6.2L (L9H) Owners - Get all your questions answered here

[wyefox]

Well after 315.5K miles I decided the 2010 NHT Silverado had reached the end of its service life, so I just traded it for a 2019 GMC Sierra Denali - would never give up the 6.2!  Mobil One exclusively, 5 set of tires, brakes at 265K, shocks, etc. at 285K and it was still getting 18 mpg!

[RyanbabZ71]

Well after 315.5K miles I decided the 2010 NHT Silverado had reached the end of its service life, so I just traded it for a 2019 GMC Sierra Denali - would never give up the 6.2!  Mobil One exclusively, 5 set of tires, brakes at 265K, shocks, etc. at 285K and it was still getting 18 mpg!

I may be doing the same in 19 (Chevy to GMC AT4)


Ryan B.

[wyefox]

5 minutes ago, RyanbabZ71 said:

 

I may be doing the same in 19 (Chevy to GMC AT4)


Ryan B.

 

I was concerned about dropping the rear from 3.73 to 3.23 in the 2019, but the 10-speed transmission seems to make up the difference.

[RyanbabZ71]

I was concerned about dropping the rear from 3.73 to 3.23 in the 2019, but the 10-speed transmission seems to make up the difference.

I didn’t have the NhT so I have the 3.23 currently.


Ryan B.

[Kbzeluck]

_{New to the 6.2L.. Picked up an 08 Sierra Denali AWD with 123k miles a couple months ago. Believe it's L92... Kooks LT and hatless Y pipe and intake will be going on soon. Cant stand looking at them in the garage lol. Plan to get a blackbear tune.. Be happy to just get 14 MPG on the highway lol.} 

[rae61]

Hello,

 

I recently found this thread as I was looking for information on the 6.2 L9H I have in my 2010 Avalanche. Great read and lots of solid information on this fun to drive engine!

My other Avalanche and Tahoe have the 5.3, while good and very reliable... Tahoe has 228k miles and still is strong the power of this 6.2 in super nice!

 

Rick.

[SierraHD17]

I'm late to the party but it took me a long time.  I went through 12 of the L9H trucks over the course of 10 years including a 2010 I factory ordered and left on the lot because for lack of better words... they were pathetic for power.  This 2013 I picked up is definitely not.. but it's a weirdo 6.2 powered extended cab LT with basically no interior options other than being an NHT optioned truck with 3.73s.  This little low mileage gem is sitting at about 45000 miles and I am going to give it a cam and headers to start.. should be a good improvement.

 

I am pulling the engine though to do my cam swap... I want the oil pan off and pull the pressure relief gm has plumbed in above the oil filter out and toss it.  I can't stand that thing limiting oil pressure to 55 pounds... and wouldn't doubt it leaks constantly and it's why i see these 25 to 30 psi hot idles when the gen 3s have no problem maintaining 40 psi at idle.  That's just me though.

Edited February 28, 2019 by SierraHD17

[vSoutherner]

Hey all, just picked up a 2011 Yukon XL Denali with 130k+ on it. There's been a little back and forth with the dealership I bought it from because I noticed a bolt backing out on the driver side motor mount they replaced. I also noticed an oil leak and had it back up there twice. The shop they brought it to two said it was the cooler lines but I noticed if I crank it cold and let it idle there will be a small drop in the driveway 10 minutes later. It looks like its coming from up top but the valve covers look fine. The oil pressure seems ok, are these known to leak from the oil pressure sensor at all?

[diyer2]

Where is the oil drop on the drive in relation to the motor?

Is the oil drop near the front of the motor, back, drivers side, passenger side?

Find that out and start looking around on that area of the motor.

 

[vSoutherner]

On 3/12/2019 at 2:19 PM, diyer2 said:

Where is the oil drop on the drive in relation to the motor?

Is the oil drop near the front of the motor, back, drivers side, passenger side?

Find that out and start looking around on that area of the motor.

 

I thought I had it pinned down to above the oil cooler lines because that's typically where I see the drop. What confused me is I see a small amount on what I think are transmission cooler lines going up the other side of the bell housing. I guess I could take an inspection camera and put in down the back toward the oil pressure sensor I just didn't know if it was typical to see a leak from there. The leak looks like it starts fairly high up.

[Gamios]

I’m not sure if I’m doing this right but I’m need of desperate help regarding my 2011 Chevy Silverado.

The AC has been turning on and off randomly . We also noticed when this occurs the passenger window can’t be rolled down and makes a weird sound when we try. 

 

Its got a brand new evaporator which we recently had done I want to say about two months ago at Autonation Chevy where we purchased the truck. It’s a $2000 job!

 

Took it in and waited 3 hours only for them to tell me that the AC was working just fine and they couldn’t find any problems! They even drove the truck for 15 mins and it didn’t act up on them!

 

Anyone have any idea what could be causing the AC to randomly shut on/off and for the passenger window to not work as well?? The AC dashboard lights also go dim when this happens! I want to figure this out and point it out to these damn mechanics!

 Thanks so much

[Bartamus]

On 11/29/2011 at 7:24 PM, RyanbabZ71 said:

Tell tale sign of a 6.2 (single rear exit exhaust passenger side)

 

 

Its more of a sport suspension.

 

(Z60) High-Performance Suspension Package

What would a tune run on the 6.2 price wise

[swathdiver]

1 hour ago, Bartamus said:

What would a tune run on the 6.2 price wise

Contact BlackBear Performance and see what options are available for yours.

[Irishwelder45]

I'm having some electric issues with my 2011 Denali didn't know if anyone could help me out in here. My FM radio skips every 10 to 15 seconds which is annoying. My battery died so when I replaced it I completely lost my time clock and can't figure out how to get it back. And my left turn signal blinks fast like there's a bulb out but all bulbs are good checked every one and the connection. 

[dsmmace]

Check the ground wires at your Bcm.