[MagnumPI]

My beloved R has an annoying oil leak at the rear pan area. I have been under there cleaning and looking for the origin unsuccessfully. I found some posts here and on the Corvette Forum regarding this problem with some early LS2 engines. From what I have read there was a GM TSB about aluminum block porosity and rear main seals. Further research indicates that the porosity issue was rare but many LS2's benefited from changing the rear engine cover and pan gasket as well as the rear main seal (no small undertaking). I'm not sure if this is my problem but it certainly could be.... Everyone knows that chasing oil leaks is at least hit and miss and at most a huge expense. So here's my question: If there is anybody out there with any first hand experience on this issue, one, how likely is it that this is what is needed to fix this leak and two is it smarter just to keep wiping the floor and topping off the oil than to spend big bucks chasing this leak? At this point the leak is not bad enough to keep me from driving the vehicle however it will probably get worse. Any advice will be much appreciated.

 

[TXNSSR]

My beloved R has an annoying oil leak at the rear pan area. I have been under there cleaning and looking for the origin unsuccessfully. I found some posts here and on the Corvette Forum regarding this problem with some early LS2 engines. From what I have read there was a GM TSB about aluminum block porosity and rear main seals. Further research indicates that the porosity issue was rare but many LS2's benefited from changing the rear engine cover and pan gasket as well as the rear main seal (no small undertaking). I'm not sure if this is my problem but it certainly could be.... Everyone knows that chasing oil leaks is at least hit and miss and at most a huge expense. So here's my question: If there is anybody out there with any first hand experience on this issue, one, how likely is it that this is what is needed to fix this leak and two is it smarter just to keep wiping the floor and topping off the oil than to spend big bucks chasing this leak? At this point the leak is not bad enough to keep me from driving the vehicle however it will probably get worse. Any advice will be much appreciated.

Rear main oil leaks can happen as the miles pile up, or if it sat too long. Changing the rear main seal means dropping the trans, in a stick or auto. Seal is inexpensive compared to the labor. Had a friend take his to a trans shop locally and it cost $800. Afterward when he asked why it was still leaking, they informed him the pan was leaking too, and they’d address that for another ~$800. It was a real sad situation.

I’ve changed several pans to Corvette pans and it takes a while, and requires the LC32 crossmember, but isn’t bad. I’ve written the instructions for it.

I know some put an additive in with each oil change and they have no leak.

Most have the rear main seal changed when they change the torque converter or clutch as it is right there. I understand GM has an upgraded rear seal now.

At 75K one of mine has a very very slow drip. I can see it hang, but there is no “spot” on the driveway. I’m fine with it, until I’m dropping the trans for something.

Worth it? That is up to you.

 

[copper799]

While it I ALMOST a certainty that it is the rear main seal/pan gasket leaking, as this is a fairly common issue on the early LS2, you can trying cleaning the area with brake cleaner and putting some UV dye into the oil and see if that helps identify the source. Most folks just park over a piece of cardboard and live with the daily drop of oil until there is a reason to drop the transmission. If your leak is MUCH worse, it may necessitate a sooner repair. I am not a fan of ‘stop leak’ products, while some have reported some success, I just don’t see that route as proper repair and the question about it stopping up a vital sensor, port or galley just does not let me sleep well. Just ask me about an A/C system that I am currently overhauling because someone put Freon with stop leak into the system. This one costing the owner big $$ and is making me invent some new words .


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[6.0TOGO]

Recently had tranny failure at 230,000....While having it repaired we replaced the rear main seal as a precaution since I also had an oil leak....after reinstall of tranny my oil leak continued to be a problem....replaced the oil pan gasket...oil leak gone!!!....gasket $63.00....labor less thank $300.00....good luck!...Chuckstr

 

[SWT RYD]

The TOY has a small oil leak that only occurs when it is not driven. If it sits for a few weeks a drop or two is seen on the floor. Drive it regularly it doesn't happen. Maybe it's telling me it It doesn't like sitting in the garage. It's meant to drive 😂😂😂😂😂.🛻🛻🛻🛻.

 

[blue1]

This has been discussed before. I worked at Romulus Engine Plant where we made the first engines for our R's. I had a redline built as my co. car drive and by. Right as I received it it had a weep drip from rear seal. I asked my engineers at the time if I should get it fixed. This was after GM admitted the issue existed. They all mostly agreed unless it got worse, once motor is in vehicle it's better to live with it as more damage would probably be done trying to fix it, much less the expense. That was 17 years ago and it still weeps a drop or two occasionally. Hard to find a mechanic that I trust so I watch it , don't worry about it, but still wish it didn't. Just my two cents. PS. There are a lot of other issues on the R's that we can fix thanks to this group of fanatics.

 

[SWT RYD]

This has been discussed before. I worked at Romulus Engine Plant where we made the first engines for our R's. I had a redline built as my co. car drive and by. Right as I received it it had a weep drip from rear seal. I asked my engineers at the time if I should get it fixed. This was after GM admitted the issue existed. They all mostly agreed unless it got worse, once motor is in vehicle it's better to live with it as more damage would probably be done trying to fix it, much less the expense. That was 17 years ago and it still weeps a drop or two occasionally. Hard to find a mechanic that I trust so I watch it , don't worry about it, but still wish it didn't. Just my two cents. PS. There are a lot of other issues on the R's that we can fix thanks to this group of fanatics.

That brings up another question. Is this only a characteristic of the SSR or Do other LS motors have the same issue? Inquiring minds want to know.

 

[MagnumPI]

Thanks “blue 1” I think I’m going to keep driving and watching it at least until I need to have the trans pulled for a clutch or something.

And to”SWT RYD” , I don’t know about other LS motors but I think all the early LS2’s were vulnerable. The SSR motors were pulled tight off the Corvette assembly line and there is plenty about this issue in the Corvette forums

 

[Stlhotrod]

My Black 05 thinks it is a Harley or a male dog and thinks it needs to mark its territory by dropping some oil and transmission fluid where ever it goes. Because it is leaking both I will be swapping the transmission and doing the rear seal. While I am in there I will do the Corvette pan also. But I am in no hurry as this one doesn't get driven much so it may have to wait.

 

[SSReplay]

Small block Chevys have been leaking from the rear seals since I have been driving them starting in the mid 60's. Every one I have been under is at least moist around the rear and most with some miles on them, will leave a couple drops on the floor if you leave it parked for a few days.
My $.02 - if it doesn't leak so much that there's a puddle - keep driving and enjoying it - it's normal. If it bothers you and you have the time & money have it fixed!