How do you change the alternator on a 1998 Cadillac STS?

Answer 1

I can answer this question because I have just done it. It isn?t as bad as what I heard it was going to be, just time consuming, and will take about 3 1/2 hours to get it out and 3 hours to get it back in. It starts like this: Disconnect both sides of the connections on the battery + and ? Jack the car up to about 18 inches of clearance underneath Remove serpentine belt and let it hang. Take off all three plastic shields off of engine compartment (right wheel well, splash panel-under, and radiator cover, top) Remove both front headlights, remove hood latch carrier plus latch and cable. Remove protective foam and top radiator hold downs (2). Remove radiator hoses. I did not drain the antifreeze as the drain plug was hard to locate and most of the hoses are up where you can get at them. Disconnect the AC condenser and lift away from the radiator. Remove the two radiator spacer flaps; remember how they go back on as my two were differently shaped. Remove fan bolts from radiator. Lift the radiator gently out of its rubber shock absorbers and lean slightly forward. Very carefully snake the dual fans out the left side and up past the radiator without dinging the radiator. If you are not sure of yourself put a piece of cardboard between the two so that they don?t bump together. With the fans out of the way you can now disconnect the upper and lower transmission lines. You can pull up on the radiator and lift it all the way out. It slides into little slots so you may have to give it a slight tug to break it loose. There is one little coolant line in the lower left corner of the radiator, make sure you disconnect this hose before you lift up. Now the alternator is fully exposed. There is a ground in the front, a connector block in the back, 4-5 bolts and two coolant lines that run in and out of it. I cut mine with a sharp knife knowing I was replacing with all new rubber hose, buy two feet of it at the auto parts store, this will cover everything you need. The new hose is not form fitted like the original was, so plan on buying a few zip-ties so you can anchor the new hose to run the same course as before. That?s pretty much it, I made a detailed list of everything I did and kept all the bolts in marked baggies so I would not forget where they went. Put in your new alternator, cut the new hose the same length as the old and reverse the process on this list. Do not be tempted to reinstall the fans connected to the radiator as one whole unit, if you do this you will not be able to get at and tighten the lower transmission line. Do it just like you took it out and remember in your mind about the little slots the fans and condenser slide into. The most time consuming problem I ran into was trying to slide the original Cadillac compression clamps back up onto their old slots on the rubber radiator hoses. If I ever do it again I would get the radiator clamps that tighten with a screw driver or a 5/16ths socket. Replace lost anti-freeze, check Transmission Fluid level and recharge AC with Freon. There you go, that is pretty much how it is done. May the Force be with You. I pretty much agree except there is no need to discharge the AC. There were changes over the years. On a 98 STS remove the upper radiator cover, then remove the hood latch frame and set on top of the engine unbolt the oil cooler lines from the left front side of the radiator as you are facing it. The lower line has a long fitting which usually rusts to the tube and the tube twists off so you have to replace the lower oil cooler line, $44 from Cadillac unless you are lucky. Unbolt the headlights, 2 bolts ea. and unsnap the electrical connections, set aside. Remove the 2 bolts from the AC condenser that hold it to the radiator, lift it up and move it forward. Unhook the fiber flap on the driver's side from the raditor. Remove the retaining bolt for the upper transaxle cooler line from the fan shroud. This will be easier to do if you at least remove the upper part of the air cleaner. Unbolt the 2 upper raditor retaining bolts and brackets and lift up on the radiator and tilt it forward. remove the 2 radiator hoses from the radiator. remove the upper transaxle cooler line from the quick release connector. Simply slide the plastic retainer back on the line and remove the snap ring with a small screwdriver, then pull the line out Now you can tilt the radiator further forward and remove the bolt that holds the oil cooler lines to the fan shroud (lower passenger side) and the electrical connectors from the fans. There is also a clip that holds one of the AC lines to the fan shroud, unbolt the 2 bolts that secure the fan shroud to the radiator then you can move the fan shroud back about 1/2" on the bottom and slide to the left and up and then to the right and up to remove the cooling fans this takes about an hour and all you need is a 10mm socket on your rachet, a small screw driver and a 7/8 flare wrench for the oil cooler lines (an open end may do, but I prefer a flare wrench). Disconnect the + battery cable and remove the serpetine belt. Disconnect the wires and cooling lines from the alternator and unbolt the alternator, the small snap in connector may be easier to disconnect once the atlernator is unbolted. You do not need to remove the radiator, or the lower plastic shield, or the one in the wheel well, just remove the other end of the upper radiator hose from the engine and slide the alternator to the right and out behind the upper frame member where you removed the air cleaner top. Reassembly is pretty much the reverse. Do replace all of the rubber hoses, you do not want to do this again. Molded hoses are no longer available from Cadillac, so get 3/8 cooling hose as close to the same od as the origional, because the spring clamps are far superior to the worm drive style. Also replace the the O rings on the oil cooler lines, these are available from Cadillac for under $2 ea. Make sure the old O rings are not still in the radiator or they will leak. Although I do not know when changes were made, it could have been any time between mid 1998 and 2000. On a 2000 it is not necessary to remove any transaxle or oil cooling lines. There is no clamp for the oil cooler lines. Remove the upper radiator cover, then remove the hood latch frame and set on top of the engine. Remove headlights, unbolt the 2 bolts from the AC condenser that hold it to the radiator, and lift it clear. Remove upper air cleaner pc. Unbolt the upper transaxle cooler line retainer from the fan shroud and the upper 2 radiator retaining bolts and brackets.and lift up on the radiator and tilt it forward. Remove the 2 radiator hoses from the radiator. Unbolt the 2 bolts that secure the fan shroud to the radiator, and the electrical connectors from the fans. Now you can pull the fan assembly straight up and out, this was a great improvement over earlier models. then remove and repace alternator as on 1998. and reinstall radiator, headlights etc. estimated time for 1998 3-4 hours total. 2000 2-3 hrs total.