lmfao I have this same leak right now on my lq4. I'm not leaking from the top of the engine and my bellhousing and fly wheel and bone dry inside.

edit: at least i think i do

 

So I just found out the GEN III downpipe to exhaust manifolds actually aren't the same as the GEN IV, or at least 6.2. Well the passenger side is the same as the GEN III at least which is the side that has the flared pipe end, which is on the left in the picture:

You can see the flat flange with the crush ring brass gasket on the right, they have different flange patterns from GEN III to GEN IV.

So I am trying to solve my dilemma of trying to keep my stock exhaust completely intact. Yes, its not a big deal if I cut the stock exhaust I can just (in theory at least, but I am not a good welder) weld the stock exhaust back together if I need to. My main thing was trying to keep it intact, so I can take it off and try to fab up my crossover and downpipe, then put it back together when I need to drive the truck since even if I got my downpipe and crossover put together and working I still have to fit up the intercooler and everything else. I also can't close my garage door since my truck doesn't fit so I have it open and I'm scared someone is just going to walk in and take everything I have.

Yes I know this is the price I pay, and you have to pay to play, and you can't cheap out, but we all know how hard it is to leave something stock.

Anyway I am missing the pipe size I need to run from the turbo turbine outlet to my stock exhaust, I plan to mate it at the factory ball and socket flange right after the transmission crossmember. And yes like with every other GM truck you have support the transmission and take the whole transmission crossmember out to get the factory y-pipe out in one piece without cutting. I got sent the wrong V-band size also and I couldn't find any pipe between 2.5 and 3 inches because of the covid apocalypse supply chain blame game thing.

I also would have figured they would have made some sort of turbo bypass blanking plate thing, that would bolt up to a T4 flange and then have a V band connection, which would let unbolt your turbo and put this piece in its plate temporarily. I looked all over for one, as well as just a simple block off plate that would bolt to a T4 flange but I couldn't find anything. This would be the only way I could think of doing this successfully, since I don't think I can drive anywhere above idle with no load on the turbo without overspeeding it?

 

So the pictures of my LQ9 Escalade I put in the end of this thread (whats the trick to make a cam sensor stop leaking? - Page 13 - PerformanceTrucks.net Forums) if you look back at them the leaks and oil droplets are literally in the exact same spots as what's on my L9H Denali.

This makes no sense, I mean there's no where else oil could come from that I know of, unless its a casting porosity issue, which I think I have heard of that happening before and I think there was maybe even a TSB about it.

 

Yeah my starter is oily and so is my oil filter. Oil is on the tranny as well but I popped the service cover off and it is bone dry in there so I am thinking it is not a rear main...

Just cleaned it with brake cleaner or else I'd take some pics

 

We have got to beat this leak I know we can. I tried UV dye on the Escalade and poured the dye into the crankcase but it never showed UV light ever, so it was weird. I may of just bough a cheap UV leak kit and maybe needed to buy a higher quality one though with a better and more powerful light.

 

I am thinking mine might be the cam position sensor

**** I do not want to pull the intake I just put back on less than 800 miles ago. I will be fuming

Edit: also want to say that the oil leak splashed all the way back onto my y-pipe which is strange. and to think this week I was gonna get my coilovers and shock relocation brackets *sigh*

 

I have a brand new, with a new oring too, BWD CSS1531 sensor if you want it?

 

After cutting all these angles and bends and making a bunch of pie cuts and I get the downpipe somewhat ok and after tacking it together and noticing my burnt looking welds, I noticed I left my gas bottle open, so $200 plus more wasted and I lost all my remaining morale at that point.

I am about to just buy a downpipe, but I can't find any steel ones, everything is stainless steel and I don't see the obsession over it, to me it looks ricery, when it seems you could save a lot of money with regular steel. If I buy a crossover and downpipe, I guess I would still have to cut the downpipe and weld in my cat. Anyone know where I could buy a crossover and downpipe? I know I could get a cheap Chinese ebay one, but it being stainless its going to be really difficult to weld for me.

I may have to just learn to TIG, I have a TIG welder but no gas for it. I am scared I will get leaks and never get it sealed up with my crappy welding skills especially with all the extra cuts and pie cuts I have.

 

stainless doesn't rust though

 

I feel aluminized has just as much rust protection, and I think stainless especially the cheaper 304 kind will lose its look after a few heat cycles and it will still rust. I don't live in an area where rust should even be a problem, but I still prefer the factory pipe look, I believe the factory exhaust pipes are aluminized.

I thought Trick Turbo sold a steel crossover but I couldn't find it on their website. I did notice though they sell the stock manifold flange, I wonder if it is the GEN III version or GEN IV version like I have. I am still wondering what changed between GEN III and GEN IV and for one why GM uses 2 types of connections at the driver vs passenger exhaust manifold and why they changed only the driver's side exhaust manifold on GEN IV from what it looks like to me. I know someone said GEN III and GEN IV manifolds are different even though they look similar from the outside.