Hey, I haven't really seen many post of motor mounts for my car here. I recently started hearing a clunking noise when gassing from a stop. I also put the car in drive while holding down the brake and tapped the gas pedal a couple times and was able to duplicate the noise. Makes me feel like it's the front engine mount. I'll try the same thing later for reverse to make sure it's not both mounts.

Car only has 105K miles.. I don't have a lot of experience with mounts and when they typically need to be replaced but I was a bit surprised. Anyone here replaced their engine mounts yet? What brand did you guys go with or should I stick with OEM? Is this an extensive job in terms of labor?

 

You need to make sure you diagnose this correctly. The front mount is 776$, the rear mount is 470$. The side mount is the cheapest at 210$. Due to. the VCM feature of the RDX, these mounts have to be more complicated and robust. These same mounts on my 2012 TL are all ~150$ apiece or less. These are online prices. A lot of folks have disabled their VCM for this and other engine wear/life reasons. The TL does not have VCM.

I have never diagnosed a broken motor mount, hopefully someone on the forum will chime in and tell you a way to do it.

 

Holy crap!! I was not expecting for it to be that expensive! I can't really see the front mount that clearly since the radiator/fan is in the way so there's no visual inspection on my part. Also there appears to be some sort of a cover on the mount as well so I can't tell if there's any cracking or anything.

I've watched a couple videos of people putting the car in drive and while holding down the brake pedal, tap the gas so the engine will rock up and down and if you hear a clicking/clunking noise.. it's the front mount. Putting it in reverse and doing the same for the rear mount. I don't have an issue there thank God.

Unfortunately this is what I'm hearing for the front. But I will definitely be getting someone to take a look into it who's way more knowledgeable than me.

Curious, did you check these prices just now? Or have you had to get this done on the RDX before?

 

After I read your post, I went to "yourwholesaleacuraparts.com" which is where I buy a lot of my OEM parts from. The MSRP for the front mount is 1155$ and the rear is 693$ which is probably close to what a dealer would charge you for these parts if they do the work. While I drive the 2012 TL, my wife drives a 2017 RDX. So I follow this forum also to see what's happening to these cars as they age. Needless to say, that price lookup scared the crap out of me.

 

Please explain a connection between VCM and engine mounts. I see none.

 

VCM (which I believe stands for "variable cylinder management") shuts down 3 of the 6 cylinders of the engine while cruising at light load to conserve fuel. With these cylinders shut down (not firing), the forces in the engine go out of balance to some degree. So the engine will shake/vibrate more. The fancy motor mounts are designed to absorb this vibration so you don't feel it. It works. I drive my wife's 2017 RDX on long trips and I can't tell when the VCM is engaged. Her RDX also gets ~2 MPG better fuel economy on these trips than my TL even though the RDX has the aerodynamics of a brick compared to the TL. Both have the same engine and 6 speed auto transmission.

Do a search on VCM on this forum and you will see more detail and the pro's and con's of the system. Many folks have given up the better fuel milage and de-activated the system.

 

The VCM cuts off cylinders and on again depending on your driving situation. The motors tend to move a lot as a result, hence the need for much stronger mounts.

 

It is correct that VCM deactivates 3 out of 6 cylinders, but during steady cruising only. Most engine vibration happens during start, when internal unbalanced components (pistons and connecting rods, … not shafts, as these are balanced by design) started to move suddenly. Or, if there is a problem with engine, when few cylinders are not firing up. But this is only at idle. Once you load up engine with higher rpm, shaking/vibration goes away, thus no additional vibration happens during VCM switching on-off, as this transition imperceptible by engine running under load and at rpm above idle.