Can you do a motor mount load test with a helper?

http://www.ehow.com/how_5087174_check-engine-mounts.html

 

Thanks for the link! I got some pictures of the mounts and did a test. Pictures below. Video below that.

From what I can see, the rear (and front?) mounts definitely look worn. I don't know how much risk this implies.

From the test, the motor did not seem to move in any weird ways. I watched the mounts tense and compress in drive and reverse; the mounts seemed secure on the frame and the engine seemed to move through the range of motion allowed by the mounts, but it didn't seem unstable. We only went up to about 2k rpm.

My friend is concerned that the engine will move too much and throw things off balance and cause big problems. What kind of risk am I facing? Should I have them replaced? I don't have a lot of time for another DIY project...



Here is the rear mount (nearest the firewall). This one definitely has some wear.

Here's the passenger-side mount that's higher up on the body. It doesn't look bad from the angle I could see.

Here's the front mount (near the radiator) and it looks okay from this angle.

I stuck the camera further down and got this pic of the front mount. Is it supposed to look partly hollow like that? And is that a crack near the top of the round part?

Video of the test:
Motor Mount Testing

 

There is a transmission mount under the air box. I had a vibration that I eventually tracked down to the cracked rubber.

http://www.toyotanation.com/forum/1.../132-9th-gen-corolla-1st-gen-matrix-2003-2008/693921-engine-vibration-idle.html

I don't see the wear you are talking about but that does look like a crack near the weld on the mount. Do you have a better picture?

For reference, this is what my rear mount looks like for comparison.

 

I wouldn't worry about it. There's really no risk of anything happening unless the mount were to completely break (almost never happens) and regardless you're no where near that point.

Save your money and wait until you start to get a noticeable vibration you just can't tolerate anymore.. and even then go ahead and put it off another year or so..

You'll be fine...

 

Looks all good to me.

 

Researching online, some people say driving with "bad" motor mounts is "fine if you don't mind the vibration" and others say "it's dangerous and could damage the transmission and other drivetrain parts." My theory is that people are interpreting "bad" differently.

I'll define two conditions here and then evaluate their severity. Let me know if I'm right.

Definitions

1. Worn - The bushing has been worn and is not damping as intended.
2. Broken - The actual connection between the frame and engine has failed. The metal of the mount has broken or warped such that it doesn't restrain the engine properly and the engine has an unintended range of motion.

Severity

1. Worn mounts will not dampen properly, but neither will they allow the engine to fall out of the frame or put dangerous strain on other drivetrain components. It is essentially safe to drive with worn mounts, but there may be a lot of vibration.
2. Broken mounts need to be fixed. A (partially) detached engine will put strain on other drivetrain components and may allow the engine to move in ways that would damage other systems under the hood.

How's that? Is that a good summary? Can even badly worn mounts put strain on the drivetrain or will that only occur if the mounts are broken?

 

No that summary is pretty good. A mount has to be broken to cause damage. With no breaks in the rubber there isn't enough room to cause damage even if the mount is weak. Once you get cracks however, that changes.

 

Thanks, hardtop. You say breaks in the rubber could cause damage? I was thinking that even without the rubber at all, the metal would keep the engine from doing anything dangerous. What I meant by "worn" was any failure of the rubber without metal failure. Anyway, I can't see from every angle to verify the rubber's integrity, but there must have been some reason the mechanic reported all 3 as being "bad". The only "bad" part I see is the crack in the metal near the weld in my bottom picture.

 

Mechanics are wrong all the time or they could be upselling something not needing.

A mount with breaks in the rubber can move signficantly and stress wiring, axles, and hoses.

Yours doesn't seem to have any of those problems.

I just did a rear mount on a Dodge Caliber. It has 2 large breaks on the sides of the metal sleeve but the mount was still overall intact. The engine had significant movement towards the firewall. New mount was updated by Chrysler (much larger and beefier). Problem solved. The problem with that engine was obvious.

 

Hmm, then I guess I'm not sure what my mechanic meant by the mounts being "bad" but not recommending I replace them. He said I didn't need replacing anytime soon.

Given the fact that I don't feel excessive vibration and my mount test didn't show much movement of the engine, I'm not going to bother replacing them, but I'll keep an eye on them. I just hope revving to 2k rpm was a strong enough mount test.