Auxiliary Drive Belt Replacement
Replacing the tensioner and drive belt is a quick and easy job – here’s how we did it
This 2005 2.7-litre TDV6 Discovery 3 was in the workshop for other work, but when running the engine the mechanic heard a squealing noise from the accessory drive belt, possibly from one of the drive belt tensioner pulleys. An inspection revealed that the accessory drive belt tensioner pulley (also known as an automatic double tensioner) was starting to fail. The tensioner part of the assembly was seized and beginning to crack open, and would fail in a short time, so the tensioner pulley would need to be replaced. It’s also worth replacing the accessory drive belt at the same time, especially considering it may have been damaged by the defective tensioner.
Replacing the tensioner and auxiliary drive belt is a simple and easy job. The hardest part is often removing the cooling fan. This needs a special thin 36 mm spanner (left hand thread), plus either the Land Rover special tool or a similar homemade tool to hold the fan pulley.
1Undo the air pipe from the radiator cowl, then the hose clamps securing the air pipe from the air cleaner housing, and remove the pipe.
2Unclip the header tank pipe from the top of the cowl, then pull the cowl backwards to free it from the radiator and remove it.
3Unclip the wiring multi-plug and disconnect the wiring harness running from the cooling fan assembly to the multi-plug socket on the fan housing.
4Using a suitable tool to prevent the fan pulley from rotating, use a thin 36 mm spanner to loosen the cooling fan from the pulley (left hand thread).
5You can then unscrew the fan from the fan pulley by hand, before removing the fan assembly from the engine bay.
6Once you have removed the coolant fan assembly from the vehicle you can now have access to inspect the tensioner and the accessory drive belt.
7Before removing the old belt, make a diagram or take a photo of the belt’s route around the pulleys, as its easy to forget when fitting the new belt.
8Using a 3/8 inch square socket drive, rotate the tensioner pulley anti-clockwise to release the tension, allowing you to remove the accessory drive belt from all the pulleys.
9Once the belt has been removed, unbolt the securing bolt that is holding the drive belt tensioner to the engine, and remove the tensioner.
10Here is our old tensioner pulley. The unit automatically keeps the accessory drive belt under the correct tension.
11The original automatic drive belt tensioner was seized and starting to break open, as can be seen in the picture, and would obviously soon fail.
12Fit the new belt tensioner into position onto the engine. When it is correctly installed, fit the securing bolt and tighten to 45 Nm.
13Using the 3/8 inch square drive bar, rotate the tensioner anti-clockwise. Holding the tension off will allow you to fit the new accessory drive belt.
14With the new belt in position release the tensioner, this will now tension the new belt. Double check you have fitted the belt correctly.
15The coolant fan is screwed back on to the fan pulley, the radiator cowl clipped in and the header tank pipe attached, and the multi-plug reconnected.
16Finally, refit the air pipe onto the radiator cowl and tighten the hose clips securing it to the air cleaner housing and turbo pipe. Job completed.
Eliminate noise and keep all systems running with a routine auxiliary drive belt replacement