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Motor Mount Replacement Walkthrough [With Pictures!]
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Motor Mount Replacement Walkthrough [With Pictures!]
Here is the story of how I changed my motor mounts on my:
1994 S10 Blazer
4.3L, 4WD, Auto trans
169k miles, LT Tahoe edition
Original motor and mounts
Backstory: replaced water pump 6 months ago, could never seem to get the fan to stop rubbing on the shroud, cut 1/8" off shroud and problem still persisted. Shroud rubbing only got worse and would change with temperature, forward/reverse, speed bumps, etc. Then, it started to vibrate unusually when shifting from 2nd-to-3rd or 3rd-to-4th. Took a look at the mounts and they looked awful, so I decided it was time to replace them.
I am not a mechanic, but am slowly learning how to do more and more stuff on my own. After reading a bunch of other posts about how to replace them, I sprung for 2 of these Energy Suspension mounts:
for the sole reason of installation ease. I don't offroad or have a swapped motor or lift kit or anything like that. This is my wife's daily driver. A friend recommended I not use the Energy Suspension mounts because they increase frame vibration dramatically, to the point of annoyance, from his experience. However, he replaced mounts in a Camaro with an LS1, so this is not quite the same application. These mounts ARE harder than the OEM mounts, so, yes, it WILL transmit more vibration to the frame. However, now that I'm done, it's barely noticeable so no big deal to me. All-in-all, I'm so glad I went w/ these, because, as you'll see, I don't think I could have completed this job with OEM mounts.
I like to take lots of pictures when I do something like this. I regret not taking enough "before" pictures, so I will do my best to describe what's going on. Here is the worse of the two mounts, the driver's side, as seen from behind the front driver's side wheel: https://i.imgur.com/kaPW7Y6.jpg
As you can see, the rubber is cracked. In reality, the mounts have sagged about an inch. This one is actually resting on the frame, the passenger side is not as bad, but still degraded quite a bit. I'll show this in a picture later, but the mount is two pieces: the engine side screws to the engine block and the other side screws to the frame. There is no need to remove the frame-side portion of the mount. The two parts are connected with a center bolt. You can see this easily in the above linked picture. The bolt head is a 5/8". The nut was a 11/16". Others have noted that the 4WD version is the worst because the transfer case and driveshaft block virtually all access to the mount. https://i.imgur.com/kirTE7R.jpg
This is true, but there is another way to get at that mount.
First things first, disconnect your battery, remove skid plates, and spray all screws and nuts with penetrating oil. Put a floor jack under the oil pan w/ wood separating the metal jack plate and the metal oil pan. Try to get as much surface area of wood contact on the oil pan to prevent damaging the oil pan. I was really nervous about this, but it turned out fine - no damage to my oil pan. Jack the motor slightly to ensure you are supporting the weight somewhat with the jack.
I started on the passenger side first, because I thought it would be easier. I decided it would be easiest to take the starter off to get more access to the mount. I'm glad I did. Here's what it looked like: https://i.imgur.com/GDGntfU.jpg
I've actually already taken the mount off in this picture: see the frame-side portion of the mount w/ the through hole. The blue plastic thing is a magnetic flashlight, ignore it. The big black wire is the starter cable. The starter is on the ground to the left. The factory cable is a little short in my opinion. My starter cable is extended so it will reach the ground and not dangle. You can see the jack and wood in the bottom left. A side note on starter removal on this truck: it really sucks - on mine, I have to unscrew the flywheel cover piece and the two mount arms on the sides of the trans (you can see one of them hanging down in the above picture). However, you will have to get the starter out to get at the motor mount.
Next, put a 5/8" wrench on the front screw head and put a 11/16" deep-well socket on the nut. You will NEED a deep well socket here. On mine the screw head was on the front side of the motor and the nut towards the back. You can probably get the 11/16" nut off w/ a ratchet, but when I tried I could only move it 1 'click' at a time. So, I found the shortest air wrench I've ever seen (3/8" drive) and that worked beautifully. With the starter gone, you can get right up into the area where the starter was and get to the nut. With the nut off, you'll need to jack the motor up until the weight on the bolt is relieved and you can slide it out. Slide out the bolt.
Now, jack the motor up even more, say at least another inch, if possible. Others have said you need to remove the distributor cap to avoid crashing it into the firewall. I did not have to do this, but you might, so be aware. This is where I lucked out, I think. My mounts were actually so busted that the rubber had disconnected entirely from the engine-side mount. So, I did not have to chisel it off. You may notice the rubber flows outward when it sags, sometimes getting so close to the screws that a socket is tough to get in there. Raising the motor up should allow you to get a 9/16" socket onto the remaining engine-side mounting screws. It's possible you could have to chisel rubber out from the screws depending on how saggy the mounts are. I did not have to, fortunately. Go for the two outboard screws first. Fortunately, these screws are not torqued down super tight. Once you break them, you can unscrew them by hand as long as they're not super rusty. The tricky one is the third screw, it is boxed in by three tabs. More on that later. Again, hit these w/ penetrating oil first. It's all about finagling the socket and ratchet to get to these two screws. A shallow well socket worked fine for me. With the starter gone, the rear screw is fairly straightforward. The front screw is a little tougher to reach, but can be done without much trouble.
To get the third (last) screw holding the engine-side mount out, you will need to knock out the center part of the mount: all the rubber and the pivoting metal part w/ the center bolt flanges. Because the rubber has already ripped apart on mine, I just turned it a couple different ways and finagled mine out without much trouble. Took maybe 2 minutes. You may need to jack up on the motor a little more. With that middle part out, you get a LOT more access to the third screw. This is tough to visualize, so here's some after-the-fact pictures of my crappy mounts: https://i.imgur.com/BqhnU4y.jpg https://i.imgur.com/RXtfTzc.jpg https://i.imgur.com/cnkQwIX.jpg
You can clearly see where that third screw is from here: it's boxed in with three tabs. You'll also see I had to bend those tabs out to be able to get at the screw. I used channel locks and vice-grips to bend the tabs. The problem is: to get at the screw, you need to get the ratchet head in there. Forget about using a wrench unless you cut the tabs off - this is an option, but I didn't have any cutting tools available. This is where you may need to jack the motor up even more, to get clearance to get a ratchet in there. Just break it loose and you can unscrew the rest by hand. Once you get that screw broken, you're home free. This is what my passenger side looked like with the mount removed: https://i.imgur.com/RlJ1Et8.jpg
There is a little spacer plate you have to include when installing the new mounts. Follow the instructions that come with the mounts for the orientation of the spacer. It's straightforward. Installation is basically the reverse of the above. Start by aligning that spacer and the block in place and get the three screws started back. This is where the aftermarket mount pays off: no annoying tabs to make it tough to get that third screw back in place and tight. I am at a loss for how you'd even do it, unless you had some specific extensions that would let you get in there close enough with a ratchet. The Energy Suspension instructions call out torques, but there's no way I could get my torque wrench in there, so I just winged it. Once you get the three screws installed, lower the motor until the through bolt lines up and pop it in. Reinstall the nut and tighten just like you loosened it: I used the air wrench again. One note: I was unable to get the little heat shield back in place. The holes won't line up. You can probably modify the holes easily, but I didn't have any cutting tools. I think I'll just throw some high temp insulation around the exhaust headers if I get worried about it, but I'm not concerned at the moment. Here's what it looks like when done: https://i.imgur.com/oPBsvE2.jpg https://i.imgur.com/FpQ7MIr.jpg https://i.imgur.com/Z0FrpPV.jpg
Now, onto the dreaded driver's side mount! This one gives people nightmares because the transfer case is in the way. Forget about getting access to anything from above - there's no room. I didn't want to go through the hassle of trying to remove the transfer case and driveshaft, so I found another way. It turns out, you can get an 11/16" wrench on the through bolt nut by going through the driver's side wheel well. I did not have to remove the wheel. https://i.imgur.com/3bpG2TG.jpg https://i.imgur.com/CykNqem.jpg (note the through bolt has a sharp nose on it, you can barely see it through the wheel well)
For this one, I put the 11/16" wrench on the nut through the wheel well, and finagled the air wrench through the front side, where the belt is. Keep in mind, the air wrench I used was really short. I've never seen one so short. It worked. Next, lower the motor until you relieve the through bolt and slide it out. Now, jack the motor up to get to those screws (keep an eye on distributor cap as well). You can get to the front screw and the boxed-in screw via the front. I bent a couple tabs from the front to get my ratchet in there. You have to get the rear screw off through the wheel well. It can be done. Do the same thing as before: take off front and rear screws, knock out middle portion of mount, then tackle that third screw by bending the tabs and jacking the motor up as needed. Unfortunately, I don't have good pictures of this process. Install the new mount exactly like the other side. Lower the motor until you can pop the through bolt back in and use the wrench on backside / air wrench on front method to tighten it: https://i.imgur.com/R0rHwig.jpg (through wheel well) https://i.imgur.com/tAeAJQ3.jpg (through wheel well) https://i.imgur.com/vzPBOry.jpg (front view)
Now, lower the motor fully (if not already down) and remove the jack. When I got done, my motor was sitting a full inch higher and not rubbing the shroud anymore. https://i.imgur.com/KP8hNlY.jpg
Don't forget to reinstall your starter, replace skid plates, and reconnect your battery!
I cranked and felt the motor vibration with the new mounts. If you lean against the truck body at the wheel well, you can feel more vibration passing through the body, but it's nowhere near as bad as I was thinking it would be.
Voila! Newly mounted motor!
Work time: started 11am, finished 8:30pm, 1.5 hr lunch. Everything went better than I expected!
Cool writeup - The original starter is a pain to remove. Done it myself on the exact same model. Yours looks fine too - no big rust. Hope it keeps you going for a lot longer.
Great writeup, Thanks! I got as far as beginning to remove the thru bolt yesterday afternoon and seeing how sloowww that was going to go, with an hour of light left, I buttoned things back up. Great to see this, I've got a much better idea of the rest of it now. Did you even jack the vehicle up or just the motor? btw, I always throw a piece of 5/8 or 3/4 plywood under the oil pan and then the 2x4 to distribute the weight better, being careful not to have the ply resting on the oil drain plug that drops down a bit.
Great writeup, Thanks! I got as far as beginning to remove the thru bolt yesterday afternoon and seeing how sloowww that was going to go, with an hour of light left, I buttoned things back up. Great to see this, I've got a much better idea of the rest of it now. Did you even jack the vehicle up or just the motor? btw, I always throw a piece of 5/8 or 3/4 plywood under the oil pan and then the 2x4 to distribute the weight better, being careful not to have the ply resting on the oil drain plug that drops down a bit.
You should be good with the new mounts.They may be a little stiff at first, but will eventually break it self in.You won`t have to ever change these mounts out evr again.
Well, I am back working on this issue again. Why? The same thing that clued me into this problem is happening again: the fan is interfering with the shroud quite a bit. So much so that about a mile down the road I smell burning plastic + the noise! Rather than screw up the water pump, I decided to tackle this problem again.
So... what happened to the mounts? My theory is: I've had a gas leak for a while but couldn't pinpoint the source. I finally realized it was leaking under the shrader valve on the fuel injector intake block running into the plenum. See the thing w/ the blue cap here:
I think what's been happening is: the gas slowly leaks off this intake block and drips down the block, eventually settling on the driver's side motor mount. I don't know if it's the heat (and lack of heat shield on the exhaust headers) AND/OR the gas breaking down the polyurethane mount, but it seems to have happened.
First, I took the plenum off to replace the fuel injector blocks. I've replaced the spider injector and these parts a few years back, so I'm somewhat familiar w/ the process. I had not planned to replace the spider, since it's only < 5 yrs old. The first one made it > 15 yrs before replacement. However, when I looked at it, the hoses had nearly rubbed all the way through for at least one port. Here's some pics:
Here's some more tips for those replacing their spider: don't do what I did: I incorrectly assumed the torx screw that secures the mounting plate for these two injector blocks here:
FYI: I had a rough time w/ this fastener the first time I replaced the original spider too. I think it's got threadlocker on it or something. When you replace, make sure you use anti-seize. Also, there are not many tools that can reach into the area and you will be working blind. This is what I finally used that made it a lot easier:
A tiny 1/4" ratchet w/ a T30 bit in the end. Worked great!
Well, I rounded the torx receiver out of the fastener, so I had to get creative. I bent the heck out of the mount plate "ears" like this to relieve some of the preload on the fastener:
I finally got it replaced, but that fastener took more time than everything else combined.
Once I dropped the new spider in, I tried to route the lines so they wouldn't rub, but they're so stiff, I couldn't entirely prevent the rub. So, I wrapped a little electric tape and wedged some ear plugs in there to try and keep the vibration and rubbing down. Maybe it'll last a bit longer.
Anyway, this is where I'm at now. Not quite done because the o-rings on the fuel lines took a while to find. The inlet line has a slightly larger o-ring than the return line:
Turns out rockauto has a bit more definition for these.
The inlet o-ring is: AC Delco part #: 217452
7.35MM ID X 1.66MM THK
The return o-ring is: AC Delco part #: 19258137
6.07MM ID X 1.30MM THK
I live really close to an O'Reilly distribution hub, so I can get most anything in their supply within hours, so I prefer them. O'Reilly does carry these o-rings under the AC Delco part numbers, though the return o-ring is a "special order" item, which takes 3 days or so to get in hand. This is what I'm waiting on to button the plenum back up.
Moving on to the motor mounts: I am starting to figure out my approach to replacing the driver's side mount. Here are the energy suspension instructions, FYI:
The plastic has bulged and flowed a little bit, covering the head of the screws. I think maybe I'm going to have to use a chisel for this one. Looks like it's "sunk" about half an inch or so:
Still a little bulged, but not nearly so bad. Thank goodness, as I do not want to take the starter off again.
So, still don't know how I'm going to tackle the motor mount yet. I planned to use the same procedure as my original post. Open to suggestions if anyone has them.
Well, the saga has come to a close. After I got the spider replaced and plenum built back up, I decided to do another check. During this time, I realized the smell I was experiencing was not melting motor mount but melting serpentine belt. The compressor pulley had seized. Ok, changing gears to something new (to me).
First, lots of special tools are needed to take apart an R4 compressor. I rented them all from AutoZone. Another important note: instead of taking the compressor off the engine, I opted to take the top of the radiator shroud off. As you will read below, I got very far into the project before I bit the bullet and took the compressor out of its mount to get better access. But I did NOT have to take the refrigerant lines off (thankfully!). You shouldn't have to either.
Moving on:
This thing is a must-have to be able to grip the front of the compressor to be able to get anywhere: https://imgur.com/vuhn2P8
You will need a puller tool AND an installer tool. There are a bunch out there. I will show what I used in pictures below, but I had to cobble together solutions as you'll see coming up.
Important note: Google tells me there's 2 versions of the R4 in existence: one with a 3/8"-24 threaded compressor shaft and one w/ metric threads (I think M10-1.0, guessing). I took the nut off and used a thread gage to find I have the 3/8"-24 version. Strangely, the 9/16" socket didn't fit in the hub, so I had to use a 14mm socket instead. It is important to figure out which one you have as finding an installer, which will thread onto the compressor shaft, might be tough depending on where you live. The two available for rental at O'Reilly Auto were both cross-threaded to the point of uselessness. So I had to go to AutoZone. This is why I say it'll be nice to know what threads you have. I actually took my nut to the store and test-fitted it and the installer tool on a thread gage stud.
Once you push the clutch off, next will be the pulley. Note, when you take it off, make sure you keep the keyway, the little rectangular piece of metal that keys the shaft to the clutch. The replacement I bought at O'Reilly Auto did not have one. https://imgur.com/C0g8xjn
Next is the pulley. Mine would not turn at all. Here is where you can see something I thought was very bizarre. I don't know if this is what caused my problem, but it is unusual: the pulley outer rim broke off at all the little webs all around the diameter: https://imgur.com/UdLSmu7 https://imgur.com/fKwxbwo https://imgur.com/Q8b34nz
If your pulley is truly seized, you will have to pull it off w/ a puller tool. I used a 3-arm gear puller to do this, but there are no doubt several pullers that will work for this. See later pictures to see a couple versions.
Next, comes the hard part. Well... hard for me (read: time-consuming). Putting the new parts back on took some creativity given the lack of tools. More details to come. As far as parts, all my parts were probably fine except the cracked pulley, but I replaced everything just in case.
First, install the coil. This is tricky because the outer white ring on this coil is ceramic, and should NOT be hammered on w/ a hard metal device (i.e. hammer). Several youtube videos are out there saying to put something on the inner metal lip and tap on that to get the coil into position. That proved to drastically extend the time it took me to finish this project. I used a short stubby screwdriver to bear on the metal lip and tap this onto the hub. It took quite a lot of tapping to get it into position. In hindsight, this is where taking the compressor out of its mounts to get better vision would've helped, and probably caused a lot of headache for me. The root issue is: the inside metal lip is SOFT, and pinging it w/ something, especially something sharp like a screwdriver, deforms it, and this can cause trouble when you put the pulley on. https://imgur.com/A58VGWh
Turns out the deformation I made on the coil metal lip earlier mashed the metal into the gap where the pulley slides in and jammed it. So... I unbolted the compressor so I could get better vision, and used my Dremel to grind down the burrs I made. Then, I resumed pressing it own until it bottomed out: https://imgur.com/ZaxrcqA
Next, return the snap ring. Flip your pliers if they're reverse-able like mine: https://imgur.com/9mpzzph
I ended have to press the pulley on and off 5 or 6 times before it finally freed up in the fully installed state: https://imgur.com/eWZgLia
Lastly, the clutch. Lightly tap the keyway back into the clutch groove, line up, and install the clutch onto the shaft. https://imgur.com/pfdP813
Use the installer tool and the clutch spanner wrench mentioned up above to press the clutch into position. Make sure you line up the keyway before you start pressing. https://imgur.com/hRjwJkK https://imgur.com/pCSYJjH
There are a bunch of numbers floating out on the internet about the air gap needed to keep between the pulley and clutch. I went with one suggestion I read: about a business card's size gap: https://imgur.com/LLt8Ujf
Nicely written, I was looking for info about the Energy suspension engine mounts, I probably have to replace mine because there is a "thump" sound whenever I gave it hard acceleration, I'm glad I found this. I think the part number is different for 95+ blazers, 31144, also I think I need to replace the transmission mount.
Everything seems pretty good, the only thing that is bothering me it the wedged are plugs and the electric tape inside the plenum, bad idea, they are going to get sucked by the engine eventually.
I just replaced the spider in mine, I had to clean everything, it was a mess.
Now my next problem is a leak in transmission and engine oil.
As you can see in my previous post in the second photo is from the upper intake, you would probably notice the flow of the intake, after it passes the throttle body it gets divided and blows directly on top of the injector spider then it goes to the top perimetral holes that are connected to the center ones, if those plugs or the tape come loose they will get absorbed by those perimetral holes and get into your engine, probably will not cause any major damage, but I would not risk it.
02-22-2015, 10:29 AM
Motor Mount Replacement Walkthrough [With Pictures!]
