• When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.

New chain cover causing oil leaks again, 383

Ray70Chrg

Well-Known Member
Local time
4:49 AM
Joined
May 23, 2019
Messages
673
Reaction score
983
Location
Scottsdale,Az.
Just completed, successfully, the replacement of the rear main seal. It shows no sign of leakage with the few times I have started the engine and let it idle for 20-30 minutes. Before I would certainly see oil trails coming down by the trans dust cover. I got a ton of advice from the "Official Rear main seal replacement" thread here. I had some issues with oil leakage at front and right side of oil pan and let it ride until I did the rear seal. Again, I went back to the oil pan threads and got great advice to put new gaskets and seal leaks. I also changed to a new 6 qt. hemi pan from 440 source. I was left with one persistent leak at the right forward bolt on the pan. Again, the great advice from this thread lead me to question the chain cover which I replaced last spring when I did a cam change. It was my 3rd attempt at gasket change that lead me to this only leak. It is a new Mahle that I installed dry except to rtv the 4 joints and I have only 50 in/pds. torque. 3 steps of 20,40, then 50 i/p. the photo shows how much space is left between top of gasket and bottom of chain cover. My question: What is the minimum amount of disassembly I need to do to get chain cover loose to adjust it. Thanks in advance.
CIMG1470.JPG
 
Last edited:
Are you saying you only have the oil pan bolts tightened to 4.2 ft/LB (50 in/LB)? The factory manual calls for 15 ft/LB (180 in.LB), but depending on the gasket used, I usually stop at 10 ft/LB to 12 ft/LB. The cork gaskets "spooge" out too much for my liking at the bolt points. I prefer the black cork-rubber Fel-Pro gasket myself. I would say that the low torque on the pan bolts is what is causing the leaks.
 
It's only leaking at this one place now and it's obvious, when looking at it, that the chain cover is not sitting properly. Yes the torque is on the light side for now but I think the chain cover needs to be addressed. On my other 2 attempts I brought the torque up to 150 i/p and the new pan was already dimpling and had to be hammered flat again. If too little or too much rtv causes leaks,than what is the right amount?
 
What is the minimum amount of disassembly I need to do to get chain cover loose to adjust it. Thanks in advance.

There is no adjustment. The covers position is controlled by two block dowels. So the cover should be in a fixed position.
 
Thanks pnora for replying. Yes it is fixed but others have had the same problem with new chain covers. I have read where some have just barely enlarged the dowel holes to give slight wiggle room to have the cover sit properly. The only other option is to keep ordering defective chain covers hoping you get lucky.
 
Thanks pnora for replying. Yes it is fixed but others have had the same problem with new chain covers. I have read where some have just barely enlarged the dowel holes to give slight wiggle room to have the cover sit properly. The only other option is to keep ordering defective chain covers hoping you get lucky.
The main thing is the balancer to seal fit. By changing the cover fitment to have it down lower you could be side loading the seal which will be another problem. I would find a good used cover and try that.
 
One other thought is the new pan you bought. That should be checked to make sure it is flat. The other thing is on the cover. That lower front flange should be flush with the bottom of the blocks pan rail. If it is than the cover is fine. Did your old pan leak in this area?
 
You have to watch the length of the lower timing cover bolts. If you have the wrong ones they can bottom out in the block. They'll feel tight and look correct, but won't clamp the cover against the lower front edge of the block. Its been a while since i had this issue. Can't remember if the proper bolt is 1/2" long and a 3/4" bottoms out. Or if 3/4" long is correct and a 1" bottoms out.
Doug
 
Hi Doug. I remember your posting about that and I'm going to check that in the morning. When I put this chain cover on a year ago, after changing cam, I had no knowledge of the bigger bolts being different lengths. So you're saying the shorter bolts should go in the bottom holes? It seems possible that I might be able to get the 4 (2 on each side) big bolts out without too much trouble. What do you think?
 
One other thought is the new pan you bought. That should be checked to make sure it is flat. The other thing is on the cover. That lower front flange should be flush with the bottom of the blocks pan rail. If it is than the cover is fine. Did your old pan leak in this area?
The old pan I had was the original 402 pan from 51 years ago. It would dimple very easily and I always had a leak or two with it. I figured the metal must have been fatigued after all these years. I guess the car had 164k miles on it and the odometer is going around for the second time. The condition of the interior told that story. When I got the new pan, I checked it for level on the granite counter top. It looked good to me.
DVW s post above has brought new info into play which I will check out tomorrow.Thanks
 
When I had the issue i just swapped bolts and fixed it. And all 4 need to be short unless there is a bracket being held by any of them.
Doug
 
ok, update on the 4 lower bolts on the chain cover. These are the larger bolts than the 4 above them, just to be clear. I took out the 2 lower bolts and the right side was shorter than the left. 1st photo.
CIMG1474.JPG
I took out the upper right side, because it was easier to get at, and it was short also. I measured the bolts, photos 2&3. I then measured the depth of the screw holes. The lower 2 measured at 1 inch and the upper one measured at 1 1/4 inch. I put the longer screw in the upper hole and the 2 shorter into the lower holes. It seemed logical. However, it didn't seem like either would bottom out regardless of where it went. I don't understand the logic of this because nothing else is attached to these bolts. I torqued all bolts to 120 i/p. Leak remained at same spot but not as bad as before. Will continue to add torque to see what happens. Don't know what to think about these 4 lower bolts and holes and their different lengths. Thanks for the help.
CIMG1475.JPG
Just to add, all 4 bolts had the same markings on the hex head and appear to be original.
CIMG1476.JPG
 
I am a little confused as always

I chased an oil pan leak for the longest time - Or so I thought - Make a long story short , when the factory timing chain cover was bolted down after a cam change on my 383 , the two dowel pin holes in the timing chain cover caught the dowel pins within the block , because the holes where not cleaned out proper , and when tightened down caused the timing chain cover to distort outward in that sealing area around the dowel pins

The oil would then work its way down to the oil pan gaskets/windage tray and flow backwards

Don’t ask me how many times I changed oil pan gaskets before I finally realized what the hell

Confusion

Your pointing to the timing chain cover bottom flange sealing area for the oil pan

Like stated earlier with pnora , especially if aftermarket , you need to figure out if that timing chain cover flange is FLUSH with the bottom of the block , and it definitely doesn’t look like it in that picture , and then look at your two oil pan bolts that attach the oil pan with this timing chain cover flange from underneath / above your K Member
 
Hey Guys, Thanks for all the help. I pulled the pan and the bottom of the chain cover is even with both sides of the block. It appears I did not do a good job of cleaning the block right where that right side forward screw is. Cleanliness is everything when doing this and I only did 95% job this time. Thanks again.
 
Auto Transport Service
Back
Top