makes any noise.

ChucksZ06

iTrader: (9)

The oil pan gasket can leak in the area directly above the filter cause pressured oil runs thru that area. I have one that is leaking a little bit exactlly like yours.

CHRRRIS

No haven't checked any of that. I will try to make time tomorrow. I've been doing a ton of research into coolant leaks and it seems like there's many many places that could leak coolant. I may have to do a pressure test? I'll try to see if there's any liquid by the water pump.

I just don't understand how a very well known and trusted shop could not have checked any of that the multiple times I've had my car there.

Are you sure it's leaking through the gasket? Do you have an LS1? Is so, what kind of PCV set-up?

CHRRRIS

Ok the water pump appears fine. So does the power steering. I guess it could be a coolant line behind the heads (if not the pan gasket), but how can I check for that? It is impossible to see back there.

Oh it's not the oil dipstick either, no oil around it. Leak is coming from directly above oil filter. It probably is the pan or pan gasket, but the puddle of fluid on my garage floor seems too transparent for oil.. so the only other guess I have is a coolant line, maybe head gasket but I haven't noticed anything that would suggest that.

all22s

if you already replaced your rear main seal, i'd imagine a new oil pan gasket was used. if you go through your receipts and don't see a new pan gasket that you were charged for, then i'd take it back to the shop and ask why wasn't a new pan gasket used?

CHRRRIS

Does the trans have to be dropped to replace the pan gasket? I'm guessing they figured it was the rear main or rear timing cover gasket so they did that first then if it wasn't they can replace the pan gasket without dropping the trans again..

rooster18

iTrader: (2)

im pretty positive you can replace it without dropping the trans but the k member must be dropped to replace it. have you ever broken the seal on the oil pan?? if so, they are bad about cracking if you aren't careful and lower all of the oil pan bolts the same and let it hang on one hole. mine was leaking at the oil pan right above the filter after my cam swap and my pan had a hairline crack in it. drained it, lowered it down, cleaned the sealing surface very good and put a little permatex on it and it sealed it right up. also, if you think it is coolant you can touch it with your finger and touch your tounge and if it has a sweetish type taste to it then it is coolant. just a little though. dont go gettin a big taste lol. hope this helps