Broken Motor Mounts

[iamdub]

I don't know, and don't know the differences between LT, LS, etc. I do know 350's have been around a lot longer than '97 though.

I see where the confusion is. I'm speaking of just the variants of Gen 3+ ("LS" blocks). The Gen 2 and older are irrelevant in my mind. lol

Comparing apples to oranges, I'd say the mounting points being divided over four points is due to the thinner walls of the LS.

 

[Meccanoble]

Just an update. Mounts can make a big difference in truck performance. Low end feels so much faster. I'm in love with the truck all over again at 208k miles.

 

[1BADI5]

I said F U to the OEM mounts and went with the Atomic solid motor mounts........alittle vibration is well worth it. Plus they have a "can't break them warranty"

 

[Hmj7819]

So I just returned from my mechanic after a routine oil change and he shows me I have a cracked drivers side motor mount!!!! WTF... I mean seriously GM? You would think they would install a strong enough motor mount for what people use these SUV's for. My mechanic ony works with GMC and Chevy's and he said he is noticing this often.

Has anyone else experienced this problem?

Oh and cause where it is located, not the cheapest of repairs either..

Yes, I have an 07 Tahoe Z71. I’m on my 3rd motor mount, 2nd replacement. The first time one broke I had it replaced at a shop. I know the guy who owns it so the cost wasn’t terrible ( more than I usually pay however because I do a lot of my own work). However, he said it was the first and last one he would ever do on an SUV 4x4 because of the difficulty. When the second one broke I was on the way to NC from SC for my granddaughters birth. It was Jan a year ago. I had to get some chain and bolts from Tractor Supply to make a temp fix until I got home. I replaced the driver side mount myself with very minimal issues other than that always present 1 difficult bolt towards the firewall. I am in complete agreement with you that the amount of wear and tear these things are obviously under they should have made them better. So good luck and if you plan on keeping this vehicle for a while just expect it not to be last one.

 

[Hmj7819]

I have changed mine two times already. My 2008 Denali has 138k miles.

I’m with ya, I’m on my 2nd replacement. Mine is an 07 with 150,000.

 

[Hmj7819]

I know exactly how it is going to go....I'm going to pay my mechanic $425 to replace it. I went to my local GMC dealership today to get a price comparison and he was very honest with me and said he would charge $500.

On a different note I casually asked him if they are helping customers with cracked dash boards and he said they are splitting the insurance cost with the customer and it will cost me $500 to fix.

Jonathan what year is yours? Just asking because I’ve had the same issue with my dash being cracked and now has a huge hole above my steering wheel across that dome over the instrument cluster.

 

[Hmj7819]

Got it. Other than that test, since I have a lube/oil change coming up soon, will my mechanic be able to tell, visually, that a mount is broken, or is it tough to visually diagnose?

yes any mechanic worth their weight in oil will be able to tell you if it’s broken whether your break is visible or not. Mine makes a loud roaring noise at take off (acceleration) that you can hear for about 2 seconds at initial take off from a stop. As well as you can see the front end of the vehicle raise on one side or the other when torque is high.

 

[Rocket Man]

Yes, I have an 07 Tahoe Z71. I’m on my 3rd motor mount, 2nd replacement. The first time one broke I had it replaced at a shop. I know the guy who owns it so the cost wasn’t terrible ( more than I usually pay however because I do a lot of my own work). However, he said it was the first and last one he would ever do on an SUV 4x4 because of the difficulty. When the second one broke I was on the way to NC from SC for my granddaughters birth. It was Jan a year ago. I had to get some chain and bolts from Tractor Supply to make a temp fix until I got home. I replaced the driver side mount myself with very minimal issues other than that always present 1 difficult bolt towards the firewall. I am in complete agreement with you that the amount of wear and tear these things are obviously under they should have made them better. So good luck and if you plan on keeping this vehicle for a while just expect it not to be last one.

Use the Hummer H3 passenger side mount on both sides of yours like mentioned in this thread and never have to worry about it again. It’s not fluid filled like all these that keep failing are.

 

[Hmj7819]

I've got the same issue on my 2007 Yukon XL Denali. I'm considering replacing the driver's side motor mount myself.

One concern is supporting the engine without jacking on the oil pan (manual advises against due to concern of damaging oil pump pickup). How are you supporting the engine while you pull the mount? From above with an engine hoist? Is there somewhere below where you can safely jack the engine?

I did my driver side myself a year ago. Glen5437 is correct you can use a board to take pressure off and support it with a jack. I understand why they say not to but as long as your attentive and easy it’s fine. There’s a lot of things I’ve read and heard about using a jack from beneath but I think most of these are scare tactics. This is where a little common sense goes a long way. I did loosen both the other motor mount and trans mount also. I jacked the engine up just enough as there’s not much clearance for more without damaging something. Be sure before you let the jack down and tighten everything that there’s no pinched hoses wires etc and it’s sitting back where it needs to go. I had some major shifting with mine because of how long I went before I figured out what my issue was and repairing it.

 

[Hmj7819]

Use the Hummer H3 passenger side mount on both sides of yours like mentioned in this thread and never have to worry about it again. It’s not fluid filled like all these that keep failing are.

is this one that has more vibration noise and vibration?

 

[avalonandl]

The LS engines are pretty smooth running I doubt the increase in vibration will be noticeable.

 

[Rocket Man]

is this one that has more vibration noise and vibration?

I doubt you’ll notice. It’s the same type, solid rubber, that the previous generation has. The ones that have noticeably more vibration would be the the solid aftermarket mounts that have no rubber at all, like the ones made by Atomic Fab. And none of them cause noise lol.

 

[iamdub]

Use the Hummer H3 passenger side mount on both sides of yours like mentioned in this thread and never have to worry about it again. It’s not fluid filled like all these that keep failing are.

This is what I don't understand- If the original one broke and the replacement (or even the replacement's replacement) broke in short order, why keep paying to install the same?

 

[iamdub]

is this one that has more vibration noise and vibration?

If there is any detectable increase in vibes, they will only be when idling. I promise you, possibly feeling a shake ever so often at idle is far less painful than replacing the mount once or twice or thrice...

 

[Rocket Man]

This is what I don't understand- If the original one broke and the replacement (or even the replacement's replacement) broke in short order, why keep paying to install the same?

I know huh

 

[Fless]

I know huh

The definition of insanity is doing the same thing over and over again and expecting a different result. (Quote is sometimes attributed to Albert Einstein but that's not been proven.)

 

[Greg Kulbick]

Good info in this thread, I just ordered an H3 mount for the 07 Tahoe my wife is driving. I'll be glad to have that fixed.

 

[KMeloney]

Please report back on your results with the H3 mount.

 

[Greg Kulbick]

Successful install. Toughest part was getting the right combination of extensions and wobble. Most surprising thing was how much more I had to jack the motor up to fit the new one in. Don't turn wrenches much anymore, I'm gonna hurt tomorrow.

 

[22YukonDenali22]

Hey All,

I've read enough to know to go the H3 route! My 2008 Yukon Denali RWD's passenger mount is bad...but the driver's side is completely fine?? I thought usually it was the other way around? Maybe the driver's was replaced by a previous owner (I've owned it for 25k miles, it now has 97k on it). I can't see a part number on the driver's mount, other than a circle with a "15" etched on one side. I did the brake test... In drive, no engine movement; in reverse, the passenger side jumped up 3 inches. I get a lot of vibration at idle, but no other symptoms. So the question: do I just replace the passenger now with an H3, replace both now with H3's, or wait til the driver's fails, then replace both with H3's?