M62 Alternator Removal / Replacement (Water Cooled) Pre-Steps 1. Disconnect Battery Positive lead 2. Charge Your Battery with battery charger to full charge (So you new alternator wont have to work as hard) 3. Make sure you have Coolant available to replace what spills (Mine was 1.5 gallons) 4. Have a Sealant available, Silicone or RTV (I used Red RTV= High Temp) Begin Removal 1. Remove Fan Shroud a. Remove 2 plastic pop pins and clip around expansion tank b. Remove top of Airbox to free up space, undo air hoses c. Remove Airbox bolt to make it easier to get out d. Lift up fan shroud, and disconnect hose at bottom of expansion tank (Flat Screwdriver) e. Disconnect 2 electrical plugs under expansion tank f. Move fan shroud up and out of the way 2. Remove Fan a. Using a large wrench and hammer, place wrench on the Nut and hit the wrench with the hammer to create an impact to loosen the nut. (The Nut is REVERSE Thread, so hit it like your tightening it, (righty tighty, lefty loosey)) Once the nut is knocked loose, then you can just unscrew it. b. When putting it aside, keep the fan vertical, don t lay it down, maybe lean it on the wall, or bench, so the Fan Clutch fluid doesn t disappear, never to return c. When re-installing it, also hit it with impact to tighten, and remember it is reverse thread. 3. Remove Serpentine Belt a. This would be a good time to snap a picture, or draw how the belt goes around the wheels and pulleys, when it come to re-installation b. Loosen the Belt Tensioner Bolts, there are 2, notice one of them appears to have a big nut attached to the back, that nut is stationary, so only loosen the bolt for now. c. Once loose, the belt tensioner will swing freely, allowing the belt to be removed with ease. 4. Remove Belt Tensioner/Idler Arm a. Remove the dust cap over the Idler Arm Pulley (With Small Flat Head Screwdriver), to reveal Torx Bolt. b. Using a #45 Torx bit remove the bolt and this releases the Idler arm/belt Tensioner. c. Remove the 2 bolt mentioned above in 3b
d. No we have a free shot at the alternator 5. Remove Alternator a. Remove (6) 10mm Bolts from the Alternator housing, these bolt hold it into the coolant canister. b. Unplug the electrical harness, I believe this is the voltage regulator c. Unscrew the nut that hold on the large output cable d. The alternator is now free. e. Turn it around 180 degrees, and try to pull it out, make sure you do not damage the radiator in any way f. I had to remove some more coolant hoses to get it out, some say you don t need to remove more coolant hoses, but I did, just in case. g. I removed the hose going to the canister, and the top hose going to the water pump h. Now your old alternator is out, and the hard work is done, it is easier to put it all back together, then to take it apart for the first time. Begin Re-Installation 1. Re-install new Alternator a. Clean off surface of alternator housing where alt will be sealed in the coolant canister b. Apply small bead of sealant around Alternator gasket c. Put new alternator in it home and re-attach the (6) 10mm Bolts, tighten them down some. d. Wait about 15-20 minutes to let Sealant set, and re-tighten down the Bolts. (Wait longer if engine was cold to begin) e. Re-attach Electrical harness, and Output wire f. New Alternator is in. 2. Re-install Idler Arm/Belt Tensioner a. Re-Install with Torx bolt, making sure the wheels are down, and the 2 bolt holes are up. b. Insert the 2 bolt for the belt tensioner from 4c c. Re-install the Serpentine belt, making sure the ribs are the right way, and it running in correct pattern d. Tighten down the Belt Tensioner, as tight as possible, you may want an extra hand to keep pressure on it, as you tight down the bolts e. Now that the belt is on tight, and the alternator is in, just go back and put everything back together, remember the Fan is reverse thread, and hit it with an impact to seat it. Once everything is back in place, don t forget to top off the coolant. The whole procedure should not take more than 2 hours.
Faisal Ahmed (Faisal in Laurel, MD)