How to Replace the Engine Mounts on a 1999 Chevrolet Tahoe

Engine mount replacements are one of those things that typically fall into the category of "easier said than done." There's no real magic or special skill-set required when replacing engine mounts especially on a big truck like the Tahoe; it's mostly just elbow grease, and comfort with moving things heavy enough to crush your appendages of choice into puddles of goo. But as long as you're careful and systematic, replacing the mounts on a Tahoe is really very little more difficult or dangerous than the average brake job. Seriously.

Instructions

1

Park the truck on a smooth, level surface; kick a set of chocks behind the rear wheels, lift the front end of the truck enough to get the front tires off, and lower it onto a set of jackstands. After you remove both of the front wheels, you may want to drop the frame down a bit onto a lower set of jackstands. Lifting the Tahoe high enough to get the tires off will put the bottom of the engine nearly two feet off the ground, and your jack may not reach the bottom of the oilpan.

2

Slide your floor jack under the oilpan, and place a piece of two-by-six on top of the jack pad. Be very careful here. First, make sure that the jack pad is perfectly centered on the oilpan at full extension. Raise the jack just enough that you can't slide the wood out from between the jack pad and the oilpan. You don't want to load the jack with the weight of the engine; you only want to keep the engine from dropping after you remove the mount bolts. Remove the ducting from the air cleaner to the engine.

3

Remove the clamp from the lower radiator hose, drain the cooling system into a drain pan, and then remove the upper radiator hose. Technically, you should do this before messing with the mounts, but it may not be necessary if you can get the requisite hand clearance without removing the hoses. You may want to try lifting the engine first to see how much clearance you need. If you do opt to leave the hoses on, then watch them very closely as you lift the engine.

4

Identify the motor mounts; you should have easy access to them through the wheel-well openings. There are two schools of thought on mount replacement at this point. The ASE-approved technique is to remove both of the mount through-bolts and lift the motor straight upward. The alternate technique is to remove one bolt, pivot the engine upward on the other for clearance, and replace one mount at a time. Removing both bolts reduces the odds of damage to the mounts during installation, but increases the odds of damage to the distributor, and makes realignment more difficult. It's your choice, but, if in doubt, remove both bolts and closely monitor the distributor and linkages.

5

Loosen and remove the nut on the mount through bolt, and use the top of your ratchet to tap the bolt forward until its end is flush with the mount. Once you have the bolt head moved forward by half an inch or so, clamp the bolt shank just behind the head, and tap the pliers forward with a small hammer to pull the bolt out. If the bolt wedges, then try lifting the engine very slightly with the jack to take some pressure off of the bolt. If you've opted to remove both bolts and lift the entire engine, then repeat on the other side. Do NOT push on the engine for any reason.

6

Remove the three bolts that secure the rubber motor mounts to the truck's frame, and watch that you don't drop or lose the nuts or washers. Slide the new mounts in as the last came out, and torque the mounting bolts to 44 foot-pounds; torque thee nuts to 33 foot pounds. Blue threadlocking compound isn't required, but many mechanics prefer to use it on motor mount bolts.

7

Carefully lower the engine back down so that the mounting assembly brackets on the engine slide down over the mounts. When you have one mount nearly aligned with the bracket hole, push the bolt into the bracket hole. This is where some muscle, finesse and an assistant come in handy. Play with the jack height or rock the engine very, very gently until you can get one of the through bolts to slide in. Lightly tap the head with a small hammer or your ratchet head to get the bolt far enough through so that the thread show on the back of the mount. Hand-thread the nut onto the threads.

8

Repeat this procedure on the other side; it should be a bit easier now that you have the first bolt in and the engine aligned. Install the nut, and tighten both through-bolt nuts to 50 foot-pounds. Again, medium blue threadlocker isn't required, but many mechanics use it for mount through bolts. Once you have everything tightened down, reconnect the radiator hoses, and refill the system. Put the wheels back on the truck, start the engine and allow it to idle. Add coolant as necessary. Keep an eye on your coolant for the next week; coolant levels will drop as air bleeds from the system.