New first gen owner

[Jairmee]

Hello, couple months ago I found myself a 1991 SHO. It’s currently leaking oil from the rear main seal and oil level sensor (ironic I know) but parts are on the way to fix it. It also has a low coolant light do to a failed coolant level sensor and unfortunately still hunting that part. Other than that it has run great and is a joy to drive! Joined in hopes of getting help and advice as time goes on when I need it.

 

[zoomlater]

Welcome! Looks great

 

[luigisho]

nice find. kinda missing a Gen I

 

[Irish Pride]

Welcome in.

Double check your oil leak diagnosis. It's not very common for rear main leaks.

-Chad

 

[Jairmee]

Welcome in.

Double check your oil leak diagnosis. It's not very common for rear main leaks.

-Chad

Two different shops confirmed it is the seal. And the same for the oil level sensor as well.

 

[Irish Pride]

Two different shops confirmed it is the seal. And the same for the oil level sensor as well.

The only way to confirm the rear main is leaking would be to pull the transmission. I would take anything a shop tells you with a grain of salt. These cars are not known for rear main leaks.

A friend of mine was told by three different transmission shops that his 93 needed a transmission when it ended up needing a VSS.

-Chad

 

[luigisho]

A friend of mine was told by three different transmission shops that his 93 needed a transmission when it ended up needibg a VSS.

Remember hearing something similar to this happening to someone many many years ago. Alot of misdiagnosis. Rear main sucks to change.

 

[Zpak]

Welcome, and congrats on the new ride.

 

[Bluezone]

Welcome

 

[luigisho]

How many miles on this thing?

Thinking ahead..if you are going to dig around under the car, drop the oil pan and replace the rod bearings while stuff is out of the way. Once the exhaust y-pipe is clear the oil pan drop is right there. It is a maintenance item anyway so get it off the list.

 

[Jairmee]

How many miles on this thing?

Thinking ahead..if you are going to dig around under the car, drop the oil pan and replace the rod bearings while stuff is out of the way. Once the exhaust y-pipe is clear the oil pan drop is right there. It is a maintenance item anyway so get it off the list.

157,000 though a lot has been done in the past 10yrs by two different owners (about $9k in work.) and I have nearly all 30yrs worth of maintenance records that were kept with it. I’ll need to see if that is something that has been done yet or not.

 

[FastCAD]

Two different shops confirmed it is the seal. And the same for the oil level sensor as well.

take what Chad say's seriously. I had purchased a new rear main seal some time ago after I got what was diagnosed as a rear main seal leak in anticipation for a future clutch replacement. The clutch replacement was recently done and the leak was actually the rear oil pan gasket causing a hassle and delay with having to source the oil pan gasket so, dropping the oil pan is a lot easier than dropping the trans. but in my case I was doing the clutch anyway so I replaced the seal even though there was (nothing wrong with it) just because I was already in there @ 225,000 mi.

p.s. I recently had a thread on this forum with Nick Grimes who sent me a photo of below the rear corner of the block above the pan gasket that was causing the leak due to a (design flaw). a little ultra black took care of that. U may also want to (consider) getting from shosource a set of the 'clevite' bearing end caps that are probably at the end of their useful life after 30 yr's. or so (check your previous build sheets).
best to ya & welcome.

 

[BaySHO Performance]

take what Chad say's seriously. I had purchased a new rear main seal some time ago after I got what was diagnosed as a rear main seal leak in anticipation for a future clutch replacement. The clutch replacement was recently done and the leak was actually the rear oil pan gasket causing a hassle and delay with having to source the oil pan gasket so, dropping the oil pan is a lot easier than dropping the trans. but in my case I was doing the clutch anyway so I replaced the seal even though there was (nothing wrong with it) just because I was already in there @ 225,000 mi.

p.s. I recently had a thread on this forum with Nick Grimes who sent me a photo of below the rear corner of the block above the pan gasket that was causing the leak due to a (design flaw). a little ultra black took care of that. U may also want to (consider) getting from shosource a set of the 'clevite' bearing end caps that are probably at the end of their useful life after 30 yr's. or so (check your previous build sheets).
best to ya & welcome.

I agree on the leak being the rear oil pan gasket rather than the rear main seal. They often leak, the rear main seal hardly ever. Here's my boilerplate on it:

If the leak is between the oil pan and transmission, the rear oil pan seal has failed. The factory puts the seals in dry. They eventually get rock hard, exposing a design flaw in the engine. Pic shows the front edge of the rear main seal carrier with the groove for the oil pan gasket. Notice that there's a small rectangular hole at the end of the groove. This is plugged with a tab on the gasket, but it eventually leaks from this point.

Solution is to put a dab of gasket sealer on the block where the ends of both gaskets sit. Dielectric grease helps the gaskets stay in place during installation.

 

[Jairmee]

I agree on the leak being the rear oil pan gasket rather than the rear main seal. They often leak, the rear main seal hardly ever. Here's my boilerplate on it:

If the leak is between the oil pan and transmission, the rear oil pan seal has failed. The factory puts the seals in dry. They eventually get rock hard, exposing a design flaw in the engine. Pic shows the front edge of the rear main seal carrier with the groove for the oil pan gasket. Notice that there's a small rectangular hole at the end of the groove. This is plugged with a tab on the gasket, but it eventually leaks from this point.

Solution is to put a dab of gasket sealer on the block where the ends of both gaskets sit. Dielectric grease helps the gaskets stay in place during installation.

View attachment 85960

I guess it’s worth spending a couple extra bucks and having them check it out one more time. Thanks for the explanation.

 

[BaySHO Performance]

I guess it’s worth spending a couple extra bucks and having them check it out one more time. Thanks for the explanation.

Trouble with having them recheck is that it's difficult to tell what is leaking without tearing stuff down. Oil is probably all over the place at the moment. The oil pan leak will be at the front corner of the oil pan, whereas the rear main seal will show itself at the very bottom of the transmission. Cleaning that whole area and driving around some until the leak is observed again is your best bet. I'd say a 90% likelihood that it's the oil pan.

Or you could to ask them to reseal the oil pan anyway, making sure that they use gasket sealer at the corners of both seals. Removing the oil pan or transmission are mutually exclusive jobs except for Y pipe R&R (1 book hour). Net of that, Oil pan reseal takes 2 book hours vs. rear main seal R&R 7 book hours.

At 157K miles, I suggest checking the rod bearings as well. They will be fine as long as copper isn't showing, but might as well change them anyway by way of preventative maintenance:

Rod Bearings (Set of 6) - Standard Size (89-95)

We currently have standard-size rod bearings IN STOCK, but we are unsure if we will be able to get more in the future. Rod Bearings are wear items, where the car's maintenance history has a serious impact on bearing longevity. Since some SHOs change hands a number of times, the history of the...

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