I have a Small Oil leak from inbetween the engine and tranny, There is a small Opening there and oils comes out of there, I know it is Engine Oil and not Transmission oil because its golden like the Engine and tranny oil on my car is red. It runs from the front of the engine down to that Opening or it looks like it is, I cleaned it with Engine cleaner and My repair guy checked it out. He told me isnt the seal between the engine and tranny. Could it be something else. BTW it's a 91 g20 with Auto Tranny.

Did he pull the tranny to check the seal? If not, find another mechanic.

To locate an oil leak, add flouresant(sp) dye to the oil, run the engine till it starts leaking (mileage will vary before it leaks!). Then use a blacklight to trace where the oil leak is flowing from.

Originally posted by se-r sam
Did he pull the tranny to check the seal? If not, find another mechanic.
you make like its so easy to remove the tranny just to check the rear main seal. If the distributor seal and valve cover gasket is fine, obviously the only other source would be the rear main seal. If its a minor leak, theres no point in removing the tranny just to fix that seal, it wouldnt be very cost effective.

highmilageg20 - Its mostly likely the rear main seal, distributor seal, or valve cover gasket. The rear main seal is impractical to change unless you plan to change your clutch. Try checking the beneath the distributor against the cylinder head and side of motor. If you see a leak, replace the distributor seal. The seal itself cost less than $5 and only takes 2 minutes to replace. Ohh and dont forget to check the valve cover gasket, an oil leak from there could also leak in between the engine and tranny.

Very good advice... I agree.

Since I am a mechanic-in-training, I think the mechanic here is a bit too quick to dismiss the rear seal. If it is seeping out of the bottom of the bell housing, I'd think the real main is more than likely the culprit.

Just my $.02...

Originally posted by slipper
you make like its so easy to remove the tranny just to check the rear main seal. If the distributor seal and valve cover gasket is fine, obviously the only other source would be the rear main seal. If its a minor leak, theres no point in removing the tranny just to fix that seal, it wouldnt be very cost effective.

I guess it depends on how you look at it. I mean, eventually, oil is going to get on the clutch surface and require a clutch disc chage. Depending on how many miles he has on the car, it might be worth it to open it up to fix the seal before it ruins a recently installed clutch. If it's an old/original clutch, then leave the leak alone until you do the clutch.

Curt B. Shumaker

Ever have your upper oil pan removed? If it was done by a monkey like myself, then the rear main seal retainer could be cracked where the oil pan sealing surface is. If you forget to remove the two little nuts under that cover on the oil pan next to the bellhousing and pull down on the oil pan thinking "why in the heck won't this thing come off?" it could be cracked. That's a much more obscure problem though. The odds are simply for the rear main seal itself which does require removal of the tranny, clutch, and flywheel. I could do it in an evening :), but for someone who has never done a clutch job before it would be a very daunting task.

Did no one notice that it is an automatic tranny? so there is no clutch involved...:D :p

Originally posted by slipper
you make like its so easy to remove the tranny just to check the rear main seal. If the distributor seal and valve cover gasket is fine, obviously the only other source would be the rear main seal. If its a minor leak, theres no point in removing the tranny just to fix that seal, it wouldnt be very cost effective.


1) It's not a question of being easy, but a question of being able to properly diagnose the problem.

2) Distributor seal and VC gasket would not leak out from the weep hole in the bellhousing. Besides, you could see it leaking down. I don't think HighMileageG20 and his mechanic are total morons. They'd notice it.

3) There is indeed another possibility. There are caps for the oil galleys, and while I've never heard of one leaking, it's entirely possible.

Originally posted by slipper
highmilageg20 - Its mostly likely the rear main seal, distributor seal, or valve cover gasket. The rear main seal is impractical to change unless you plan to change your clutch. Try checking the beneath the distributor against the cylinder head and side of motor. If you see a leak, replace the distributor seal. The seal itself cost less than $5 and only takes 2 minutes to replace. Ohh and dont forget to check the valve cover gasket, an oil leak from there could also leak in between the engine and tranny.

It's almost certainly the rear main seal.

On a slushbox equipped car, I probably wouldn't bother to replace it unless it leaked at least a quart every week or two. On a manual it's another story. Then again, my G20, when NA, had a rear main leak and I didn't replace it for a couple of years. Then I replaced the whole engine with a DET. :D

Originally posted by Geo91SER
1) It's not a question of being easy, but a question of being able to properly diagnose the problem. Thats the exact reasons i posted the possible culprits, being an auto mechanic, you cant automatically assume something is wrong without diagnosing. check the vc gasket, then the dist seal, NOW you may assume the rear main seal is bad!

Originally posted by Geo91SER
2) Distributor seal and VC gasket would not leak out from the weep hole in the bellhousing. Besides, you could see it leaking down. I don't think HighMileageG20 and his mechanic are total morons. They'd notice it. i never did say it is gonna leak out of the hole on the bottom of the bellhousing. if they are leaking it may cause some confussion and lead a mechanic or person to think that its automatically the rear main seal. again, read my first quote. Theres is nothing wrong with spending 2 minutes to look. In fact my friend recently replaced his clutch and complained about oil leaking in that area, but guess what, the culprit was the dist seal!

Originally posted by Geo91SER
3) There is indeed another possibility. There are caps for the oil galleys, and while I've never heard of one leaking, it's entirely possible. the oil galley plugs are easily visable and..."I don't think HighMileageG20 and his mechanic are total morons. They'd notice it." yes that may be a problem, but very highly unlikely. you say is so perfectly, "would not leak out from the weep hole in the bellhousing". if you dont get it now, im only using this to prove your post wrong....yes it may be possible but no one is perfect and may over look it and yes it may leak in that vicinity and cause confussion.

Originally posted by Geo91SER
It's almost certainly the rear main seal. again, you cant be 100% sure that is the problem if you dont look at the car, thats why i was explaining the other possibilities

Originally posted by slipper
Thats the exact reasons i posted the possible culprits, being an auto mechanic, you cant automatically assume something is wrong without diagnosing. check the vc gasket, then the dist seal, NOW you may assume the rear main seal is bad!

i never did say it is gonna leak out of the hole on the bottom of the bellhousing.


No, but HighMileageG20 said that was were the oil was coming from. Didn't you read his post?

Originally posted by slipper
the oil galley plugs are easily visable and...


No. They are not. They are hidden behind the bellhousing and indeed behind the flywheel. I just verified this by looking at my spare engine on the stand in my garage.

Originally posted by slipper
"I don't think HighMileageG20 and his mechanic are total morons. They'd notice it." yes that may be a problem, but very highly unlikely. you say is so perfectly, "would not leak out from the weep hole in the bellhousing".


Again you are wrong. Given the location of the oil galley plugs, if they were leaking the only place this leak would be detected (with the engine and gearbox in the car) would be by oil leaking from the week hole.

Originally posted by slipper
if you dont get it now, im only using this to prove your post wrong....

Well, you failed completely.

Originally posted by Geo91SER
No, but HighMileageG20 said that was were the oil was coming from. Didn't you read his post?like i said earlier, oil from the other areas may make it hard to determine the exact location. would it be had to spend a couple minutes to verify the location of the leak? or would you rather spend a couple days replacing the tranny to find that the rear main seal is not bad? didnt you read my post?



Originally posted by Geo91SER
No. They are not. They are hidden behind the bellhousing and indeed behind the flywheel. I just verified this by looking at my spare engine on the stand in my garage. ok i thought u were talking about the little ball bearings that are pressed into the side of the block



Originally posted by Geo91SER
Well, you failed completely. i sure wouldnt want you to "fix" my car! i have worked at a couple shops and any mechanic knows that it would be idiotic to fix a car without diagnosing the problem. im only helping the guy with the other possibilities, are you saying that its completely unnessecary to check the other items?

Originally posted by slipper
like i said earlier, oil from the other areas may make it hard to determine the exact location. would it be had to spend a couple minutes to verify the location of the leak? or would you rather spend a couple days replacing the tranny to find that the rear main seal is not bad? didnt you read my post?


Yeah, I read your post. It's silly.

Originally posted by slipper
ok i thought u were talking about the little ball bearings that are pressed into the side of the block


Have you ever even really worked on these engines? There are no ball bearings pressed into the side of the block. There are freeze plugs for the coolant passages. There are hex head pipe plugs for the oil galleys. The head has some plugs pressed into it, but they aren't ball bearings or anything like it.

Originally posted by slipper
i sure wouldnt want you to "fix" my car! i have worked at a couple shops and any mechanic knows that it would be idiotic to fix a car without diagnosing the problem. im only helping the guy with the other possibilities, are you saying that its completely unnessecary to check the other items?

Whatever. I'm not going to argue with you - especially since you don't know what you are talking about and are trying to make up for it with attitude.

Originally posted by Geo91SER
Yeah, I read your post. It's silly. so your saying its silly to check? highmilageG20 is asking us what different posibilities it could be, i am just informing him. your post are silly!



Originally posted by Geo91SER
Have you ever even really worked on these engines? There are no ball bearings pressed into the side of the block. There are freeze plugs for the coolant passages. There are hex head pipe plugs for the oil galleys. The head has some plugs pressed into it, but they aren't ball bearings or anything like it. yes there are, pressed on the front side, look on the front side near the radiator. since the SR20 motor is casted, they use drills to make the oil passages and plug the end with a ball bearing. sometimes these leak and are recommended to be drilled out and replaced with set screws and loctite when rebuilding.



Originally posted by Geo91SER
Whatever. I'm not going to argue with you - especially since you don't know what you are talking about and are trying to make up for it with attitude. i dont know why your getting all upset about this post. your first reply to me yuo stated "1) It's not a question of being easy, but a question of being able to properly diagnose the problem." but you contradict yourself by automatically ruling out the valve cover gasket and distributor seal!

It is very easy to rule out the distributor seal and valve cover gasket. Just clean up underneath them if necessary, drive the car for a day or so, and then check directly underneath of these things. If you still have oil coming from between the tranny and engine, it's the rear main seal.

Why are you even considering ball bearings and freeze plugs at this point? Only if you have replaced the valve cover gasket, distributor seal, and rear main seal would I even fathom these items leaking. The rear main seal on these cars can leak. It's kind of common.

Stay in the ball park before you can rule out the ball park.

Geeze... take a break guys. I know it's easy to get caught up in your own point of view and take things the wrong way... You're both getting too personal. I think you'll both agree the focus should be on helping the owner fix his problem.

Unless you're looking at the engine, it's impossible to tell where a leak is really comming from. It's perfectly sensible advice to look over the entire engine and make sure it's really comming from the bell housing weep hole. If the rest of the engine is clean, then you can proceed from there... so HighMilage, is the rest of the engine clean? Are you absolutly sure it's leaking from the bell housing and not just draining down to that point?

Originally posted by Yosho
Geeze... take a break guys. I know it's easy to get caught up in your own point of view and take things the wrong way... You're both getting too personal. I think you'll both agree the focus should be on helping the owner fix his problem.
exactly, im only trying to help the owner, geo is automatically ruling out the dist seal and valve cover gaskets, but those can easily be the problem. i dont think removing a tranny to fix a rear main seal or oil galley plug would be wise until you make sure the other items are not leaking.

Originally posted by slipper
yes there are, pressed on the front side, look on the front side near the radiator. since the SR20 motor is casted, they use drills to make the oil passages and plug the end with a ball bearing. sometimes these leak and are recommended to be drilled out and replaced with set screws and loctite when rebuilding.

Please provide photos. I have a spare engine in my garage on the stand and referenced it before responding. There are noball bearings sealing oil galleys on the left side of the engine (the side facing the radiator). There are two small plugs on a head oil galley on that side of the engine, but they are not ball bearing seals. AND they are just that much farther from the leak. Perhaps you'd like to suggest checking the front seal.

As for getting upset.... I'm not so much upset as losing my patience. You make statements about proving me wrong, yet it is you who are wrong. If you are going to keep making such claims, you'd better start getting your ducks lined up, because right now you have them scattered all over the ballpark. :D

Maybe you guys can take the "pissing match" to private mail? At this point the owner has heard each of your ideas/suggestions. What's left is you guys going back and forth about who is "right."

Curt B. Shumaker