Replacing Engine Insulators / Motor Mounts (1 Viewer)

[cartercd]

There have been several write-ups that provide bits and pieces of info on the replacement of the engine insulators (aka motor mounts), so I thought I would consolidate into a step-by-step guide. For reference, this was on my 1997 with 1FZ-FE engine. There are actually 3 insulators, 2 at the engine and one at the transfer case. For my ’97 the part numbers were:

• 12371-66030 transfer case mount. Around $120
• 12361-17011 engine mounts. Around $95 each.

My truck at 182,000 miles has led a fairly easy life, yet the driver side engine mount was completely separated and the passenger side was partially separated. This should probably be a PM if you are still running the originals.

Although there are several ways to do this job, my goal was to stress things as little as possible. On to the fun:

1. Remove the intake tube from the throttle body. Wing nut and clamps on the air filter housing side and 10mm bolt on the throttle body side.
2. Remove 2 bolts connecting the engine wiring harness plastic housing to the firewall. This section of wiring tends to be brittle after 20+ years so you want to give it some room to move freely. 12mm bolts.
3. Remove water valve mount to firewall. Be careful as there are rubber bushings that may be brittle and drop down never to be found again. 10mm bolts.
4. Remove passenger side forward exhaust shield to allow better access to the engine mount bolt. 3 x 12mm bolts. Mine came off easily, but some PB blaster ahead of time wouldn’t hurt if you have rust issues.
5. Remove 4 fan bolts. This prevents the fan from lifting up and smacking the shroud. Don’t be tempted to loosen the shroud instead, as the battery box and tranny cooler lines really make it difficult to get this seated back correctly. Ask me how I know. 12mm nuts.
6. Check your electrical cables from engine to battery and any other electrical mods you may have made over the years to ensure there is enough slack.
7. I used the method of jacking the engine up from the forward oil pan, so I needed to remove the crank position sensor wire. There are 3 x 12mm bolts on the protective metal cover and 2 x 10mm nuts connecting the sensor to the engine. Note, the gasket on the sensor at this point should likely be replaced, but they are not available. See this thread on a method of using 2 O-rings instead. crank sensor? - https://forum.ih8mud.com/threads/crank-sensor.82601/. When re-installing the sensor, torque the nuts to 78 inch pounds (6.5 ft lbs).
8. Optional: I did not touch my exhaust, but it will see some stress. Removing the flange bolts at the catalytic converted would help, but my bolts didn’t want to move so I left it.
9. Loosen the 4 x 17mm engine mount nuts. First make note of how much extra engine mount stud is sticking past the nut. This extra length just makes it harder to remove the mount later. The bottom bolts are easy to get with a deep socket and ratchet. The top bolts are a bit tougher. You can get a box-end wrench on them, but it is unlikely you will have the leverage to break them free. I was successful with a ratchet and a cheater bar. My ratchet has a swivel head which helped. Otherwise, you may try a wobbler or universal joint. I loosened the bolts on the side I was not replacing, and obviously fully removed the side I was replacing.
10. Optional: I took a Dremel tool and cut off about ¼” of the lower engine mount stud. There is good access to do this. This allows the mount to be removed with slightly less lifting of the engine.
11. Run a cam strap or ratchet strap from the frame to the front axle housing on both the passenger and driver sides. If you don’t do this, when you lift the engine it will just unload the springs for several inches before the engine starts to lift.
12. I have a home-made transfer case skid plate that interferes with one of the bolts connecting the transfer case to the crossmember, so I had to remove it. 3 x 12mm. This may not be an issue with OEM or others aftermarket solutions.
13. Loosen the 2 x 17mm nuts connecting the transfer case crossmember to the transfer case mount. Deep socket required. This makes it easier to lift the engine. You’ll be fully removing these nuts later.
14. Give everything an inspection to see if you have anything left that will not survive lifting the engine about 4 inches.

At this point you should be prepared to lift the engine. Some people lift from overhead with and engine hoist, some lift by jacking up at the crank pulley, and others jack up from the front oil pan. I did the oil pan route. I placed a 4x4 across the entire with of the pan, and then configured a few wooden blocks between that and the jack.

Passenger side:

1. Fully remove the engine mounts nuts you previously loosened.
2. I shifted the jack slightly to the passenger side and started lifting. After about an inch stop and inspect how everything is doing, especially the engine fan and any electrical cables. If all is clear keep jacking. Occasionally test if the engine mount will come out. Do not put your fingers between the mount and the block/frame. A slipped jack could crush your fingers, so work from the sides. If the mount can’t be removed jack up a bit more and try again. Once clear, remove the mount.
3. Install the new mount. I took a cutoff wheel to the extra stud length as previously mentioned. When you do this, screw a nut down on the stud, cut the stud, and then remove the nut. Removing the nut will help clean up the threads. Once the new mount is in place, slowly lower the jack, checking to make sure the engine mount studs are lined up in the frame/block holes. Lower the jack the rest of the way and hand tighten the engine mounts nuts back on.

Driver side. Same process as passenger side

Transfer case mount:

1. Place your jack at the back end of the transfer case to safely support it.
2. Remove the 17mm nuts connecting the transfer case crossmember to the transfer case mount (you loosened these earlier)
3. Remove the crossmember. 8 x 14mm bolts.
4. Remove the transfer case mount from the transfer case. 4 bolts x 17mm
5. Install the new mount to the transfer case. I don’t see a torque value for this.
6. Re-install the crossmember. 45 ft lbs to frame, 55 ft lbs to transfer case mount

You should now have fresh mounts installed. Congrats. Now go put everything back together and enjoy your new smoother ride.

 

[LINUS]

That motor looks well updated & mounts don’t look the the only new underhood rubber - intake pipe sure looks fresh too, among other / heater valve.

 

[cartercd]

With the exception of the body mounts, I have replaced every rubber bushing, mount, and hose on this truck. Mr. T liked using rubber.

 

[FMC80]

This is a thorough and detail oriented write-up that is easy to comprehend. I’m what’s known as “mildly to moderately retarded” and I understood this tech without asking my 6 y/o daughter to interpret for me. Well done and great pics too.

Thank you for the write-up

 

[spensert5]

Did this today. I used the floor jack / oil pan method and was surprised by the amount of movement I could get out of the engine before any “eek” interference. I did wind up cutting off about 1/4” of each side of the stud on the motor mounts which helped a TON.

If I was to give a tip based on my experience it would be to bolt the mount to the engine first, as the slot on frame mount is elongated. This makes alignment a breeze when lowering the motor back down. I tried the reverse order first and trying to center the engine side hole over the engine side stud is a fools errand.

Stoked on a marked improvement with the new mounts. Butt dyno says throttle response is better and no more awkward shakes and rattle at the red light.