my battery warning light came on at the start of a trip recently and was accompanied by a burning smell under the bonnet. At idle a voltmeter across the battery terminals indicated a puny 11.2 volts so it was all pointing to a failed alternator.
The only warning sign had been a slight whirring just audible at idle if the radio was off and I first noticed that several weeks earlier.
The best price I could find for a brand new replacement genuine Denso was site sponsor Advanced Factors at £210.90 delivered free within 24 hours and I even got a free coffee mug with it. Just make sure you order the correct variant which is Denso reference DAN990.
Special tools that are nice to have but not essential for this job are:
Three ton trolley jack
Six ton axle stands
Viscous fan removal tools
Hose clamp
Hose clip driver
1/4 , 3/8 and 1/2 drive socket sets
Torx driver set
1/2 drive breaker bar
Polytubing
Clean plastic container.
and in my case a beer crate to stand on so I could see into the engine bay with the car jacked up!
You may also need some engine coolant which seems to be only available from Land Rover.
First job is to jack up the offside front wheel using the jacking point on the chassis and remove the road wheel. Chock the wheels and position axle stands.
Remove the mud flap if fitted followed by the wheel arch liner and front splitter.
You will then be able to see the alternator:
Next job is to remove the upper cowling from the radiator fan and this entails disconnecting the RH turbo boost pipe and small coolant hose in order to make room for the cowling to come out. I clamped the hose and plugged the radiator union with a bit of plastic sheet stuffed with a cloth:
A small amount of coolant might be lost at this stage. Once you have the cowling off re-connect the hose to minimise any further loss of coolant.
Next remove two MAFF sensors from the airbox, remove the air box lid, air filter and after removing the small internal torx bolt, remove the airbox tube and airbox. The airbox needs a good tug as it is mounted in rubber inserts underneath.
Disconnect the wiring to the viscous fan and using the special tools if you have them remove the fan by using one tool to immobilise the coupling nearest the engine block and the other to undo the LH threaded fan. I found the fan came off VERY easily so the special tools were really not needed. Could easily have wedged the coupling with a 10mm spanner and used a big adjustable wrench.
Special tools:
Hold back the drive belt tensioner using the socket (21mm I think?) and breaker bar and carefully remove the drive belt from the alternator. Ideally get a helper to handle the breaker bar as you don't want to slip and trap a finger in the belt.
I've subsequently been told that removing the fan isn't essential as you can reach through the fan to access the tensioner but since my fan came off so easily it wasn't an issue.
From inside the wheelarch remove the alternator electrical connectors (one plug and one +ve lead) and loosen the rearmost turbo downpipe hose clip and remove the pipe by twisting and pulling up from the engine compartment.
This next bit was crucial - there is a turbo pipe running horizontally closely below the alternator. Locate and remove the nut holding this pipe onto a stud welded onto the chassis. It is hard to reach and a long 10mm ratchet spanner was almost essential. When the nut is off pull the pipe off the stud and push it downward - it won't go very far but the extra few millimetres is vital so you can get a 3/8 drive 13mm socket onto the two lower bolts securing the alternator. Just use the socket to loosen the bolts and then remove them using fingers and/or a combination spanner.
The remaining upper bolt can be removed with a 13mm combination spanner.
Juggle the alternator into the right orientation and it will just come out through the wheelarch.
Fitting the new alternator I found was only possible once the upper mounting was opened up by partially pressing out the bush on the mounting using the time-honoured technique to press out bushes of a bolt, washer, nut and socket:
Then it is just a case of reassembling everything. Take care to ensure the airbox is fully down on the rubber inserts - it is easy to think it is when it's not.
Run up the engine and the battery light should extinguish itself after a few seconds. Use a diagnostic tool on the OBD port or connect a multimeter to the battery to check you are getting a healthy 14 volts or more.
When all is back together the coolant system should be bled. The last time I did this it was very messy as the bleed screw on top of the expansion tank allows coolant to go everywhere. This time I found a length of poly tubing that fitted nicely into the bleed screw hole and could be screwed in tightly on the threads and led to a clean container positioned to catch the fluid that is driven out when you rev up the engine for several minutes at a time.
From inside the car you get a good view of air bubbles going up and out of the tube. After you have bled the system some coolant will have come out into the container and it can be returned to the expansion tank if clean and uncontaminated.
To complete the job properly clean the engine bay with degreaser, scrubbed in with a paintbrush, hose off with a low pressure garden hose (keep it well away from the area behind the battery where the ECUs are), spray with Autoglym vinyl and rubber cleaner and towel dry for a spotless shine.
All very satisfying - knowing the job is done properly with every clip, screw, bolt and fixings unbroken and back in the right place. And all for a couple of hundred pounds. If you have the time no doubt the old alternator could be fitted with new bearings, brushes, slip rings and rectifier pack using a kit that can be bought for around £50 from specialists.2008 MY Java Black TDV8 HSE
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Fri Jun 02 2017 4:35pm
