Cracked motor mount

[marpel]

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

[Grit_dog]

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]

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]

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]

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]

naughty, naughty Marve you let us mammy jammy for two pages before you told us the rest of the story.

[Perrysburg_Dodg]

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]

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]

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]

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]

Seems common.

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

[mkirsch]

There are several videos on youtube showing the problem and/or detailing the replacement process of the driver's side engine mount, so apparently it's a common issue.

[Dave_H_M]

If i read the OP post correctly, the "mechanic" said the mount was cracked.

i would have done like Scott suggested, or have the mechanic show me the crack.

Lets get it on. :W

[memtb]

wilber1 wrote:
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.

I had the same experiences many years ago, with the same side motor mount....only it was on a Ford Torino GT 390. The left side mount gets a lot of “exercise” during hard acceleration and/or during towing a heavy load.

It’s not hard to check....locate the mount, have someone accelerate the motor, while in gear with brake on! The motor will torque to the right (passenger side).....if the mount is bad, you will be able to see it separate!

[SidecarFlip]

Just looking at one when the engine isn't running (torquing), it's impossible to tell if the vulcanized biscuit has separated from the metal mount. It has to be running and revved up while observing the mounts. Like I said, not expensive or a big deal to replace, unlike the new GM steering boxes are (6 hours labor and 450 bucks a throw), if you can get one that is.

Never heard one 'thump'. Have heard cooling fans hit the radiator shroud before however.

Like I said, replacement is easy. Jack up the engine enough to remove the bolts and replace.