2009 lexus rx350....
Hi everyone, i was curious to know...how do you tell or test to see if an engine or transmission mount goes bad?
From what i can tell, there is a:
-mount in the bottom, front (next to the rad), which has air tubes going into it? this is an engine mount, correct?
-there is the one at the top, passanger side, next to oil filler cap (engine mount)?
-there is one at the rear, bottom of engine (engine mount)?
- i think there are also one on each side, behind the front wheels...are these engine mounts or tranny mounts?
the one at bottom front and the ones behind the front tires, have a rubber, kinda cap or cover, how do you test or check if these are bad?
I looked at the upper, passanger one and the one at the bottom rear and those seem okay?

What are some symptoms when they go bad? is it mostly noise (clunking), or can it affect performance?
thanks
fab

 

Yes those are the engine mounts.

Symptoms of bad ones:
Engine shuttering when accelerating felt while driving
Visual leakage
Excessive movement seen when engine is running especially noticeable when accelerating (someone pressing the gas pedal

They are not expensive not hard to change out, not uncommon for them to wear with time/miles as are so rubber parts on the suspension

 

Two side ones are hydraulic and can leak, driver side is trans mount, and right side is side engine mount. Front one is vacuum-actuated to cancel out vibrations at idle, and also has hydraulic fluid it in well. The rear one is a stopper and the top one is the dogbone. I find that when the dogbone fails, it usually introduces a lot of extra wear onto the other mounts. I had a few go bad and they each had different symptoms. You can look under the rubber cap to see if the mount is rusted, or look underneath it to see if the diaphragm is ripped.


Left (Tranny): Rough shifts and clunk when going into gear
Right (Engine): Lots of vibrating in drive, would ease up when going into neutral
Top: Noticeable lurch when taking off, that's probably the motion that takes out the other mounts

 

Thanks for the reply gang. I noticed that the tranny one is rusted good under the rubber cover. I haven't looked at the engine (pass side or lower front) one yet. There doesn't seem to be any fluid loss on any of them.

MATTRX.... For the tranny, not getting any hard shifts or clunking. For the engine ones, at highway speeds it's still smooth. I find i feel a bit more vibrations when just idling at a light, lets say. This week, i put my phone camera on the side of the engine. i recorded the engine at idle, then with one foot on brake pedal, i put in in D, and applied gas...then in R and did the same (back and forth). I then looked at the footage and there was no major jerking on the engine,, seemed pretty stable.

Our roads get salted in winter time and i park in a heated garage...i think does a number on the parts of the car and get really rusted. Is it possible for the mounts to get rusted to heck, but still be okay?

Matt....i just saw that you have a 2008 rx350 with quite some milage on it!! i see you're from Ontario, so i guess you have some rust as well on yours? have you ever changed out your mounts yet?? (btw..i'm at 255 000km!)
thanks
fab

 

Oil is the greatest enemy of engine mounts then age. I personally think the active mount is a total waste it does little to nothing, as a test I disabled it on my ES and couldn't tell the difference.

 

The body of my RX and the frame are surprisingly rust-free compared to some of the other RXs I have seen driving around. I did have some issues in specific areas like that trans mount (also mount seized to trans casing so I had to whack it out), front control arm bolts seizing into the collar, rear control arm bolts seizing into the collar and some of the doors developed some rust so I replaced all four of them with some I found off an RX330 at the junkyard. I'd say that's nothing unusual for here though, just business as usual with Canadian cars. The rear subframe on the RX is getting a little crusty but I can always replace that or take it off and repaint it. I'm just glad the frame itself is very clean. My Highlander has held up well too, but I need to touch up a few areas soon on it incl the rear subframe (no holes, just more rust than I'd like). These things are tough as hell!

As for the mounts, yep! My driver/trans mount completely rotted out! The diaphragm was still okay, but the metal portion was so far gone that you could feel the trans moving. I replaced all the mounts on my RX except for the front vacuum one. I also saw something worse happen on a friend's 2006 RX400h, the mount was completely gone and the trans was unsupported. I have a post about it on my 2008 RX350 Project thread and a separate thread of the 400h one with 380,000km! On my 02 Highlander with 300,000 (Same mounts as an RX), the diaphragm failed on mine and all the oil leaked out, but it was still physically together.

https://www.clublexus.com/forums/rx-...have-seen.html

 

i just replaced the dog bone, left and right engine mounts and the left and right lower control arms It took 3.5hrs. I will replace the front mount this wk. With the car on a hoist letting the front wheels hang , the LCA bushes were badly ripped. The dog bone bush was also ripped. The engine mounts showed no obvious damage. Replacing LCAs and mounts at the same time is not a lot of extra work

 

Mattrx....i think mine are starting to get there, but as i said, no visible leaking. When you say you can see or feel the trans moving...do you mean like hard shifts? Not shifting properly? Do you hear clunking, especially over bumps? I saw your pics...it seems like the metal under the rubber boot is completely gone! But it didn't seem to be leaking? Couldn't you have kept it on, or was it too far gone? I really don't think our crappy QC roads help out either!

 

My RX one didn't leak, and actually it felt stiffer and better than the one on my Highlander that lost all the oil instead of rusting it. No clunking over bumps, but you would feel a springy/lurch feel when you shifted from park into drive, especially when the engine was cold. From 1st to 2nd you would feel it in the "seat of the pants", 3-4 too to an extent but not as much. It did shift properly though but you could definitely tell something was a little off.

I probably could have kept going, but it definitely didn't feel great and I was worried about introducing wear to the other mounts by having it be bad.

 

Mattrx, okay thanks. I don't really feel these things on my car. No hard clunks or hard shifts. I guess it's still good?

one reason i still i still kept the car is that it has no rust on the body, and everything inside works.
fab

 

It's probably still good then! You would probably notice something was off if it looked like mine.

 

Good info here

 

09rx....
funny enough, i watched that video earlier tonight. Pretty good.

 

I watched that last night! Good to see some more fellow CCN viewers hahaha!

 

Mattrx, forgot to ask...when you changed the mounts, did you go with oem or aftermarket?