2012 Sierra, 6.2, tow package.Recently completed a trip to/from BC/Denver Co, pulling a fairly small (4000 lbs loaded) travel trailer. Have done this trip a few times in the past. Usually under 65mph max and no rough driving. Am a conservative driver and don't mistreat vehicle (like race off the line etc.).Upon return, visited my local mechanic for oil change. Part of that service is tire rotation and inspection of various components.Mechanic reports that the left motor mount is cracked and needs replacing. Advises that this issue is not completely uncommon and usually related to engine torque (which is why it is common on left side).I am on my fourth truck and have never experienced this issue before, however, this is the first truck that I have used to tow a trailer of this weight (last one only towed a 2000 lb light), although this truck is rated for 10,400 lbs so this trailer is quite light, comparatively.Anyone familiar with this issue, who can comment on whether it is related to trailer towing or just day in/day out torque from this sized engine? As stated, I am very conservative and have never "pushed" this vehicle. If it is a direct result of torque, wondering what I can possibly do to mitigate future potential issues.Thanks,Marv

One thing, not a difficult replacement and the part isn't that expensive either. Never broken a motor mount and I have a diesel.

I would crawl under there and look for myself.

I would get a second opinion for sure. If it does need replacing, thank your local mechanic and stay with the service. If it does not... get under, take a picture of it up close with a digital camera, and see what it looks like the next time you are about to go to the mechanic again.

I have a 66 Chrysler 300 with a 440 TNT. It liked to eat LH mounts so now I have a chain on it so it can only flex so far. They didn't crack, the rubber separated from the metal.

GM years ago redesigned motor mounts to include a built in stop, to keep it from being completely lifted up off the frame. Chris

Cracked motor mount | Good Sam Community

Grit_dog
Navigator
Jul 29, 2018
Yes it's entirely possible it's cracked. No it's not common. 30-40 years ago, very common.
Get it replaced. Shouldn't be a big deal unless the mfgs have made engine mounts difficult to remove. Don't know becasue I actually haven't had a bed engine mount in any vehicle from the 90s forward.
marpel
Explorer
Jul 29, 2018
Dave H M,

Not sure what you mean about me waiting to tell the full story. Initially (and still), I was not suggesting I was questioning my mechanic's assessment. I was posting the info I did just to give a basic background to the reader. My purpose of the post was to seek input on the possible cause of the damage and whether it could be related to towing a trailer or how common the issue was.

The quality of my mechanic was/is not relevant to the story, at least in my opinion.

And, as it seems, some have experienced cracked mounts more than a single time in the past, although no one has connected it to the rigours of towing a trailer.

Marv
Farmboy666
Explorer
Jul 29, 2018
Artum Snowbird wrote:
I would get a second opinion for sure. If it does need replacing, thank your local mechanic and stay with the service. If it does not... get under, take a picture of it up close with a digital camera, and see what it looks like the next time you are about to go to the mechanic again.

If you feel the need to do all that your dealing with the wrong people. Why would a mechanic lie about a motor mount? Treat people the way you want to be treated with a little trust and your life will be much more pleasant.
Redcatcher70
Explorer
Jul 28, 2018
Perrysburg DB, I had flash backs when I read your post. I owned a '69 Cutlass Supreme S with the 350 ci. and Turbo 350 auto. transmission. It love to break left motor mounts also.... Those were the days!!
Dave_H_M
Explorer II
Jul 28, 2018
naughty, naughty Marve you let us mammy jammy for two pages before you told us the rest of the story.
Perrysburg_Dodg
Explorer
Jul 27, 2018
Back in my hot rodding days every GM I owned had at least 4 engine mounts replaced. From my 1970 Olds Cutlass S, 1976 Chevy Nova to the lowly 1976 Chevy Monza. Back then we would wrap 1/8" steel cable around the left mount and clamp it with a cable clamp. The downside you could twist the left frame rail after a while. The Nova had to have the engine cradle a left rail pulled to bring it back in spec. Could not get the front end aligned tell it was fixed. These were the days....fun times.

Don
marpel
Explorer
Jul 27, 2018
Thanks to everyone for the replies.

Just to be clear, I have complete faith in this mechanic. He's one of the most competent (been in business for over 30 years and is sought after by car-owners from across North America to work on their high-end, and expensive, classic autos) and honest mechanics I have ever met (that, and he showed me the mount). So, I trust what he is telling me. And, the mount is only cracked at this point and not yet separated (he tells me I can still drive it until it is taken in for repair on Monday).

Was just curious whether anyone knew if this is fairly common and if it could be related to towing a trailer.

Thanks again,

Marv
GWolfe
Explorer
Jul 27, 2018
I drove a 2011 Silverado at work that had the 4.8 in it, it's left motor mount broke. When accelerating from a stop there would be a thump, more felt than heard.
falconbrother
Explorer II
Jul 26, 2018
I would just inspect it and when in doubt, replace it. Rockauto.com is your friend. Motor mounts are usually pretty easy to do. From what I see they range in price from $18.55 to just under $100 bucks.
Me_Again
Explorer III
Jul 26, 2018
Seems common.

https://www.youtube.com/watch?v=MbB46KYK7L0