HOW DO I TIGHTEN THE LOOSE BELT AFTER INSTALLATION ON 97 BUICK LE SABRE? REALLY NEED A DIAGRAM TO MAKE SURE I INSTALLED THE SERPENTINE BELT CORRECTLY.

here it is

The dealer cost is about 475 and a shop cost is 385 and do it yourself is 106,since your getting other work done means it sounds fair,3 hours to do water pump.Here's a link on doing the water pump. Repair Guides Engine Mechanical Water Pump AutoZone com here's the water pump. Water Pump 1998 Buick Lesabre 6 Cylinders 3 8L SFI OHV AutoZone com plus a gallon of extended life antifreeze full strength.And a tube of sealant and gasket.

The belt has an automatic tensioner pulley and no other adjustment is needed or provided for. If the belt is to loose you either have the wrong belt installed or the automatic tensioner is defective.

There should be a belt diagram under the hood on your fan shrowd if not a repair manual. Good Luck

These were a real pain in the neck to change, you may want to take it to a shop if you don't have a lot of experience. The hassle of doing it yourself may outweigh the cost.
Here's the procedure, but it is easier said than done:

REMOVAL

1. Remove the following components.

1. The engine mounting bracket lower nut.
2. The engine mounting bracket lower stud.
3. The engine mounting bracket lower spacer.

1. Remove the belt.

INSTALLATION

1. Install the belt. Refer to Engine Mount in order to install the following components:

• The engine mounting bracket lower nut.
• The engine mounting bracket lower stud.
• The engine mounting bracket lower spacer.

You don't have to remove the mount. Go thru the wheel well on the passenger side and remove the motor mount bolt just right of the crank pulley. Then remove the stud that the nut was on. Then remove the sleeve that the stud goes thru. Then you can change the belt.

Since there is NO sticker under the hood of this 2003 Buick LeSabre and it is not in the owner's manual, a Google search revealed that it is the same as at http://www.fixya.com/cars/t3438653-change_serpentine_belt_1998_buick

need to see diagram for serpentine belt installation on 19991 buick lasabre

those wires are probably going down to the crank sensor if that sensor fails then the car will not start so fix the wiring and try replacing the crank sensor.

Yes, I have a 97 buick and the motor mount does have to be removed. See information below that I retireved from Autozone.com:

REMOVAL & INSTALLATION
See Figures 7 through 13

1. Disconnect the negative battery cable.

Fig. 7: Many vehicles have an accessory drive belt routing label affixed to the radiator shroud

1. Remove the belt guard or coolant recovery reservoir as required.
2. For 1996-99 supercharged engines, perform the following:
   1. Raise and safely support the vehicle.
   2. Remove the right-hand splash shield.
   3. Remove the connector from the crank sensor.
3. For 1996-99 vehicles, remove the engine mounting bracket lower nut, stud and spacer. Carefully lower the vehicle.