Vibrations after Replacing Front Mount - Replace All Mounts?
 

I recently replaced my front motor mount on my 96 Accord. When I first get the car going it feels a lot smoother, then after awhile when I come to a stop I start to feel vibrations from the engine in the cabin again. It feels better, but they are still there.

I checked the other 2 mounts on the side of the engine and they look ok. The rubber for the mount on the passenger side is intact but it does look a bit old.

The back one... unsure of how to really check it but I noticed steering link solenoid looks like it's broken. Since this controls the idle with a vacuum, could this be the cause?

Should I replace the other mounts too?

slide under the car and grab the oil pan and try to move it front to back if it moves the rear mount is bad

however make sure to jack the engine up slightly at the oil pan with a wooden block in between to avoid damaging then pan so the front mount is level before you tight the through bolt

I was able to spot damaged rear mount from pax side w/ air inlet duct removed.

I had wife put car in R & D w/ ebrake and foot brake set. Small throttle inputs of 1500-2000 rpm will cause excessive engine rotation, particularly in R. I was able to clearly see torn mount rubber.

DIY replacement is a challenge as car must be elevated (ramps I recollect). Several bolts must be released from underneath to enable mount removal. Check DIY forum for posts.

Low idle rpm caused by dirty, blocked IACV will also cause significant vibration. Clean IACV movement, IACV inlet/outlet, throttle plate and bore w/ throttle body cleaner.

good luck

I read on here that aftermarket mounts are stiffer than OEM. Could that be the issue?

Maybe I'm just dreaming I won't need to replace that back mount.

I haven't read of any aftermarket front mounts as causing problems. These are stiff rubber w/ a spoke arrangement to add some flexibility. Aftermarket are same arrangement as OEM.

However, I have read of aftermarket rear mounts causing problems due to stiffness.

good luck

Is there vacuum to the mount when the engine is idling (~700rpm)?

On 4-cyl automatic-trans only, the rear mount is vacuum-operated. Not the front one. It goes into it's "soft" mode when idling in-gear only.

Check out that one...
1. Find the solenoid (#9) on the vacuum line for that mount.
2. Warm up the engine.
3. Get a helper to shift into DRIVE, don't touch the gas pedal, & HOLD THE BRAKE.
4. Unplug the electrical connector for that solenoid. That should make the vibration noticeably worse. If there's no difference, then find out what isn't working.

Solenoid failed? Bad wiring to the solenoid?
No vacuum in that vacuum line? Disconnected vacuum hose?
Maybe the mount itself doesn't hold vacuum?

The RPMs are relatively high at a stop. Usually around 900rpm or just under 1000rpm. I played with idler screw which helped a little bit.

Seems that way to me. I believe part #28 in the diagram is broken from what I can tell when I get under the car and look at the mount. It's a connector to the arm part of the mount.

Set the base idle and let the IACV do its job:

Setting Base Idle speed

If the idle's too high then even a perfect rear mount won't work right.

I noticed it is a lot worse when the A/C is on. I'll try setting the base idle speed.

If the mount doesn't hold vacuum, then something's wrong anyway.

But go through the process of setting the base idle just in case that's the whole problem.

I just replaced my front motor mount ... still some vibration. I tried R&D with the ebrake on and wheels chocked ... not really any excessive engine movement. Just a good vibration when the engine is in gear.

For the life of me I can't see behind the engine to figure out which of the 3-4 solenoids might be connected to the motor mount. These engines have a lot of clutter and the spacing is really tight, especially in the rear. If anyone out there has already done this on an F22B1 engine and can give me some cheating hints, they will be much appreciated. Otherwise I'll have to get the car back up on ramps tomorrow to give it another try.

Thanks. John

PS: Here's the one I replaced ...

https://www.hondaaccordforum.com/for...1&d=1411247850

The solenoid for the engine mount is on the drivers side kind of high up....my 97 isn't home right now or I would take a pic.

Okay thanks, that may be enough. I have a CD7 service manual which has diagrams displaying every solenoid in the engine except for that one (go figure) ... but it does have the troubleshooting steps for the rear engine mount, so I should have enough now to figure out if there is an issue.

Thanks. John

PS: You don't know where I can get a CD5 service manual, do you?

If the pdf manual you have is the same as mine look in section 5, page 28. I have the actual book for a 1995 (thanks to PA) and it is in the same section.

shoot -- I missed that one. Thanks :)

@jkowtko - The pic of the old front mount looked just like mine! :)

Just checked the car --

* with the engine at low idle, when I unplugged the solenoid. No change in engine vibration -- but I could hear the "exhale" of the diaphram on the rear mount. Plug it back in and and I could hear the vacuum suck up again. I did this repatedly. So, the solenoid seems to be functioning okay, and it sounded like the diaphram on the mount was doing something.

* I then shifted in Reverse and revved the engine. I could see engine rotate forward and the rear plate of engine on top of the mount raise up maybe 3/8" ... I assume this is too much movement and the mount is broken?

It's really hard to see back there, but there is a small viewing window from the drivers side of the car, looking down below the intake manifold. Not much space to see, but I could see the engine lifting relative to the mount.

I'll reconfirm again later before I buy the mount ... but first a little research to see if there are any aftermarket mounts that work well (OEM is pretty expensive).

I've never been able to detect a change in vibration level when vacuum mount is actuated.

Movement of 3/8" should be OK. Try looking from Pax side w/ the air intake duct removed and a good light. Mount is easily viewed and any loose pieces or excess movement observed.

good luck

*** Update ***

I removed the air intake today to get a better look. turns out the rubber is stretching a bit and has micro-tears in it, but still holding on. And the vacuum diaphram works. But the metal linkage is broken -- snapped at the elbow. I didn't expect that part of the mount to fail first.

I'll be looking for a new mount now ...

How long did it take you to take the intake manifold off and how hard was it? Also did you use hand tools or have an air compressor with air tools?

I didn't remove the manifold ... only the air intake filter box and hose -- the black plastic parts leading up to the throttle body.

That allows for enough access? Can you share pictures?

Removing the air intake duct only allows a VIEW of the rear motor mount for inspection and determination of damage. It does not allow enough access for replacement.

Replacement requires working from underneath vehicle to access rear mount lower bolts and connection to transmission. Intake manifold is not removed. I would estimate 3-5 hrs of steady work by DIY'r.

Check youtube for videos. I remember a good one, but I looked and could not locate.

Following may be slightly helpful.


good luck

That's the video I found as well .. covers it well .. and makes it look like a 30 minute job!

You will find that space underneath is adequate to remove the mount, but it is awkward and tedious work laying on your back. Most of the time is consumed w/ the underneath work.

I also found the vacuum line to the mount would not release; difficult to reach and stuck, so I had to cut flush to remove the mount. The flush nipple on the mount is fragile also!

good luck

One question -- do the front and rear mounts actually support and of the the weight of the engine, or are they just torsional dampers?

When I replaced the front mount I didn't really have to support the engine ... I did push up on the engine maybe 1/8" just to make it easier to slide the main mount bolt in place, but that really wasn't necessary.

I'm thinking the rear is the same -- some small amount of weight on the mount, on the order of 1/8" compression, but otherwise not holding up the engine. Am I wrong on this?

Thanks. John

Agree there is little/no weight on rear mount.

good luck

That channel got terminated and they must have just re-uploaded all their old videos on a new one.

From the video it looks like he has the car high and on 4 jackstands.

You may need to lift engine slightly to align mount w/ engine bracket. I remember using jack on mine in this fashion.

good luck

This rear motor mount looks almost impossible with basic hand tools. Idk, is it worth a shot?

I've replaced rear motor mount twice on my 94EX. Once when failure was obvious and a 2nd time chasing vibration problem. Job is not as much work as timing belt, but is a challenge. A good bit of work lying on your back, which I hate.

good luck