1999 Jaguar XJ8 Water Pump / Thermostat Replacement

IANWOD

MEMBER
1999 JAGUAR XJ8

Engine Cooling problem
1999 Jaguar XJ8 V8 Automatic 48000 miles

I recently purchased a '99 Jaguar Vanden Plas with 48000 miles on it. I am planning on replacing the secondary tensioners, water pump, and thermostat this weekend as I have read those parts have a history of failing with this car. I have been able to find a detailed guide to replacing the tensioners, but cannot seem to find any regarding the water pump and thermostat replacement. I was wondering where exactly the pump and thermostat are located and what would be involved in replacing them. This car is very new to me (upgraded from a '93 geo storm) and I don't want to do any repairs without specific instructions.

1 Reply

DAVE H

EXPERT

THERMOSTAT
Removal (Non-Supercharged)
Open the engine compartment hood to service position and install body protection covers. Carefully remove the engine covers, taking care not to damage the plastic retainers or the rubber inserts.
Drain the cooling system. See COOLING SYSTEM. Retain the coolant drain tray in position to catch any spillage when removing the thermostat cover.
Loosen and reposition the lower hose clamp. Remove the lower hose from the thermostat cover. See Fig. 186.
Remove the 3 thermostat cover bolts and remove the thermostat cover from the housing. See Fig. 187.
Remove the thermostat from the housing and discard the seal. See Fig. 188.
Installation
Install a NEW seal to the thermostat. Install the thermostat so that the vent ball valve locates in the recess in the cover. See Fig. 188.
Install the thermostat cover and the 3 thermostat cover bolts. Tighten thermostat cover bolts to specification. See TORQUE SPECIFICATIONS. See Fig. 187.
Install the lower radiator hose to the thermostat cover. Reposition hose clamp to secure hose. See Fig. 186.
Carefully install the engine covers, taking care not to damage the plastic retainers or the rubber inserts.
Refill cooling system. See COOLING SYSTEM.
Check for leaks and that all coolant hoses are securely connected. Move the engine compartment hood from the service position and connect the gas struts. Remove the body protection covers and close the engine compartment.
Fig. 186: Removing & Installing Lower Radiator Hose At Thermostat Cover (Non-Supercharged)
Courtesy of JAGUAR CARS, INC.
Fig. 187: Removing & Installing Thermostat Cover Bolts (Non-Supercharged)
Courtesy of JAGUAR CARS, INC.
Fig. 188: Removing & Installing Thermostat (Non-Supercharged)
Courtesy of JAGUAR CARS, INC.
Removal (Supercharged)
Open the engine compartment hood to service position and install body protection covers.
Drain the cooling system. See COOLING SYSTEM. Retain the coolant drain tray in position to catch any spillage when removing the thermostat cover.
Loosen and reposition the lower hose clamp. Remove the lower hose from the thermostat cover. See Fig. 189.
Remove the 3 thermostat cover bolts and remove the thermostat cover from the outlet pipe. Remove the thermostat and the seal from the outlet pipe. Discard the seal. See Fig. 190.
Installation
Install a NEW seal to the thermostat. Install the thermostat so that the vent ball valve locates in the recess in the cover. See Fig. 190.
Install the thermostat cover and the 3 thermostat cover bolts. Tighten thermostat cover bolts to specification. See TORQUE SPECIFICATIONS.
Install the lower radiator hose to the thermostat cover. Reposition hose clamp to secure hose. See Fig. 189.
Refill cooling system. See COOLING SYSTEM.
Check for leaks and that all coolant hoses are securely connected. Move the engine compartment hood from the service position and connect the gas struts. Remove the body protection covers and close the engine compartment.
Fig. 189: Removing & Installing Lower Radiator Hose At Thermostat Cover (Supercharged)
Courtesy of JAGUAR CARS, INC.
Fig. 190: Removing & Installing Thermostat (Supercharged)
Courtesy of JAGUAR CARS, INC.
WATER PUMP
Removal
Open the engine compartment hood to service position and install body protection covers.
Drain the cooling system. See COOLING SYSTEM.
If equipped with a supercharger, remove supercharger drive belt by fitting a 1/2 inch square drive ratchet or bar into square opening on front face of tensioner. Rotate tensioner assembly to the right (viewed from front) against spring tension. While holding the tensioner against spring tension, remove supercharger drive belt from tensioner pulley. Release tensioner slowly and remove bar. Disconnect supercharger drive belt from other pulleys and remove it from rear of tensioner. See Fig. 100.
On all models, loosen the 3 bolts which secure the water pump pulley. Using a spanner wrench on the center bolt of the belt tensioner idler pulley (Churchill JD-230 or Snap On XDHM 1415), turn the adjuster assembly to the left against spring tension. While holding the tensioner against spring tension, remove the drive belt from the generator pulley. Release the tensioner slowly and remove the spanner wrench. Remove belt from all other pulleys. Remove the 3 screws from the water pump pulley and remove the pulley from the water pump. See Fig. 146.
Remove the 5 water pump bolts and remove water pump from the engine. Remove and discard the water pump gasket and "O" ring. See Fig. 191.
Clean any coolant spillage from the engine compartment. Clean all parts and sealing faces.
Installation
Using a NEW water pump gasket and "O" ring, align and install water pump. Install the 5 water pump bolts and tighten to specification. See TORQUE SPECIFICATIONS. See Fig. 191.
Install the following:
Water pump pulley and 3 water pump pulley bolts. Tighten bolts after drive belt is installed.
Drive belt around all pulleys except the generator. Using a spanner wrench on the center bolt of the belt tensioner idler pulley (Churchill JD-230 or Snap On XDHM 1415), turn the adjuster assembly to the left against spring tension. While holding the tensioner against spring tension, install the drive belt around the generator pulley. Release the tensioner slowly and remove the spanner wrench.
Tighten all fasteners to specification. See TORQUE SPECIFICATIONS. See Fig. 146.
NOTE:Ensure that supercharger drive belt is correctly and squarely located on each pulley. Check belt wear indicator marks to confirm that supercharger drive belt is within limits. See Fig. 102.

If equipped with a supercharger, install supercharger drive belt to all pulleys, except tensioner pulley. Using a 1/2 inch square drive ratchet or bar into square opening on front face of tensioner. Rotate tensioner assembly to the right (viewed from front) against spring tension. While holding the tensioner against spring tension, install supercharger drive belt to tensioner pulley. Release tensioner slowly and remove bar. See Fig. 100.
On all models, refill the cooling system. See COOLING SYSTEM.
Check for leaks and that all coolant hoses are securely connected. Move the engine compartment hood from the service position and connect the gas struts. Remove the body protection covers and close the engine compartment.