Jump to content

20 Sierra 6.2L rear main seal leak for the 4th time.

LilBean1982
 Share

Recommended Posts

LilBean1982 Enthusiast

LilBean1982

Posted
Posted (edited)

I’m new here so bare with me. I have a 2020 Sierra with the 6.2L. Back in November I was on the interstate and while passing a few vehicles my truck started smoking like crazy. I took the nearest exit and crawled beneath the truck and noticed engine oil was leaking from the rear main seal. At the time I had around 73,000 miles on the truck. I brought it to the dealership and they changed the seal which took them two weeks. The night I got the truck back I passed up a vehicle on a single lane highway and it happened again. So the next day I brought the truck back to the dealership again and they change the rear main seal in two days. Well this time it lasted about a week and it blew out again. So back to the dealership. 
 

This go round they did more test to figure out what the cause of the problem was and Found out that #1,7,&8 cylinder rings were bad which was allowing blow by into the crank case and was blowing out the rear seal. After having the truck for one month they decided to put in a new engine. I forgot to mention during that time the modifications I had were K&N cool air intake, airaid throttlebody spacer, Flowmaster exhaust, and superchips flash pac handheld tuner. 
 

After getting my truck back with the new engine everything was fine. I decided to gut out the cats and installed 02 sensor simulators to prevent the engine light from coming on. Well here we are 10,000 miles later and the rear seal has blown again. Same scenario of punching the gas to overtake a few vehicles on the expressway. I’m so frustrated. The 100,000 mile warranty on the new engine is now voided due to exhaust mods which I think is crazy. Can’t find anything online about others with the same issue. Has anyone here experienced or know of another situation like this? Any thoughts on what the cause could be. Thanks in advance. 

Edited by LilBean1982
Spelling correction and typos.
  • LilBean1982 changed the title to 20 Sierra 6.2L rear main seal leak for the 4th time.
LilBean1982 Enthusiast

LilBean1982

Posted
  • Author
Posted
15 hours ago, redwngr said:

Should have been voided with the tuner.

I removed it and installed the factory tune and they said nothing about it. 

Jay P Enthusiast

Jay P

Posted
Posted

You do know the ECM controls oil pressure & volume. It's possible your tune is the cause of the leak.

 

Jay

  • Like 2
redwngr Senior Enthusiast

redwngr

Posted
Posted (edited)
17 minutes ago, LilBean1982 said:

I removed it and installed the factory tune and they said nothing about it. 

That's kinda the point.

 

You make the truck do things gm didn't intend it to do and then expect them to pay for your screw up.

 

And because of the extra warranty work caused by you and others doing similar, GM's warranty costs are higher and we all get to pay more for our trucks.

 

 

I have absolutely zero issue with those that want to modify their trucks.

I do have an issue with expecting GM (and therefore the rest of the truck buyers) having to pay when it goes wrong. 

 

Imho, if anyone is to supply a warranty for mods it should be those that supply them.

 

There is no way GM should be expected to pay for issues due to someone else's 'engineering' (or lack of engineering) 

Edited by redwngr
  • Like 2
pokismoki Senior Enthusiast

pokismoki

Posted
Posted (edited)

usually a rear main seal blows out when the pcv and valve cover vents are plugged or not flowing enough air,  a few guys caused this issue by installing catch cans incorrectly . if you have a catch can remove it and see if the problem goes away,

Edited by pokismoki
SVG Enthusiast

SVG

Posted
Posted

Sounds to me like your seal blows when are passing somebody. Maybe drive in the slow lane??

 

Just kidding OP. Hope you can find out what's causing this.

Jeffnrivercity Enthusiast

Jeffnrivercity

Posted
Posted

I have blown 2 rear main seals..second one lasted 2 days...I also have a whipple and the canned carb tune...40k on truck and 20k on the whipple mod

Pretty sure i have ring problems too...contemplating my next step...

 

Lilbean1982, what did your cats look like when you gutted them, clogged at all?

 

 

LilBean1982 Enthusiast

LilBean1982

Posted
  • Author
Posted
10 minutes ago, Jeffnrivercity said:

I have blown 2 rear main seals..second one lasted 2 days...I also have a whipple and the canned carb tune...40k on truck and 20k on the whipple mod

Pretty sure i have ring problems too...contemplating my next step...

 

Lilbean1982, what did your cats look like when you gutted them, clogged at all?

 

 

The downstream O2 sensor on the driver’s side was throwing a code indicating that the corresponding cat was not working properly anymore. It appeared clogged somewhat and also discolored in some spots. The passenger side one never threw a code nor appear bad in any way. I’m considering upgrading the rings along with a few other engine components but would hate to spend all kinda money not knowing if there’s something causing the rings to go bad. I know I’m not the only person that has the flashpaq for the 6.2L but can’t find anything else online about similar issues. 

LilBean1982 Enthusiast

LilBean1982

Posted
  • Author
Posted
5 hours ago, redwngr said:

That's kinda the point.

 

You make the truck do things gm didn't intend it to do and then expect them to pay for your screw up.

 

And because of the extra warranty work caused by you and others doing similar, GM's warranty costs are higher and we all get to pay more for our trucks.

 

 

I have absolutely zero issue with those that want to modify their trucks.

I do have an issue with expecting GM (and therefore the rest of the truck buyers) having to pay when it goes wrong. 

 

Imho, if anyone is to supply a warranty for mods it should be those that supply them.

 

There is no way GM should be expected to pay for issues due to someone else's 'engineering' (or lack of engineering) 

I didn’t state anything about expecting GM to pay for the repair. I myself know that the exhaust mod would void the warranty. Don’t know what post you read but thanks for your unneeded response. 

LilBean1982 Enthusiast

LilBean1982

Posted
  • Author
Posted
5 hours ago, AirForceAngler said:

Here's my advice:  Quit Eff'ing with the tune and the truck!  Put cats back on it and leave it alone.  

It’s my truck. I will do as I please. I’m not complaining about anything nor expecting GM to repair it. I simply came here to see if anyone else knew of similar problems along with the cause or possible fix. Thanks for your two cents anyways. 

  • Thanks 1
LilBean1982 Enthusiast

LilBean1982

Posted
  • Author
Posted
5 hours ago, pokismoki said:

usually a rear main seal blows out when the pcv and valve vover vents are plugged,  a few guys caused this issue by installing catch cans incorrectly . if you have a catch can remove it and see if the problem goes away,

Thanks. I will look into this. 

LilBean1982 Enthusiast

LilBean1982

Posted
  • Author
Posted
5 hours ago, Jay P said:

You do know the ECM controls oil pressure & volume. It's possible your tune is the cause of the leak.

 

Jay

I realize that’s a possibility. That’s why I’m reaching out to see if there’s others out there with similar issues. 

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing

  • Latest Articles

  • Posts

    • Buckwild27
      Gas Prices

      By Buckwild27 · Posted

      I agree. 
    • Atlas
      Gas Prices

      By Atlas · Posted

      87 down as low as $5.14 here... winning!
    • Atlas
      Wow I'm in a pickle. (Broke down truck) and a story.

      By Atlas · Posted

      Progress... sort of.   Intake is disassembled, spider is out, fuel lines removed. Used a torch on the stripped screw with the lower intake off, much easier when I've got the intake sitting on my workbench, I made it talk. Walked right out with a pair of vice grips once it was nice and toasty hot.   New parts are piling up on my service cart waiting to be installed. Distributor, temperature sensor, new gaskets, fuel line kit, themostat, water neck.   My new pickle is I don't want to spend $600 on a replacement spider. I'm not sure IT is bad. I'm probably splitting hairs. Or it's $300 to send mine away and another 3 weeks of the truck just sitting. I have half a mind to assemble everything with the old spider to see if I can get away with just replacing the fuel pressure regulator to be safe. The obvious issue was the gushing high pressure fuel line which will be replaced. Getting to the spider really isn't that hard, and now I know what I'm doing , swapping it would be a breeze should it absolutely need one. Stupid, or smart?   The part that gives me pause is replacing the distributor. Well, it's already out. And I didn't mark it, whoopsie! Engine was at TDC when I removed it, I know that, so upon correct reinstall the metal tip on the rotor should point to the TDC mark on the distributor because that's where it was pointing on the old distributor. Worst case I'm a tooth off and have to re-stab it.   But then, what? I assume the truck will start. It doesn't appear the timing can be set. Here's the problem: These distributors can't be rotated but a degree or two, by design. What I read is Cam ****** needs to be -2 to +2 degrees, ideally at 0 (and checked/set above 1000 rpm). There should be enough wiggle to get that properly set, but checking the reported value is another potential issue. My Actron 9185 scanner says it supports enhanced GM PIDs and Cam ****** is one of them but it's unclear that I'll be able to correctly see it over OBD 1.5. I can see why people end up junking these things with life left in them. They're an absolute nightmare with tweener-year diagnostics/electronics and unobtanium parts.   Fingers crossed it starts and idles nicely. There can be hope, right? I'ma buy a lottery ticket the same day just in case.   Next steps..DO IT. I have not installed an intake before so I've been reading and watching a lot. Some say NO RTV except on china walls, some say DO RTV on water ports but not fuel/air intake. 1/4 or 3/8 bead on China walls? I think my strategy will be, obviously, RTV china walls with overlap on the gasket corners. Chapstick-style RTV the water ports. Leave intake ports dry. The only set of intake gaskets I could find locally are Edelbrock performance gaskets (uh...for an asthmatic 190hp V6? LOL) so we'll see how they do.   #NoToolLeftBehind. It took an hour, but my recovery mission for my deep 10mm socket was successful. It had rolled down the bellhousing and wedged itself between what I think are the fuel lines? I couldn't see it at all, but with a junk antenna I had laying around, I blindly went poking/sweeping for it, heard it clink, raised the truck, and caught a sliver glimpse of chrome with a flashlight way up there in Narnia. I had pushed it farther along the lines holding it captive, but within access of severely improvised tools, poking and cursing at it to finally knock it free to where I could get a fingertip on it to bring it home.    Not much to see.      
    • RyanbabZ71
      Gas Prices

      By RyanbabZ71 · Posted

      Thats crazy considering im right next door (Indiana)
    • Black02Silverado
      New Retail & Commercial Promo

      By Black02Silverado · Posted

      For a limited time, retail and commercial accounts receive an AMSOIL Vinyl Tool Tray with their order of $500 or more when they use code TRAY726 at checkout. The promotion runs through July 21, 2026.   Order at https://syntheticadvantage.com   Want to use AMSOIL in your business or sell at your store, apply here.  https://www.amsoil.com/business-opportunities/?zo=521390  

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...