Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

Larryjb

Full Access Member
Joined
Jul 21, 2016
Posts
1,161
Reaction score
1,087
If it is the RMS, you can read over this thread to learn from my experiences. I had previously done the oil pan gasket. FWIW, I've had no leaks since doing the job a couple of years ago, although my front cover seal is leaking. For this reason, given all the stuff that has to come off to get at everything, it doesn't take long to get the front cover off either, so it's worth it to do the RMS seal, rear cover seal (that's usually what actually leaks anyway), oil pan gasket, and front cover gasket. If your water pump is on the old side, I wouldn't reinstall an old water pump. Also, if you are doing the front cover, use a new thermostat. (use Permatex thermostat gasket sealer with the thermostat gasket. Mine leaked when done "by the book", and had to drain all my coolant again to redo the gasket.)


 

89Suburban

Bull in the china shop
Supporting Member
Joined
Jan 10, 2013
Posts
15,111
Reaction score
41,876
Location
SE PA
I have been battling a rear main seal leak for quite a while now. Anywhere I would park it would leave behind 4 or 5 2" circular drips on the ground. Oil pan was always covered with windblown oil, as well as the crossmember, front sway bar, transmission pan, etc. You can imagine how ugly my driveway and parking spaces in the street and at my work look. They look like grease pits. I was loosing about a pint a week at least.

I saw your post and checked out that Blue Devil Rear Main sealer you mentioned and review. I looked it up on Amazon and read those reviews as well. I have an original 5.3 with over 340,000 miles on it. I figured what the hell and threw a bottle in last weekend. Ran it for the week. I pulled it into my shop to do some front end work. I could not believe it when I climbed under there. There was 2 drips on the oil pan, 1 drip on the crossmember, trans pan was BONE DRY. And it did not leak ONE DROP onto the floor while in my shop. I still don't believe it.

You the man! I will update as time goes on. For right now I am FLOORED. I'm gonna hit the warehouse floor at my work tonight and do another drip test and post pics of before stains and after.

I just took a some pics of my decimated driveway and sidewalk, and the entrance of my garage where I parked this afternoon is the last pic, not one fresh drop right there from today. IMPRESSED.


View attachment 384550

View attachment 384552

View attachment 384551


Here is my shot at work on the warehouse floor. You can see the old stained spots easily. Now it’s just one new drop.



15AE121F-C722-495E-922F-8A32336F99BF.jpeg

1E8170C1-BE2D-4B87-87C4-BB426B0CBBAB.jpeg
 

Maximus05Escalade

TYF Newbie
Joined
Sep 26, 2022
Posts
24
Reaction score
37
I have been battling a rear main seal leak for quite a while now. Anywhere I would park it would leave behind 4 or 5 2" circular drips on the ground. Oil pan was always covered with windblown oil, as well as the crossmember, front sway bar, transmission pan, etc. You can imagine how ugly my driveway and parking spaces in the street and at my work look. They look like grease pits. I was loosing about a pint a week at least.

I saw your post and checked out that Blue Devil Rear Main sealer you mentioned and review. I looked it up on Amazon and read those reviews as well. I have an original 5.3 with over 340,000 miles on it. I figured what the hell and threw a bottle in last weekend. Ran it for the week. I pulled it into my shop to do some front end work. I could not believe it when I climbed under there. There was 2 drips on the oil pan, 1 drip on the crossmember, trans pan was BONE DRY. And it did not leak ONE DROP onto the floor while in my shop. I still don't believe it.

You the man! I will update as time goes on. For right now I am FLOORED. I'm gonna hit the warehouse floor at my work tonight and do another drip test and post pics of before stains and after.

I just took a some pics of my decimated driveway and sidewalk, and the entrance of my garage where I parked this afternoon is the last pic, not one fresh drop right there from today. IMPRESSED.


View attachment 384550

View attachment 384552

View attachment 384551
It floored me as well. I was just hoping for it to slow it down enough until i could take the time to fix it, which I will still repair it properly but dam it actually stopped it. Don't know for how long but have read that people have used it with oil changes after having success with it and never having another problem. I never had any faith in chemical repairs along with being scared of what the additive(s) may cause later. Glad it worked out for you.
 

Larryjb

Full Access Member
Joined
Jul 21, 2016
Posts
1,161
Reaction score
1,087
It floored me as well. I was just hoping for it to slow it down enough until i could take the time to fix it, which I will still repair it properly but dam it actually stopped it. Don't know for how long but have read that people have used it with oil changes after having success with it and never having another problem. I never had any faith in chemical repairs along with being scared of what the additive(s) may cause later. Glad it worked out for you.
Consider yourself lucky. It didn't stop mine.

Now, my leak was mainly from the rear cover, and that gasket is very thin and may not respond to such a product.
 

Maximus05Escalade

TYF Newbie
Joined
Sep 26, 2022
Posts
24
Reaction score
37
Consider yourself lucky. It didn't stop mine.

Now, my leak was mainly from the rear cover, and that gasket is very thin and may not respond to such a product.
I agree 100% on the lucky and do not look for it to last long at 255k my LQ9 still is as strong as ever but it owes nobody anything and anything could go at any time. On the brite side everything but the rear main and plate is new as far as gaskets, seals, oil and water pumps timing gears and chain etc. My brother is a GM mechanic of 30 years and was shocked at how little wear there was on the cam and crank mains as well as how clean everything is internally. we found no sludge or grit or medal in oil pan. Nothing has been done to the engine or transmission other then things listed, nothing major so far (knocking on wood). luck struck again when i got ahold of this year and model Escalade.
 

MassHoe04

Full Access Member
Joined
Nov 4, 2021
Posts
1,587
Reaction score
2,818
Location
Western MA
If it is the RMS, you can read over this thread to learn from my experiences. I had previously done the oil pan gasket. FWIW, I've had no leaks since doing the job a couple of years ago, although my front cover seal is leaking. For this reason, given all the stuff that has to come off to get at everything, it doesn't take long to get the front cover off either, so it's worth it to do the RMS seal, rear cover seal (that's usually what actually leaks anyway), oil pan gasket, and front cover gasket. If your water pump is on the old side, I wouldn't reinstall an old water pump. Also, if you are doing the front cover, use a new thermostat. (use Permatex thermostat gasket sealer with the thermostat gasket. Mine leaked when done "by the book", and had to drain all my coolant again to redo the gasket.)


FWIW -
I really liked the results when I used Fel-Pro gaskets on my 4.0L Jeep. I did valve cover, water pump and timing cover gaskets. Valve cover gaskets were metal and silicone. Water pump was made of fiber (paper?) with seals (silicone) already molded onto the mating surfaces. Timing cover gasket may have been all silicone (maybe one part was fiber with bead of silicone and another piece was all silicone... I can't remember on that one...).

The all get applied dry. RTV or other sealer is actually advised against in the instructions and may even void Fel-Pro product guarantees.

Not a leak out of any location. I would definitely recommend and would consider using again myself, if needed for my Tahoe.

Summit has individual gaskets and complete sets like these:
 
Last edited:

Maximus05Escalade

TYF Newbie
Joined
Sep 26, 2022
Posts
24
Reaction score
37
FWIW -
I really liked the results when I used Fel-Pro gaskets on my 4.0L Jeep. I did valve cover, water pump and timing cover gaskets. Valve cover gaskets were metal and silicone. Water pump was made of fiber (paper?) with seals (silicone) already molded onto the mating surfaces. Timing cover gasket may have been all silicone (maybe one part was fiber with bead of silicone and another piece was all silicone... I can't remember on that one...).

The all get applied dry. RTV or other sealer is actually advised against in the instructions and may even void Fel-Pro product guarantees.

Not a leak out of any location. I would definitely recommend and would consider using again myself, if needed for my Tahoe.

Summit has individual gaskets and complete sets like these:
All Fel-Pro for me as well with 100% success. As far as performance goes when I did knock sensors and replaced valley pan,0ps, valve cover and intake gaskets at the same time I found the intake had been leaking probably for years was leaking at every port of the heads. So, while I was chalking poor performance up to the engine just getting tired it woke right back up and runs stronger than ever now. The knock sensors really screw things up too, timing etc. but between the 2 it was like i put a new engine in. When I did water pump/oil pump, timing gears and chain, oil pick up etc. I replaced thermostat housing that was factory mounted to the new water pump. a year later or less I had to drain coolant and reseal the thermostat housing with Permatex. It had been leaking for a while but not enough to find it, so FOR SURE use sealant on thermostat/housing gasket.
 

Larryjb

Full Access Member
Joined
Jul 21, 2016
Posts
1,161
Reaction score
1,087
FWIW -
I really liked the results when I used Fel-Pro gaskets on my 4.0L Jeep. I did valve cover, water pump and timing cover gaskets. Valve cover gaskets were metal and silicone. Water pump was made of fiber (paper?) with seals (silicone) already molded onto the mating surfaces. Timing cover gasket may have been all silicone (maybe one part was fiber with bead of silicone and another piece was all silicone... I can't remember on that one...).

The all get applied dry. RTV or other sealer is actually advised against in the instructions and may even void Fel-Pro product guarantees.

Not a leak out of any location. I would definitely recommend and would consider using again myself, if needed for my Tahoe.

Summit has individual gaskets and complete sets like these:
The only FelPro gasket that has not worked so well was my rear diff, so they're not foolproof. I haven't yet tried retorquing, so that may be all that's needed. That said, the leak is much slower than the leak I fixed as I don't see any drips actually on the road when parked.

RMS gasket is supposed to be put on dry as you said. I did apply a little lube on mine before I fully read the instructions that it was supposed to be dry. However, my RMS appears to still be dry. Next on the list will be the front cover gasket.
 

RAMurphy

Bob
Supporting Member
Military
Joined
Oct 5, 2011
Posts
1,372
Reaction score
4,202
Location
S. Maryland
I'm a big AC Delco parts/gaskets supporter with a some exceptions. The intake Manifold gasket is one of those exceptions. The Fel-Pro intake manifold gasket cannot be beat. Once you use these you will not go back. If I can't get AC Delco - I will always turn to Fel-Pro.
 

Larryjb

Full Access Member
Joined
Jul 21, 2016
Posts
1,161
Reaction score
1,087
I'm a big AC Delco parts/gaskets supporter with a some exceptions. The intake Manifold gasket is one of those exceptions. The Fel-Pro intake manifold gasket cannot be beat. Once you use these you will not go back. If I can't get AC Delco - I will always turn to Fel-Pro.
I'm with you mostly on this one too, although I think Fel-Pro makes some of their gaskets so they are more forgiving. I can't say for sure, but in their advertising they say so. For example, Fel-Pro's head gasket allows for installation when the head surface may not be as perfect as a freshly machined surface. In the absence of a machine shop, for the DIY, Fel-Pro has advantages, at least in the specs they claim.

Unfortunately, that doesn't appear to have saved me on my rear diff gasket, but that may due to me needing to retorque.
 
Last edited:

Forum statistics

Threads
132,365
Posts
1,866,754
Members
96,986
Latest member
tmborske
Top