Bumps Thuds and Vibrations How to Diagnose Bad Car Engine Mounts

Do you feel a sudden thud when you shift your vehicle into drive? That's what we're gonna talk about in this video. All right. So you shift your vehicle into gear, and you feel a sudden jerk, and you put it in reverse, and the same thing, the whole vehicle kind of moves a little bit. Here's an engine mount right here located in the front of the engine. It's on the passenger side on this vehicle. This mount is supporting all the weight of the engine right here. And there's also a transmission mount on this vehicle.

And other vehicles have other types of mounts like this. Sometimes they call this a dog bone mount. Now the engine is not supported by this mount. This just prevents the engine from rocking back and forth. So if you saw a lot of movement in the engine rocking back and forth, that could be your problem. And if you have a vehicle with a larger engine, there may be no supports up top and the mounts are just down below. Here's another dog bone transmission mount. So what this mount does is it doesn't support any of the weight of the transmission or the engine. It just prevents it from rocking back and forth.

What you want to do is put the parking brake and push on the brake pedal really hard with your left foot. You're gonna shift into reverse and then just accelerate while your friend is watching the engine from a safe distance. Then you can shift it into drag and do the same thing. And if the engine moves significantly then you know you have an engine mount or a transmission mount problem. What you want to look at when you're checking out these mounts is see if there's any large cracks, if there's any dry rot, major cracks in this.

If you see there's a little bit of dry rot in there but a lot of times you'll see small cracks that are in the...it's in the coating that this mount was coated in from the factory and that's not a big deal. This is starting to dry rot. I don't see any major cracks yet. But also if you've had an oil leak where it's leaking into the rubber, it's been compromised, you want to make sure you fix the oil leak before you just put a new mount in because that's not gonna do good. You're just gonna ruin the new mount. If you wanted to check out one of these dog bone mounts with a pry bar, you can just get in between the frame and the mount and just pry them out.

And if you saw a movement like this or even in between engine and transmission, that mount would be excessive. We actually loosened up this bolt just to show how much movement you could end up with. So you'll have a little bit of movement when it's tight, but if it's broken, you'll see a major cracking in there, and then you'll know that mount has to be replaced. So with this bolt actually tightened back up and I pry on this, you can actually see some of the dry rot. So this mount is gonna have to be replaced soon anyway. It's not as bad as we made it out to be but it's definitely on the road to need replacement.

You may have a mount like this. In this case, you would want to pry in the direction that the mount is supporting, so up and down, and check for cracking in there. And some mounts actually have hydraulic fluid in them. And if you see any mounts leaking, it's time to change those. This is another dog bone style mount that you would pry in the direction that it's supporting. And then this style mount, this is more like a transmission style mount. It just supports and we would want to pry in the direction that it supports and take a look at any of the rubber cracking if you can see it.

Another symptom you may experience with worn engine mounts or transmission mounts is when you come to a stop while you're sitting there in gear, you may feel excessive vibrations in the cab, you may feel it in the steering wheel or even in the floorboards. That's because the rubber on the engine mounts isn't doing its job. It's not canceling out the vibrations from the engine and they need to be replaced. Now, if your engine mounts are dry-rotted and old, chances are you're just better off replacing all of them. I hope you enjoyed this video. If it helped you out, please subscribe to our channel and make sure you ring the bell, turn on all notifications so you don't miss any of our videos.

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