The engine in the 996/997 hangs from the motor mounts rather than sitting on them as in most other cars. As a consequence of this design, it’s hard to tell by visual inspection when they’ve worn out. As they stretch and degrade over time the car may idle rough or one side of the exhaust may appear to hang lower than the other. Once you take the mount off of the car, you can see as in the photo above how the old one is distended compared to the new one.
The replacement procedure is very simple and can be done by any shade-tree mechanic with a good floor jack. Jack-stands for the rear of the car help, but are not required. One could just park the car on some 2x4s to get a little additional working room and easily make the swap with just the jack. We recommend using jack-stands just because it’s easier to move around under the car. Make sure the engine is cold before trying to move your hands through the exhaust-header to get to the lower nuts. As long as you only remove one mount at a time, you don’t have to worry about repositioning the engine to make it line up with the mount. You can choose to use stock mounts; solid motorsports mounts; or semi-solid. I went with stock.
Tools required: Socket wrench; torque wrench; 13mm socket; 18mm socket (deep); and a 6 inch extension. Parts needed: Two replacement mounts, Porsche Part Number 993-375-049-08-M270 (for 1999-2005 non-turbo 996.) [Yes, that is a 993 part number, and yes, it is correct.] 997 Porsche Part Number is 997-375-049-08. If you are going to Track your car, consider upgrading the motor mounts to a more solid design. You’ll get less engine movement at the price of bit more vibration at idle.
Like all of our DIYs posted here: Proceed at your own risk — no wagering. These instructions are intended to familiarize you with the process and are not a substitute for a good shop manual.
- Safely jack up the rear of the car and place on jack-stands.
- Place the floor jack under the engine just behind the oil pan as seen in the photo. Use a block of wood (or a hockey puck) to avoid damaging the engine.
Support the weight of the engine with the jack but do not lift the car off of the jack stands.
- Remove the air box.
- Loosen two bolts and swing the secondary air pump out of the way.
- Start at the right mount and remove the lower nut using a deep 18mm socket and a 6 inch extension.
- Remove the two upper bolts with a 13 mm socket and remove the old mount.
- Inspect and clean the area where the mount sits in the chassis.
- Insert the new mount. Install two upper bolts and torque to 23 ft lbs. (M10 bolts) or 17 ft lbs (M8 bolts) depending on your car.
- Install lower nut and torque to 63 ft lbs.
- Repeat procedure on the left side.
- Replace secondary air pump and air box.
- Lower car and inspect exhaust tip position.
- Drive and sag no more.