udelslayer

2009 90k, FWD DIY maintentance, no modifications (but it the wife's car LOL)

So, apparently, this shares the same mount platform with the CR-V, a vehicle with much less power. I took a quick look but didnt find any threads relating to issues although there are many other model threads with details about mount replacements.

I recently had to resort to a mechanic to replace my front axles for the first time and freaking out about the symptoms since I dont work on this car other than the basics to keep it reliable. I was having vibration on acceleration at 50-55. Did a balance, alignment, rotation, and tried tracking it down to the tires since two have plugs. The problem seemed to have always been there, but got incredibly worse a week after I did a brake job. I was worried about cheapy rotor balances, but the vibration only happens on moderate acceleration. Flooring it, coasting and braking show no signs. I really dont like how they've tried to capture a "sports car" suspension in something this heavy. Oh well.

Anyway, since I couldnt do the work at the time, $600 later, I had new axles and it drove like a dream again. I am sure the axles did have issues considering the other threads entailing the weak inner CV cups for many of their cars. I dont think these units are "specail" for the RDX.

So a week later in review, my wife says there is still vibration at slight pedal at 55ish. I drive it and sho-nufff - an annoying almost out of balance tire feeling. I rotate ALL the tires to different location, check lug torques, carefully examine ball joints, and tire pressure. Both plugged tires are on the back now. She is convinced its a tire problem. I am not. As described in other threads, it feels like a torque converter lock, plug performance, or the engine is getting ready to puke. I do the TPMS reset (dont know if that even works).....the symptom was driving me C R A Z Y. I am good at troubleshooting this stuff.

Then I run into some threads about several Acura and larger Honda's with V6's needing their mounts replaced at 55k, 70k, 100k and some even earlier. WOW. What the duck? Are you guys having to replace them on the cars and which ones are failing. I had her do some shifting while I observed under the hood, and I could see the motor rock at least an inch in either direction. It seemed too much. On start, I can now identify a rattle I had been tracking. It simulates a rough running engine at idle and cruise.

This problem can cause you to run down the wrong rabbit hole. I cant find a decent replacement procedure or video.

Ebay sells a 2 mount kit. Anyone used it? Nobody makes performance mounts? I'd rather go stronger and upgrade instead of use this boob-job-silicone level low hardness crap Honda is using. Why cant it be a normal mount I can fill with Window Weld. Which ones fail first?

Anyone have experiences or pics, please post'em up. I dont know if I should get all three or if there is a specific culprit.

Thanks
Jeremy

udelslayer

wow nothing?

an unpopular car....

no wonder I dont enjoy driving it.

Tomtwtwtw

Unpopular car or uncommon problem? Plenty of guys on here well over 100k miles with no motor mount issues, which is probably why no one is posting about their experience replacing them.

For what it's worth, have you tested to see if the vibration is the same in each gear? If not, do that and see what happens. If the vibration remains constant in 3rd, 4th and 5th gears at a steady 55, it's definitely not your mounts. If the vibration changes based on engine speed, then maybe you're on to something.

bluecarbonfiber

if the tire shredded on the inside it can cause vibration the only the tpms sensor cares about is tire pressure so you can still hold pressure with a split on the inside of the tire it just takes a while to leak out if it ever does.. I had an issue of vibration on one of my tires and I kept going back for the rebalance till I got new tires and they realized I split the inside of my tire (food for thought)

udelslayer

I think its a more common problem than people realize. If you look at the mount layout, there is pretty much a single dogbone holding the engine from rocking. On cold start, I can see the motor vibrate fwd-bk (like most motors) in cadence with a momentary rapping sound thats is not internal. It moves like a plucked rubber band. Going from p-d-p-r with the foot on the brake, shows the top of the motor pitch back or forward.

There are a lot of threads about torn and broken mounts in the MDX and others. While its different, its not. I can't believe its the transmission (and I know they have issues). I have tried different gears, same feeling. And something I just realized is that this mount that would be the weakest is directly above the turbo. I think many people assume its the way it rides because of the stiff suspension.

WRXs have this issue with CV boots too close to the heat.

At the right load and rpm, the harmonics are going to be felt. They've geared them for max economy and that almost seems to feel like a motor straining which can cause harmonic feels. I've always felt the gear and running rpm was too low.

Tomtwtwtw

Here's the thing though - if you get the same vibration at the same road speed, independent of the engine speed (i.e. same in all gears), then I can't see how it would be the mounts. And to your point about start up, the engine is going to move. The mounts aren't supposed to hold the engine 100% rigid - they allow some movement and their primary job is to isolate the cabin from the NVH the engine produces. If you've ever driven a car with 100% solid mounts, you know that if the engine isn't allowed a little room to wiggle, then the whole car shakes. Great for racing, bad for comfort. Other guys that have had a persistent vibration at certain road speeds seem to have had some success getting all wheels road-force balanced.

As a reference, some other signs that point to worn mounts in FWD cars are a grinding sound under load (can happen in either D, R or both - points to excessive engine tilt putting strain on the CV joints), and/or a loud noise/excessive thunk when first shifting into D or R - also due to excessive engine movement. That is specific to the mount that restricts front/rear movement. Other mounts that go bad can introduce extra NVH into the cabin, but it should be related to engine speed, not road speed.

With all that said, if it does sound like your engine is moving too much and you want to replace that upper mount, the procedure is pretty simple.

1. Support the engine from underneath the car (but do not use the oil pan!)
2. Remove anything that may block access to the mount...haven't looked under my hood recently but this may or may not include the intercooler and/or intake piping. If it's on the passenger side you're probably already good to go.
3. Once engine is supported and the path to the mount is clear, just remove and replace.

TheWrench116

iTrader: (1)

no issues with mine and im straining the factory parts quit a bit more then you. 118,000+miles try looking at the prop shaft as it can throw a weight.

udelslayer

There is a noticeable thunk shifting p-d-p-r, but I dont DD the car, so I may be hypersensitive. I took it for another test in both D and S mode since the RPM/gear will differ by a few hundred and feel the pulsation at 55-57mph, so speed dependent and under acceleration only. I still think the rear upper mount may be worn. Perhaps the axles my shop used are crap. I am going to start with the mount and then go from there. If I gun it, I can't sense any wobble. I feel it under "regular" acceleration as I approach nearly 60mph. If I release the pedal at 70 and let it naturally coast to 50, there is no problem.

Tomtwtwtw

I would lean more toward axles, also because that definitely has been a problem different owners have experienced. Either way, please so share your results. Definitely curious what the culprit is here.

udelslayer

I replaced the pitch mount 2 weeks ago because I had bought one. That wasnt the problem as in the other threads I've been talking about axle cups. What I am going to do is fill the oem mount with window weld and reinstall it. I was surprised that all of the power is relying on that pitch mount. With the mount out, I could easily rock the motor by hand. The aftermarket civic ones can be used, but WW is a great option (although they jacked the price way up since I last bought it).

By prop shaft, do you mean the intermediate one that connects the axle? Is that thing supposed to have a donut on it?

udelslayer

FWIW, I filled the oem mount cavities with urethane that seems to have a good elasticity, although I dont know what the hardness is. I wanted to use 3m window weld (metal tube) but the price has gone through the roof! It used to be 10 bux, but I guess something changed because now its close to 30. Lowes was having a sale on a permanently elastic urethane exterior adhesive in a metal tube that seems to have all the properties of window weld....for a magic 8 dollars. I'm not sure if I want to install the mount yet because I know it will put some NVH in the cabin and its the wife's car but have you ever seen how much the engine moves? Its literally a rubber band holding what looks like 3 inches of travel. Thats got to make shifting less crisp. Does anyone know if the awd vs the fwd pitch mounts are different?

TheWrench116

iTrader: (1)

i was thinking of doing solids until ken got some poly mounts just seems like they are not available yet... last i checked anyway.

udelslayer

They actually are. The part is cross listed as a Civic SI mount with the K-series in it. Those aftermarket solutions should work. This is why it baffles me that I cant find upgraded axles that can withstand FWD forces because imho, this is one heavy Honda. I just happened to have the spare and it good shape so why not experiment? It did wonders on my Sentra SpecV but I also did the balance shaft removal mod so I got lots of buzz in the cabin. I recently put a Cobb mount on my buddy's MS3, which has the same kind of pitch mount configuration as the RDX and there is quite a bit of vibration trasmission into the cabin. Its not that I can't stand a little NVH when I know its not a problem, but vibrations have a tendency to accelerate wear on other things. I just feel that there should be a true hydraulic damper system for the pitch to ensure that hard shifts are cushioned for the transmission. After looking at the Factory Manual, I can't believe this thing even works. I bet its got more parts than the motor.