Tutorial: 940 Engine Mounts Replacement

[writer100]

I am creeping toward stage 0 on this 17-year-old car.

Here's what I have done so far:
ball joints
sway bar bushings and end links
new radiator, hoses, heater control valve, expansion tank
new transmission mount
new Bilstein struts, Boge strut mounts, and control arm bushings
new plugs, wire set
the engine mounts, however, were still original. While they were not trashed, I did notice engine shake upon startup and cranking. They also had surface cracks in the rubber. I decided to replace them.

The old driver's side mount, with bracket stud visible:

The local Volvo dealer quoted me $100 per mount. Volvo Parts Online misidentified the part; originally they quoted me $24.95 which I thought was too good to be true. It was. That price was for the old solid rubber mounts. The correct hydraulic mounts were $70 each. Economy prevailed and I decided to try the ever popular Uro mounts for $32 each.

Here's what you need to do this job:

jack stands or ramps
floor jack
miscellaneous wood to elevate the jack
chocks or other means to block your wheels
a good block of wood with a groove to allow clearance for the oil drain plug

a six-point socket set, preferably half-inch drive, with a universal and as many extensions as you have
box end wrenches, preferably six-point
a bench mounted vise
safety glasses
a light
anti-seize
PB Blaster penetrating oil

I assume no liability for any damage or injury arising out of your attempt to do this job. If you doubt your abilities, bring the job to a professional mechanic.

Safely situate the car on ramps. Place into Park. Chock the rear wheels.

The engine/transmission is supported by the transmission mount and by two hydraulic engine mounts. Each engine mount is secured to a bracket with three 13 mm fasteners. The engine mount secures the engine with a 15 mm fastener.

Although similar, left and right amounts are not exactly symmetrical. The driver-side mount bracket is secured by 3 studs on the top of the frame rail. However, the passenger-side mount bracket is secured by two studs on top of the frame rail, and a bolt accessible from under the car. Also, the passenger-side mount requires the removal of the exhaust manifold heater hose bracket, which is affixed with four rusty bolts.

A few days before you start this job, it is not a bad idea to hit all the fasteners with PB Blaster, especially if you live in an area prone to corrosion. You really want to avoid rounding off these nuts. For the same reason, try to use 6 point tools.
Position the jack under the car. Ensure that it has enough reach to jack the engine. I had to position mine on some 2 by fours to raise it adequately. Don't start jacking yet, though.

Before you do anything else, loosen all your fasteners. Don't remove them, just crack them loose. If you cannot successfully remove them, you cannot go any further.
Next, remove the exhaust manifold heater hose bracket. Put the hose out of the way, if you still have one.
Remove both left and right 15 mm nuts. This is where the universal joint comes in handy. It is easiest to join several extensions and rachet above the engine.

Then, remove the bracket nuts from the bracket on either side. I did the driver-side first. Mostly, these are accessible by socket, but I used a ratcheting box end wrench on one of these, because nothing else fit.

Here's where you have to be careful. Position the wood block under the side of the pan you are raising (i.e., driver or passenger) and carefully start jacking. Make sure that your block does not wedge on the crossmember. You really want to jack the engine as little as possible, because items such as radiator hoses, heater hoses, and automatic transmission lines can be placed under strain. (A week later my aftermarket heater control valve failed. Coincidence? I am not sure. ) I jacked incrementally stopping to take a look. After a while my girlfriend became involved in the drama, as well, and shouted out to me when she saw the engine move. What I tried to do was lift the engine enough on one side to wiggle the mount/ bracket assembly out, but still leave the other side engaged in its hole. I didn’t want the engine drifting out of its alignment.
As you lift, keep an eye on the heater hoses, etc, for excessive tension. When you get enough clearance, remove the mount/bracket assembly.

Place the bracket into your vice, and remove the nut from the underside of the mount.

Replace the old mount with the new, engaging it correctly into the mount. I did not have torque specifications, but I used the tightness of the old mounts as guide in tightening the new. No loctite was used in my original mounts, but you may wish to do in the new ones.
Replace the new mount/bracket into the engine. Keep all the nuts loose until the engine bracket is engaged properly, then lower the engine down, and tighten the bracket nuts only. You may wish to use antiseize on these studs as well. If you don’t have a belly pan, you will now realize why they are a good idea. Do not tighten the top nut, but I screwed mine on it a few turns, to keep it from coming off.
The passenger side is similar, but the third bracket bolt is reached from under the car.


Picture of the third bolt from under the car:

Drop the jack entirely, and move the block of wood over to favor the passenger side. Then jack again, trying to keep the driver’s side mount engaged. I was able to do this. Remove and replace as above. Tighten both 15 mm nuts securely. Reattach the preheat hose assembly, using antiseize on the four bolts.

So far, my Uro mounts work well. The engine feels more secure and steady, especially when starting.

[billofdurham]

I am creeping toward stage 0 on this 17-year-old car.

I hope you aren't wearing an MVS T-shirt if you haven't arrived at stage 0.

Another good write-up heading for the Repair Database. Thank you.

Bill.

[Lou Rosenbaum]

just what the doctor ordered read the tutorial a couple of times and went for it. It was right on even the tips ie pre oiling the nuts a couple of days a head, six point wenches are a must for the rusted bolts. after market mounts worked fine at half the price. 2hours
thanks Lou R 93 945 380K

[98T5]

I recently tracked down the rattling of my engine to be the motor mounts as well. I will be happy to tackle this job because it seems pretty straightforward.

Were the bracket bolts easy to get to on both sides?

[writer100]

They were not bad if you have the extensions I pictured. Be careful how high you hoist the engine; it puts a strain on the heater hoses and heater control valve. Good luck.

[98T5]

They were not bad if you have the extensions I pictured. Be careful how high you hoist the engine; it puts a strain on the heater hoses and heater control valve. Good luck.

Where is the heater control valve located? what side of the engine?

[writer100]

the rear of the engine; they exit the firewall.

[Gula]

Sorry to revive such an old thread, but after my mount replacement my fuel and temp gauge stopped working. Any ideas?

[93Regina]

Here's what you need to do this job:

Installing motor mounts...on a 940...use a cherry picker and place it perpendicular to vehicle, and hook on to front engine hook at thermostat. Then loosen mount bolts and move cherry picker a few inches towards engine. Engine will rock up/over a pinch.

Note - I have a long extension cherry picker...so YMMV.