1sickz51vette

Okay guys I think I figured out why the clutch is chattering intermediately, and may be a big problem..... On a 600 mile road trip to and from Miami, i randomly smelled motor oil burning only every once and awhile though. Seems like only when passing vehicles at highway speeds though above 90 mph you can smell it every once and awhile coming from my car. My guess is that the rear main seal is now leaking intermediately, and I never had any issues before AAMCO installed my clutch/flywheel. They will not warranty the "clutch" work from what he told me, but I know for a fact my car never leaked any oil because when it was pulled apart I even seen the old clutch disc and inside the bell housing. There are no serious leaks as I can't see any oil physically dripping, just the smell of burning oil inside the car every once and awhile at highway speeds only. What should I do at this point, is the seal just going to completely let go very soon? Why would it only be leaking at higher speeds as well? It's only turning 2000 rpms at highway speeds, but the actually vehicle speed seems to have an effect on the burning oil smell. I just recently had my oil changed with 6 qts mobile one 10-30 which I always run, and I checked the oil as soon as I got home, still at the full mark. I'm beyond frustrated with this place and I know everything needs to come back apart to replace the rear main! Will this slight drip or whatever is going on ruin my new clutch disc? It is not slipping or anything at this point. I have read online that installing the flywheel incorrectly can damage the seal, and I'm guessing this was the case as I had no leaks or burning oil smell before whatsoever. Opinions? Thanks guys.

1sickz51vette

Did some more research and the only thing else i could think of would be that the oil pressure sensor may be leaking/going bad? The car has 127k miles on a completely stock motor, and I noticed the oil pressure which is usually 25 psi at idle has dropped down to 19 psi at a hot idle after long trips on the highway yesterday and recently. Hopefully it is just the sensor going bad, but even at 2000 rpms it has 38 psi according to the gauge. The reason I was thinking the rear main seal was because I been having clutch chatter intermittently since the recent install and it seems i only smell it on the highway at 90 mph (exactly 2000 rpms) and there is a slight vibration in the shifter at that speed. Any ideas?

Choreo

I was in a full panic a few months ago when two mechanics told me it was my rear main - turned out to be my OPS.

1sickz51vette

I've been the same way freaking out over this. I have replaced the oil pressure sensor once about 40,000 miles ago maybe even more. I seafoam the top end every other oil change as well so I doubt it is the pcv system? If it is the OPS going bad again, I guess now is my chance to pick up an LS6 intake manifold. *fingers crossed* Just find it weird I only smell it on the highway at a certain speed!

littlefranks

also if motor has cam sensor in back ,o ring goes bad from heat and builds up oil and drips down the side of rear cover.is it a ls1 or ls6 engine?

1sickz51vette

It's a 97' LS1. Hope it is just a sensor, but my gut feeling is telling me it is the rear main. Can it be messed up installing the flywheel?

Bill Curlee

Not installing a flywheel... Unless you install a flywheel really weird...

If it were me,,,,, I would wash down the rear of the engine with copious flushes of brake parts cleaner and make sure everything is clean. Jack up the car, wipe down everything that you can see and make it nice and clean.

Take the car for a 60 min or so drive, bring it back and see if you can see any new oil leaks.

A front seal oil leak (which is more common for leakage) can coat EVERYTHING and make it look like a rear main seal leak!! Trust me.. Been there.

1sickz51vette

Thanks Bill you are the man! I don't see any leakage under the hood area whatsoever or from the valve covers, I keep it pretty spotless under there. I'll have to try the mirror trick with a good flashlight to examine the back of the intake manifold area very shortly. No leaking oil from the bellhousing area at all. I believe whatever oil is leaking is being burned up instantly. It's weird the only time I smell the burning oil is at 90 mph or above, and exactly at 90 mph my engine is turning 2000 rpms & there is a vibration in the shifter to where it almost "rattles". Wonder if something is off balance causing it to leak at certain speeds?

Bill Curlee

Carefully examine the PCV system on your engine. There are parts of the PCV lines that can deteriorate and leak

Under certain conditions, you can have crancase vapors & OIL excaping the PCV System.

Here is what your PCV junction looks like behind the manifold.. It has been known to deteriorate and crack:



You can also see the cam sensor and oil pressure sensor in the same shot:

1sickz51vette

Thanks again Bill, that's the money shot right there! I will give her a good look over in the am and report back. *Fingers Crossed* Also noticed you are from Gales Ferry, not too far from our old place up there in Colchester!

Choreo

The first time my OPS failed - the reading on the gauge maxed because the sensor itself failed. I then had my engine replaced under warranty and the mechanic transferred my 2nd OPS to the new engine. For the first year or so, no issues, then one day oil started dripping off the bolt next to my oil filter. There was oil on my bell housing and exhaust. Oil pressure gauge read normal. 2 mechanics got underneath and both said it was the rear main seal.

I finally tore into the problem myself and the OPS was leaking through the threads where it enters the block - probably not torqued properly or sealed properly when they transferred it? There was an oil puddle around the sensor, but I am guessing the sensor itself was probably fine, but just to be double-sure I replaced it with a new sensor - no problems now for over a year.

LoneStarFRC

There's a lot of your problem right there. I would not send my worst enemy to those clowns.

I agree with the others about the liklihood this oil smell is either from your OPS or even your pcv hose(s). Remember, your fresh air intake plenum is located immediately behind all these items at the base of the windshield. Right by the wipers. Pretty common for various smells to be able to enter the car from there, even with the hood seal, especially at highway speeds.

FWIW, Anti-Venom Performance is only 1 1/2 hour drive North of you in Seffner, right outside Tampa. They specialize in Vettes and F-bodies. By reputation, they do good work, and know what they're doing. If I lived in PC, I would either give Greg a call or possibly check into some of the other Vette or performance shops in the Tampa/St. Pete area. Maybe someone else can recommend other shops in the area as well.

1sickz51vette

Thank you, I looked behind the intake and there was no physical oil dripping from the hoses, except this plastic piece where a hose connects it has some dirty oil residue on it. None whatsoever elsewhere. Maybe some Vapors are leaking out of here, what do you guys think?

Choreo

This is what I found around my OPS...

Bill Curlee

Well,,,, considering the age of the car, the issues your having, and the residue your seeing,,,,,,,, I recommend removing the entire PCV line set up and make sure its not cracked/deteroriated.

BC

Supercharged111

Have you jacked up the car to look underneath? I realize if it's dripping from the top the bottom will be wet anyway, but that'd be my first move.

1sickz51vette

I took a good look under the car and no leaking oil that I could see. Seems to only be leaking at a certain speed and burns up instantly. My guess is if it was indeed the rear main seal it would be burning up when it hits the hot clutch disc or flywheel?

Supercharged111

More likely if it were the rear main seal it'd just drip straight down on your driveway. The seal is in front of the flywheel, so there's not that great a chance of it getting in your clutch unless it were a real gusher, in which case it would leave enough evidence to easily identify. So it seems unlikely to me at least from what I've read that it's the rear main. No drips from the bellhousing then? Are you sure you smelled oil burning or perhaps just the exhaust stinking when you put your foot down?

1sickz51vette

It has that distinct burning motor oil smell! Is it possible that something is off balance and at a certain speed the vibration is causing the seal to weep slightly? I did have the flywheel machined .0250"

littlefranks

pull the cam sensor out change o ring.you wont see oil on top it is behind bell housing and fills ip a pocket and drips down side of rear cover.ijs