[filius]

I appreciate you taking the time to post this since I am about to start this project myself.

I was wondering, why did you remove the "upper and lower air intakes, the battery, loosened the bracket that anchors the air-filter box, and removed the top "banjo" mount by removing the two bolts that pass through the rubber bushings at the head and tail of the banjo"? Was this to allow the engine to move around?

 

[filius]

I changed all four motor mounts on my 2004 Sienna CE FWD. It was my first time doing this. I thought I would share my experience in case it’s helpful.

As the OP says, you should jack up the car and put it on jack stands. Then place the jack under the engine with a block of wood to protect the engine, in a place that can support its weight. Jack up the engine just enough to support it while you’re removing the bolts.

I started with the lower rear mount on the driver’s side. I took off the wheel and removed a plastic shield from the wheel well (held on by two 10mm bolts) that was partly in the way so I could get a ratchet on the top bolt of the mount. The top bolt came off using a cheater bar, without too much trouble (as did the bolts on all the mounts). You have to remove round plastic plugs to reach two of the bottom bolts which go through the frame. The third bottom bolt is not covered.

Getting the bolts off was the easy part. The problem was raising the engine enough so that the top and bottom bolts of the motor mount would clear the frame and the engine, so I could get it out. I was afraid to raise the engine too high for fear of stretching the wires and hoses that are attached to the engine.

Eventually I decided to remove the windshield wipers, wiper motor and cowl assembly (not as hard as it seems if you have diagrams), to provide more clearance to raise the engine. In the end, I realized that it might have helped if I had remove the top engine motor mount (passenger side) as well, which was making it hard to raise the engine since it was holding the engine in place. So, my suggestion is to remove the top motor mount first (as noted in the OP). It comes off pretty easily with just two bolts holding it in.

Anyway, after raising the engine a little at a time and fiddling around with the mount, eventually I got it clear. Surprisingly, the new mount went in more easily than the old one came out. It threaded the nuts on partially but didn’t tighten them, so that it wouldn’t prevent the engine from rising when I tried to remove the other mounts.

Next I did the lower rear mount on the passenger side. Basically the same procedure, but this one came out more easily – once I removed the top motor mount, which is directly above it. If you don’t remove the top mount, then when you jack up the engine the whole car starts to rise. I learned this from experience.

Finally I did the single front motor mount. The top bolt was not hard to reach using a series of extensions totaling about 15 inches in length. The bottom ones are easy. I did not remove the battery or air intake as the OP says to do. But one thing that was in the way, preventing me from removing the mount, was the radiator hose. Eventually I was able to wrestle it out without removing the hose; but I couldn’t get the new mount in with the hose in the way. So I disconnected the hose, which of course drained the radiator. At this point I said what the heck, I might as well drain and replace the engine coolant while I’m at it, which I did.

With the radiator hose disconnected, I was able to get the new mount in fairly easily. I did have to remove the nuts from the lower rear driver’s side mount (which I had screwed on loosely), to allow the engine to rise enough to clear the bolts on the front mount.

Last of all I installed the new top mount, which went in easily.

In summary, it’s a fairly straightforward job and the bolts are not that difficult to access or remove, which was my biggest concern going in. The hardest part is making enough space to get the mounts in and out.