Leak from oil cooler block off plate - GM LS 6.2L

[RonRonnster]

I've been chasing an oil leak from the oil cooler block off plate on my Yukon's 6.2L LS based engine. I'm now on my second replacement gasket and it has started seeping again clearly between the block off plate and the oil pan. The first repair lasted about a year - I used a thin bead of RTV that time. This second time lasted about 6 months. I did not use any RTV sealer this time. Both repairs were using the thin metal gasket that is now sold, instead of the original type that was thicker, and had a small rubber seal. Is there some trick to this that I'm missing? Do I need thread sealer on the two bolts? I though maybe it was rear main leak instead but after pulling the inspection cover on the transmission bell housing it's bone dry in there. It also seems to clearly be beading from the bottom of the block off plate.

Any LS engine owners dealt with this before? Here's a picture of the old style gasket (that can apparently no longer be found):

Here is the new style that I've been using. Note that it appears the old style is available online, but they send you the new style. I thought I was getting the older style this last time but I did not - I got this, which is a very thin metal gasket:

Any input or insight is much appreciated!

 

[GMBoy]

Last time I did one of those 6.2L gaskets I used "the right stuff" gasket maker around it both sides - no leaks so far, been 2 years.

https://www.permatex.com/products/g...s/permatex-the-right-stuff-gasket-maker/

 

[Trav]

Some Euro cars also use these steel coated gaskets and they work fine most of the time. When they do have issues its usually due to corrosion on one of the aluminum parts usually the cover.
Clean it well, remove any corrosion and coat both sides with Hylomar, it will never leak again. If I had to use Silicone sealer (my least favorite product) I would use the Ultra black, it is more oil resistant than the right stuff, curing time is longer but it works better with oil.

 

[P10crew]

Op I just recently got the gasket shown in your top pic from gm. I ordered it for an 02 6.0

 

[RonRonnster]

P10 - where did you order from and do you have a part #? Most part numbers I've found are all superseded with the new design but maybe there is still some old stock out there or a different part number I need to find.

 

[RonRonnster]

Trav - is this the stuff you are talking about?

Hylomar Blue 172-148 Universal Gasket Sealant 3.5 oz Tube https://www.amazon.com/dp/B00J4Z7N9I/ref=cm_sw_r_cp_api_i_aOvxEb462RTA8

 

[Trav]

Yes you can use that one or the "M" or any of them really, it is just the difference in the thickness of the compound. I use the M mostly, best stuff I ever used, I don't use silicone much anymore unless it is OE spec'd for an application that requires extreme gap filling.

Hylomar M

 

[P10crew]

I got it from Texas speed and I got another one from my local dealer. They May have been old stock????
They were both in GM bags.

 

[P10crew]

Another thing I should mention. I'm sure yours is stock but it may very well be warped ..... check it with a straight edge. I always lay mine on piece of sandpaper on a flat surface and lap them flat... you may be surprised. That is a very important passage for your engine oiling system so don't let a bunch of sealant ooze in there when you tighten it down.

 

[Mullick2001]

I haven't been 9n BITOG in years but for some reason this post popped up on the front page of my google news feed. Strange...

Since I'm here I got my gasket from Texas speed about a month ago and got the old revision. Might be worth a call to them as they probably stock a lot if them.

 

[RonRonnster]

I pulled off the block off plate to check for any issues with the gasket or surface and found some very slight low spots on the block off plate - almost like corrosion or something. Just to be safe I ordered a new block off plate. I found a billet one from ICT that includes a rubber gasket for $12 so I gave that a shot. So far so good, I like that the gasket is replaceable and the plate is solid and good quality. Looks like it belongs on a hot rod, but should do the trick.

 

[clinebarger]

The oil pan gasket is prone to leak/seep right above the Oil Cooler feed/return.