racecar

Why does my L92 have oil dripping off the starter. I replaced the pan gasket with the new part number gasket. Cleaned everything really good and siliconed the corners. I replaced the valve covers and gaskets, there is no oil leaks coming from the top of the motor. Behind the starter, there is no oil on the crank sensor, dipstick tube, main cap side bolts.

I have replaced everything except the rear cover and rear main seal. I used my LS6 rear cover on this new block. Is there difference in rear covers LS6 vs L92. Is there any difference in the gasket? The only thing left is to pull the trans and replace the rear main seal and cover gasket. That really sucks in a C5, but that is the only gasket left to replace.

Anyone have ideas, or gasket/cover information? Thanks, RC

LS3 G Body

Did you apply sealant to the starter bolts before installing them. This was discussed recently on the board. Oil is migrating down the bolt closest to the block.

racecar

Yes, I tried that and thought it was the solution. It doesn't leak until about 5000-6500 rpm, that's when it cuts loose and sprays onto the headers and really starts smoking. That's why I'm thinking it's the back of the motor, I have replaced evereything else.

FRUSTRATED T/A

iTrader: (13)

Do a leak down just to make sure you dont have to much blowby. To much would push some past some seals possibly. Just an idea to try.

1quickirocz

probably coming from the rear cover. GM has a bulletin out for block porrosity on the rear cover surface of the block...take some rtv and put it on the block and scrape it away with a rasor blade while its still wet...let the block sit for a while then reinstall the cover and you should be good to go. that process will push the rtv into the pores of the block surface.

racecar

That's what I am thinking, rear cover. I have the bottom of the bellhousing off. There is no oil on the flywheel but the inside of the bellhousing is covered with oil. It has to either be coming from the rear cover, rear main, or somewhere else and running into the bellhousing. I have checked or replaced everything else so I am going to pull the bellhousing and rear cover.

I plugged in a vacuum gage to the breather line and it had 25 inch vac at idle and even 1 inch at 6500 so I don't think it has crankcase pressure.

BlownVette 2001

iTrader: (2)

Check your pilot bearing (rear crank) as that is just a plug that sometimes get damaged doing clutch jobs.

racecar

I thought of that one too. If it was leaking there, the clutch would be covered with oil. That's what is strange, the clutch and flywheel are clean, but the bellhousing is a mess. I have seen motors with a leaking rear main, and flywheel is covered with oil. Not mine, so I am thinking it is the rear cover gasket.

Have you pulled the trans out of a C5? Do you pull the trans on the crossmember, or seperate them. Pull the drive tube with the trans, or seperate??

Whistler

iTrader: (46)

Mabye take it for a drive with the vaccum gauge hooked up, and see if CC pressure builds with sustained RPM under load?

racecar

See post #6, still had vac at 6500.

Whistler

iTrader: (46)

I saw that... that was with the car stationary blipping the throttle, correct?

BlownVette 2001

iTrader: (2)

Yeah, I have pulled out a few transmissions, etc....


- jack up the car if you don't have a lift. (Drive up some ramps on the front) and then jack up the rear and secure with jack stands.
- remove the center console, unbolt the shifter.
- Disconnect the clutch hydraulic line (you need a special tool) however a 15mm open end wrench works if you don't have the tool) You'll see a white collar around the joint, push in and remove (disconnect the line).
- Pull the rear tires
- Disconnect emergency brake cables from the hubs (15mm) 2 bolts each.
- remove the rear calipers, by taking off the 15mm bolts and hang them up with some bungie cords, do not disconnect the brake lines.
- Remove the center exhaust pipes.
- Remove the two rear upper "A" arms and shocks.
- Get a jack under the transmission and remove the (4) rear cradle bolts.
- let down slowly and stick a jack and block of wood under the oil pan to prevent the engine from tilting back to far and cracking your firewall. I always remove the intake manifold for peace of mine as it gives you a lot more clearance.
- Unbolt the 13mm bolts up by the bell housing that holds the torque tube tube in place.
- Now in the rear you'll notice that the brake lines are secured to the cradle using plastic keepers that you'll need to remove along with wire connectors that hold the tranny harness.
- Disconnect everything and slowly go down checking to make sure you have diconnected everything.
- The tranny harness slides off to the drivers sides.
- Lower the rest of the way and pull back gently to remove the assembly.


If you're going to be removing the bell housing I would remove the intake to give you room to work in there as the top bolts are really difficult to get too.

As always disconnect the battery before starting. If you have headers, you'll probably have to lossen them up to get the bell housing off.

Be carefull when removing the torque tube to not hit the brake and fuel lines on the drivers side of the tunnel.

Pauls416Z

RC - I used my LS6 front/rear covers along with new LS6 gaskets and seals in both covers and no issues with oil leaking.

I looked at some photos of my L92 before I installed it:
There is a block plug above the starter and a bolt in the block behind the starter.
Did you install the knock sensors on each side, one just in front of the starter?

Any chance it could be your oil pan and the air movement under the car is blowing it up on the starter? Are you using the "batwing" pan or something else?

What is your oil pressure and temperature when the engine is warmed up?

Sorry you are having trouble....

racecar

Whistler; that vac reading was on the road at WOT, 1 inch vac.

BlownVette; Thanks for the input on puling the trans, that's exactly what I was looking for, great.

Paul; I have knock sensors on both sides, I can't tell exactly where the oil is coming from. I have an LS6 Corvette oil pan, yes, the wind is blowing it onto the starter, and back into the bellhousing, or blowing it out of the bellhousing. That's the real question. Is it blowing in, or out. Now I am thinking it is coming out of the bell hsg.
Oil temp and pressure are fine 210 degree and 60 lb at WOT.

OUTLAWZ RACING

iTrader: (9)

check the valley cover again, The pressuer in the case may push it out and let it trinkle down the rear. How about the oil pressure sending unit ?

BlownVette 2001

iTrader: (2)

How much oil are you losing ?

racecar

Not losing a big volume, just enough to leave a 6 inch spot on the floor after an hour of hard runs through the country. After running hard on Sunday, and smoking real bad from oil leaking, there was a big spot on the floor next day.

I had the intake off several times to check the oil pressure sensor and valley. I had to make my own aluminum gasket for the sensor, the OEM kept leaking. Also had a leaking sensor, but all is clean now. I may pull the intake tomorrow to double check, before pulling the trans.

Whistler

iTrader: (46)

Yeah you definately dont want that on your clutch!

Did you do the assembly of the covers on the engine?

racecar

Yes, I built two other LS6 motors for this car, and they never leaked a drop. This L92 makes great power, but I can't run it WOT without it spraying oil on the headers.
I ordered a new rear cover, seal, and gasket, I hope that it makes a difference.

1lejohn

iTrader: (9)

It sounds to me that you are pressuring up the crank case at the high rpms. I would check the pvc system first. Then you might want to do a leak down on the motor and see if you have a bad cyl.(one thats not sealing well). I had a engine that had a small chip in the piston ring land it would blow oil out of the dip stick.