growrx300

I need to replace all my motor mounts. I believe there are three, two on top of the engine and one lower. Someone correct me if this is not correct. Getting the upper ones replaced was fine but no one locally can find the lower mount with the vacuum port. Any suggestions?

carguy07

I think this is what you are looking for.

lexina

There are 3 engine mounts. Passenger side mount, front mount, and rear mount.

growrx300

Thanx for the responses. That was a big help.

kalali

Are these "active" engine mounts? What are all those hoses for?

growrx300

I found a mount on eBay that is called "front motor mount hydraulic w/ vacuum port". I think it is what I need.

salimshah

Mount near the front (radiator) is the active mount (it produces counter kick to even out the shakes). I think that is why Lexus uses 3 point mounting system ... with 4 they would be fighting against another tether point.

There is a 4 connection point (no weight transfer is involved) this ensures all the torque is transferred to the wheel and the engine does not twist. Top of the engine near the passenger. This mount is usually the first one to go.


Salim

growrx300

Thanx for your help!

Brcobrem

Hi,
Just out of academic curiosity, anyone know why there's a vacuum line and vacuum sensor running to a motor mount?
Thanks . . .

salimshah

Vacuum plumbing diagram is affixed under the hood. Not sure if it goes to the mount though.
Salim

Lexmus

The front mount is an active mount. The others are passive.

Have you changed any of your mounts? I changed the dogbone torque mount recently, and also plan to do the transmission mount as it is flattened.

Brcobrem

I just added "Active Mount" to my vocabulary. Thank you salimshah and Lexmus for the helpful replies.

Now knowing what to look for, I found a useful (imho) link on this: http://www.brakeandfrontend.com/tech...-trans-mounts/

Note the part about vibration at idle when these fail. Never experienced this myself, but seems that this vibration could be wrongly diagnosed as some other engine problem. Good to know for future.

Regards . . .

Brcobrem

Hi salimshah,

For other members and posterity (as you suggested above) here's a pic of the 2000 RX300 USA vacuum lines from the sticker/label on top of the radiator frame:



Thanks again for your help.
Regards . . .

pieceofbread

Hi I have a 2000 lexus rx300 and I think the motor mounts are going bad on it. So the only three motor mounts the 2000 lexus rx300 are the top mount, rear mount(the one under the oil filter) and the strut looking mount? (the one thats near the o2 sensor)

salimshah

Please verify that your assumption is correct by confirming the mounts are weak or broken. In extreme cases one can noticeably see the engine shift position. Also engine and transmission are connected at bell housing. The transmission also has mounts. Those mounts can go bad as well.

There are 3 mounts ... all below the engine. One below oil filter is "active" mount which counteracts the engine vibration and the other 2 are passive. There is a dog-bone support at the top of the engine which is a brace to counter act the torque developed by engine under power.

Mechanics along with visual also use long pry bars to forcibly shift the engine/transmission to see if the mounts are compromised.

I have never priced the mounts. The active mount maybe fairly expensive.

Salim