Replace rear cover or leave alone?
Thread Starter
Launching!
Joined: Mar 2006
Posts: 285
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From: Indianapolis, IN
Replace rear cover or leave alone? I'm in the middle of changing the clutch and I noticed what I'd consider a SLIGHT amount of oil residue at the top of the rear cover (see picture). No oil residue was on the back of the flywheel. I tightened all rear cover bolts back to spec and moved on with installing the new clutch, but now I'm second guessing myself.
Should I install a new rear cover or just leave it alone? I've seen a ton of horror stories on here with people replacing the seal (in my case that's not leaking) or the cover w/ seal and afterwards they get leaks that weren't there before.
Should I install a new rear cover or just leave it alone? I've seen a ton of horror stories on here with people replacing the seal (in my case that's not leaking) or the cover w/ seal and afterwards they get leaks that weren't there before.
Thread Starter
Launching!
Joined: Mar 2006
Posts: 285
Likes: 0
From: Indianapolis, IN
In the top right area that had oil residue (within the bell housing), I didn't see anything other than the cover that could be leaking. Above the bell housing, everything is dry.
Look at the red circle, you can see the open area that houses the cam sensor. There is an o-ring on the lower end of the sensor that seals the bottom of that area. I doubt there's "pressure" there, but prolly a lot of splash.
11 Second Club
Joined: Dec 2008
Posts: 322
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I did mine yesterday. If you go for it it's not that bad. Used the Dorman piece and no special tools.
Placed on engine, installed a few guide bolts just a couple threads in. Pressed cover on. Snugged bottom half of cover bolts in criss cross pattern and spun the crank over a few times with a socket on the front. Snugged all bolts down x cross, spun crank. Tightened lower half bolts x cross, spun crank. Tightened all bolts x cross, spun crank.
The crank spinning is to continually help center the crank seal while you seat the cover. Tightening the lower bolts first is also said to be key to help seal it. Drove it around a few miles and not a drip.
Placed on engine, installed a few guide bolts just a couple threads in. Pressed cover on. Snugged bottom half of cover bolts in criss cross pattern and spun the crank over a few times with a socket on the front. Snugged all bolts down x cross, spun crank. Tightened lower half bolts x cross, spun crank. Tightened all bolts x cross, spun crank.
The crank spinning is to continually help center the crank seal while you seat the cover. Tightening the lower bolts first is also said to be key to help seal it. Drove it around a few miles and not a drip.
Thread Starter
Launching!
Joined: Mar 2006
Posts: 285
Likes: 0
From: Indianapolis, IN
Is that a common area for oil seepage? I didn't notice that hole there and now I'd have to take the bell housing and clutch off to check.
Thread Starter
Launching!
Joined: Mar 2006
Posts: 285
Likes: 0
From: Indianapolis, IN
I did mine yesterday. If you go for it it's not that bad. Used the Dorman piece and no special tools.
Placed on engine, installed a few guide bolts just a couple threads in. Pressed cover on. Snugged bottom half of cover bolts in criss cross pattern and spun the crank over a few times with a socket on the front. Snugged all bolts down x cross, spun crank. Tightened lower half bolts x cross, spun crank. Tightened all bolts x cross, spun crank.
The crank spinning is to continually help center the crank seal while you seat the cover. Tightening the lower bolts first is also said to be key to help seal it. Drove it around a few miles and not a drip.
Placed on engine, installed a few guide bolts just a couple threads in. Pressed cover on. Snugged bottom half of cover bolts in criss cross pattern and spun the crank over a few times with a socket on the front. Snugged all bolts down x cross, spun crank. Tightened lower half bolts x cross, spun crank. Tightened all bolts x cross, spun crank.
The crank spinning is to continually help center the crank seal while you seat the cover. Tightening the lower bolts first is also said to be key to help seal it. Drove it around a few miles and not a drip.
Based on the photo I attached, do you think it's necessary to replace the cover/gasket?
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11 Second Club
Joined: Dec 2008
Posts: 322
Likes: 1
I did put RTV at the lower corners and a thin line across the whole bottom where it meets the pan. I tightened the pan bolts last, as I remember from doing a cam swap on my GTO that with the front cover, if you don't hit the pan bolts last, you risk cracking the pan or cover or what not. However, maybe I did it bass ackwards, I didn't look it up to verify.
I can't tell from the pic how bad it is, but for me leaking is leaking. Mine looked to be darkest in that top pass side area too although I think mine was seeping at the near the bottom of the cover too. It's such a pain in the *** to get to, that I just did it. I had 79,500mi on mine and it was "due" by my reckoning.
I can't tell from the pic how bad it is, but for me leaking is leaking. Mine looked to be darkest in that top pass side area too although I think mine was seeping at the near the bottom of the cover too. It's such a pain in the *** to get to, that I just did it. I had 79,500mi on mine and it was "due" by my reckoning.
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Launching!
Joined: Mar 2006
Posts: 285
Likes: 0
From: Indianapolis, IN
I ordered the new rear cover with seal already pressed in and gasket/bolts (12639250) to address the leak above that appears to be from the high pressure area of the cover.
Is this the correct installation procedure for the rear cover / seal assembly?
1. Clean crank, block and oil pan mating surfaces with brake cleaner. Ensure clean and dry.
2. Put RTV on the block/oilpan interface only where the ends of the rear cover will sit ('T-joint).
- GM recommends 12378190, but I don't see an aftermarket alternative. Which is preferred/better: Permatex Ultra Grey or Ultra Black or something else??
3. Install seal/cover assembly over crank using plastic alignment tool that comes with it.
4. Install front cover bolts finger tight / snug, but loose enough that rotating the crank can still center it. Use Loctite 242 blue threadlocker / sealant on threads.
5. Install two oil pan bolts finger tight / snug. Use Loctite 242 blue threadlocker / sealant on threads (per Helms)
6. Spin crank two full revolutions.
7. Lightly tighten two oil pan bolts to 60 in-lb
8. Spin crank two full revolutions.
9. Torque oil pan bolts to spec: 106 in-lb
10. Torque cover bolts to spec: 18 ft-lb
11. Re-Torque oil pan bolts to spec (2nd pass): 106 in-lb
12. Re-Torque cover bolts to spec (2nd pass): 18 ft-lb
Let me know if this process sounds OK. Is there an official process for installing this assembly? My Helms manual only listed the process to install each component. Since GM sells the assembly, I'm assuming there must be some kind of official process from them.
Thanks in advance for any feedback.
Is this the correct installation procedure for the rear cover / seal assembly?
1. Clean crank, block and oil pan mating surfaces with brake cleaner. Ensure clean and dry.
2. Put RTV on the block/oilpan interface only where the ends of the rear cover will sit ('T-joint).
- GM recommends 12378190, but I don't see an aftermarket alternative. Which is preferred/better: Permatex Ultra Grey or Ultra Black or something else??
3. Install seal/cover assembly over crank using plastic alignment tool that comes with it.
4. Install front cover bolts finger tight / snug, but loose enough that rotating the crank can still center it. Use Loctite 242 blue threadlocker / sealant on threads.
5. Install two oil pan bolts finger tight / snug. Use Loctite 242 blue threadlocker / sealant on threads (per Helms)
6. Spin crank two full revolutions.
7. Lightly tighten two oil pan bolts to 60 in-lb
8. Spin crank two full revolutions.
9. Torque oil pan bolts to spec: 106 in-lb
10. Torque cover bolts to spec: 18 ft-lb
11. Re-Torque oil pan bolts to spec (2nd pass): 106 in-lb
12. Re-Torque cover bolts to spec (2nd pass): 18 ft-lb
Let me know if this process sounds OK. Is there an official process for installing this assembly? My Helms manual only listed the process to install each component. Since GM sells the assembly, I'm assuming there must be some kind of official process from them.
Thanks in advance for any feedback.
11 Second Club
Joined: Dec 2008
Posts: 322
Likes: 1
I think color dye is the only difference in high temp RTV. I used grey because black was sold. I've used orange before too.
The process looks sound, just make sure you tighten the lower half of the cover bolts first. In the thread about the special tools, there is a video of them doing a cover with a tool and you can see that he's only got the low bolts in. On the GTO site a professional engine builder also stated final tightening on the low bolts first as well so that's what I did. Still no leaks.
The process looks sound, just make sure you tighten the lower half of the cover bolts first. In the thread about the special tools, there is a video of them doing a cover with a tool and you can see that he's only got the low bolts in. On the GTO site a professional engine builder also stated final tightening on the low bolts first as well so that's what I did. Still no leaks.