Motor Mounts
I had recently picked up a 2003 c32 with 157,000 miles on it for a very competitive price. A car with this many miles of course has its share of problems. One of the big annoyances I've been working through lately has been shaking on idle when in park, but most noticeably when coming to a full stop and also when in drive, foot off the brake and gas, creeping uphill.
After looking through a number of threads, given the mileage on the car and not finding the service performed in the history, I decided to change out the transmission and motor mount. I'm relatively handy and have done a number of larger service items on my other cars like head gaskets and timing belts. On a difficulty scale of 1 to 10, 10 being an automatic transmission rebuild, I would rate this a cool 5.5.
Although this didn't fix my rough idle problem (the search continues), the last "guide" I saw on this forum was from 2010, I figure a procedure without pictures (my hands were way too dirty to handle a camera) may help others here. hey, figure I might as well make my first post useful to someone.
So, tools needed (that I can remember):
Jack, jack stands, block of wood to hold the motor
8 mm socket for the under carriage shields
12 mm socket for the lower motor mount bolt
5/8" regular and stubby wrench (Home depot sells a set of SAE Husky stubbies for $14) for the upper motor mount
Various assortment of pry bars, pipes and 2x4's to lever the engine
Parts Needed (and costs for those who care):
Motor mounts. I went with the cheap Uro engine mounts from rockauto for approximately $80 shipped for the pair.
Directions:
1- Take off the air filters, airbox, inlet to the throttle.
2- Take one of your 5/8 wrenches, get it over the top motor mount bolt by feel (you can't see much), use a pry bar and lever against the fire wall or lower subfram to loosen the bolt. Doesn't matter which side you start on.
3- Remove bolt and heatshields.
4- Jack up the car and place on jackstands
5- Remove both sections of the lower shield
6- Take the 12mm socket and loosen the lower motor mount bolts. At this point, the engine is resting on the mounts without any bolts holding it in.
7- Place the floor jack under the oil pan. Place a block of wood between the oil pan and jack. Lift the motor up about 3-4 inches (Don't go "as far as you can")
8- Take the passenger side motor mount out. You should take out the heatshield from above first. You can then take out the actual motor mount from the bottom. I found the most space between the crossmember and the firewall passing the engine mount towards the back of the car. It was definitely a tight squeeze. Don't be tempted to put in the new mount yet. You'll need the room for the Driver's side mount.
9- The driver side motor mount took the most amount of time and effort. I ended up removing the mount from the top instead of going under the car. The heatshield is attached to the oxygen sensor wire. The heatshield can stay in, but take off the rubber covering to give yourself a little bit more room. Every little bit counts here.
10- Rotate the mount sideways so the top mount hole points toward the passenger tire and the bottom toward the driver's.
11- Take your 2x4 (I used a 7ft piece) or large pry bar and pry against the motor to shift it toward the passenger side, thereby giving you more clearance to squeeze the motor mount pass the ac compressor.
12- Pry, curse, bleed and cry a bit. The mount should clear and will be in front of the radiator fan.
13- Remove the rubber shroud from the new mount put some antiseize on the threads and follow the same path the old mount came out. Put the rubber back onto the mount after you clear the obstacle course.
14- Do the same for the passenger side mount now.
15- Start with the top bolts on both new mounts. This was tricky. Ignore the locating tab until you get the first thread started. Finger tighten the bolt and leave enough wiggle so you can properly align the lower bolt.
16- GENTLY lower the engine a little bit. Don't rest the engine on the mount and leave yourself enough room to move the mount around and thread in the lower bolts, just the first few threads, don't finger tighten.
17- Go back up top and clock the heat shield, rubber shroud and mount tang to align with the engine. Tighten the upper bolt just enough to hold the position, Don't try to crank it all the way, remember, the jack is still holding the engine.
18- Lower the engine into its final position. If everything went well, the mounts will be clocked correctly and should line up correctly with the bottom holes. Remove the jack.
19- Crank all the bolts down. I don't have the TQ specs on hand, but the bolts do not take a lot, hell they're 12mm and 5/8".
20- Clean everything up, you remembered to replace the lower shrouds right? Don't forget the intake and air boxes! Double check for engine-bay wrenches and crack open a beer!
The procedures took me approximately 4 hours to execute without any help. A second pair of hands would've been helpful when rocking the engine and trying to align the bolt holes. I also spent a lot of time figuring out how to take out the driver's side mount, I even removed the sway bar mount which was unnecessary for the way I did it. I would target this for 3 hours the next time I do it.
Hope this helps someone. I'll try to check in and respond if there are questions.




