H3 Engine Mount?

[Rocky Rotella]

I have a 2014 Yukon Denali and after 130,000 miles, it appears that the driver's side engine mount has let go. I plan to purchase a stock replacement from my local GM dealer but read on the forum that the Hummer H3 mount may be a better alternative.

When compared to the original engine mount, what makes the H3 mount a better choice?

And does anyone have a GM part number for the LH engine mount for the H3 application?

 

[Joseph Garcia]

The H3 mount is a stronger mount, and I do not believe that it has the cushioning that the stock Denali mount has (less motor vibration transferred onto the frame). It is the cushioning that goes first.

Other folks will chime in with more details.

 

[camaroz2887]

The factory mounts are filled with a fluid to dampen engine vibrations which after they leak are about useless lol. Some kind of hydraulic fluid maybe?

The h3 mounts are all rubber and metal, and much less prone to break. However you may notice more vibrations. I did this last summer and didn’t notice a large difference.

ACDELCO #25847739
Is the part I used.

 

[Rocky Rotella]

Thanks, guys. I wonder if it's worth replacing both sides?

 

[iamdub]

Thanks, guys. I wonder if it's worth replacing both sides?

I would and did. Both mounts are the same age, but the driver's side gets pulled on rather than compressed like the passenger's side, so it tears first. You're already under there and have the engine supported by a jack when replacing one, so half of the work is already done for the other side.

 

[petethepug]

The H3 mount is made for a 5.3 motor engineered for 300hp, mot 403/417 of the GMT900 Denali, some Tahoe & Escalade chassis runs.

Like brakes and suspension components, the motor mounts should be replaced in their entirety as serviceable parts.

You can’t cheap out and hope replacing one mount will have the same lifespan that the original three did when the vehicle was new. Fluid filled mounts are superior in reducing vibration. Downgrading to sold mounts is, well ... downgrading.

Make sure you get your tech or service writer to record “in writing” that the heat shields will be replaced too. Some places like to leave them out because they damage them during the install. Set the expectation up front, if they won’t put in in writing, prepare to walk.

Don’t allow your new mounts to get cooked because you have a lazy tech. Missing heat shields or replacing only one mount is a major cause of a short lived mounts. They’re only as strong as the weakest mount.




Sent from my iPhone using Tapatalk Pro

 

[iamdub]

The H3 mount is made for a 5.3 motor engineered for 300hp, mot 403/417 of the GMT900 Denali, some Tahoe & Escalade chassis runs.

Like brakes and suspension components, the motor mounts should be replaced in their entirety as serviceable parts.

You can’t cheap out and hope replacing one mount will have the same lifespan that the original three did when the vehicle was new. Fluid filled mounts are superior in reducing vibration. Downgrading to sold mounts is, well ... downgrading.

Make sure you get your tech or service writer to record “in writing” that the heat shields will be replaced too. Some places like to leave them out because they damage them during the install. Set the expectation up front, if they won’t put in in writing, prepare to walk.

Don’t allow your new mounts to get cooked because you have a lazy tech. Missing heat shields or replacing only one mount is a major cause of a short lived mounts. They’re only as strong as the weakest mount.




Sent from my iPhone using Tapatalk Pro

They are superior in reducing vibration, but only for a limited time. In my experience with mine, the vibrations were only very slightly more noticeable. Even then, it was only at idle. IMO, those slightly, virtually undetectable increased vibes are no loss of comfort when compared to the pain of replacing hydraulic mount(s) multiple times over. It's an engine mount- it's primary function should be to mount the engine securely and reliably. I'd pick that over turning it into a marshmallow to comfort a snowflake's heinie. Solid rubber mounts, some smaller than the factory ones, have been used for over a century, even on race cars with well more than 400 HP. GM sacrificed longevity of the mounts rather than resolving the vibration issues.

 

[petethepug]

100% correct on longevity vs performance in regard to the service life of fluid filled dampeners for on the 6.2L

It’s definitely pay to play with this GM part. A spotty history of reliability if replaced one at a time vs. when installed new of the production line makes them not for everyone.




Sent from my iPhone using Tapatalk Pro

 

[thompsoj22]

They are superior in reducing vibration, but only for a limited time. In my experience with mine, the vibrations were only very slightly more noticeable. Even then, it was only at idle. IMO, those slightly, virtually undetectable increased vibes are no loss of comfort when compared to the pain of replacing hydraulic mount(s) multiple times over. It's an engine mount- it's primary function should be to mount the engine securely and reliably. I'd pick that over turning it into a marshmallow to comfort a snowflake's heinie. Solid rubber mounts, some smaller than the factory ones, have been used for over a century, even on race cars with well more than 400 HP. GM sacrificed longevity of the mounts rather than resolving the vibration issues.

Snowflake's heine? Denali is a marshmallow off the showroom floor? Sounds like "little ****** syndrome" to me! lol, So if i install H3 mounts in my denali i can drive down the road knowing that clint eastwood is under the hood? lol! Honestly to each their own, I am a OEM purist and get my jollies by trying to replicate/maintaine how the vehicle performed when it was new and "as designed". Reducing vibration especially at an "idle" means alot to me when it's late at night and im at a red light idleing and the only thing that lets me know there is an engine running under the hood is the tach! My vote is as above, replace all three mounts with OEM and plan on another 100k miles out of them! Hey iamdub im just messin with ya! you definitley know what your doing and your opinion should be considered good advice. no disrespect intended. The YUKON DENALI XL is pure road limo!

 

[iamdub]

Snowflake's heine? Denali is a marshmallow off the showroom floor? Sounds like "little ****** syndrome" to me! lol, So if i install H3 mounts in my denali i can drive down the road knowing that clint eastwood is under the hood? lol! Honestly to each their own, I am a OEM purist and get my jollies by trying to replicate/maintaine how the vehicle performed when it was new and "as designed". Reducing vibration especially at an "idle" means alot to me when it's late at night and im at a red light idleing and the only thing that lets me know there is an engine running under the hood is the tach! My vote is as above, replace all three mounts with OEM and plan on another 100k miles out of them! Hey iamdub im just messin with ya! you definitley know what your doing and your opinion should be considered good advice. no disrespect intended. The YUKON DENALI XL is pure road limo!

I agree- Use only OEM H3 mounts. The parts store mounts are known to fail prematurely as well, although usually not as quickly as the factory hydraulic mounts.

I get not screwing with what highly educated engineers designed. But, even they are ultimately overruled by bean counters and have to make compromises and even cut corners.