A pictorial guide #
Water pump replacement on the VR6 is not as straightforward as on some other cars, but it is not as horrific a job as the Bentley manual might make you think - if you're careful, you can do it without any major disassembly and without any particularly special tools. Hopefully this guide will tell you everything you need to know, but please tell me if anything is unclear.
First though, a few notes on why you might want to change the pump. The OE VR6 water pump has plastic vanes, good seals and big bearings. The vanes don't corrode like steel ones would, and if your cooling system has been serviced normally and the engine hasn't been overheated, there should be no reason for the seals or bearings to have failed. Here's a 156000 mile VW pump (left) compared to a new aftermarket one:
As you can see, there is nothing wrong with the rotor even after so many miles, and the bearings and seals were still perfect. Yes, I still changed it just to be sure (chasing a cooling system problem) but it made no difference. Bear that in mind before you start taking your car to bits!
Things you will need: #
* Water pump (£30 from GSF at the time of writing, if memory serves)
* Water pump seal o-ring (should come with the pump, but mine didn't!)
* 18mm and 19mm 1/2" drive sockets
* Ratchet, long and short extensions, and a universal joint in 1/2" drive
* 13mm and 10mm 3/8" drive sockets
* Ratchet and short extension in 3/8" drive
* 6mm allen key - having both normal and 3/8" drive types is handy
* M8 bolt, at least 1.5" long
* Trolley jack
* Bit of wood
* 3L G12+ coolant and 4.5L water (preferably de-ionised or RO) to refill
The Bentley manual would have you believe that you have to remove lots of hoses, the exhaust and all the engine mounts, then lift the engine up from above with a crane and a special load leveller. This thankfully is overkill, and can be done with only the following actions:
Remove stuff that gets in the way #
Take the hose clip off the engine side of the MAF, and remove the airbox (unclip the top half from the bottom half and remove it, and you can then get to the rubber bands that hold the bottom half to the car).
Unplug the radiator fans, and remove the small tube on the breather (near the throttle body) as shown (mine is still connected in the picture, and you can see that it's just a little too tight for comfort).
Disconnect fan plug
Breather tube, airbox gone
Remove the tin plate that covers the rear engine mount - you'll need the 3.8" ratchet, a short extension, and the 13mm socket. Tuck the plate out of the way when you've got the nut off, somewhere where it won't catch between engine and car later on.
Now is a good time to drain the coolant if you haven't already, as you'll soon have less room to get a bowl underneath the car. Take the cap off the header tank before you remove the plug on the crack pipe. Usual warnings apply about taking the cap off if the engine is hot...
Undo engine mount bolts #
As you can see in this picture, the water pump sits well below the top of the chassis leg. In order to be able to undo the bolts and get the pump out, that side of the engine needs to come up about 5"...
Pump in normal position
In order to be able to lift the engine, the two engine mounts need to be completely unbolted, and the gearbox mount needs to be loosened. Some suggest that you don't need to remove the rear engine mount, but if you don't the crank pulley hits the chassis leg and prevents the engine coming up far enough - this is as far as it goes with the rear mount bolt still in, clearly not far enough to get the pump out of the block:
Pump in half-way position
The mount bolts are well hidden, so you'll need all the 1/2" drive tools chained together. The engine-side bolts are 18mm, and inexplicably the gearbox-side one is 19mm. Only undo the gearbox one about 3 turns, as that side of the engine can stay low. Sadly I don't have a photo of the gearbox mount bolt (which is by far the most awkward - put the UJ on the bottom of the extension), but here's the other two:
Remove bolt from rear mount
Remove bolt from front mount
Jack engine up #
The engine is now free to move upwards on the pump side. Get your trolley jack and bit of wood, and position it right on the front corner of the sump on the pump end of the engine:
Jack in place
Jack the engine up until all the pump bolts (3 on the pulley, 3 holding the pump to the block) are accessible. The exhaust will set the upper limit, so when it hits up against the tunnel stop jacking:
Pump in access position
Gap on rear mount
Gap on front mount
Exhaust in contact with tunnel
Remove pulley, belt, and pump #
The first thing you should do is crack the pulley to pump bolts off, whilst the belt is still tensioned. Use the 6mm allen key, and just undo them half a turn. Then, take your M8 bolt, screw it into the threaded hole in the tensioner, and wind it in until the belt is loose:
Wind bolt into tensioner
Wind bolt into tensioner
You can then unscrew the pulley bolts all the way, and remove the pulley from the pump. Using the same 6mm allen key, remove the three bolts that hold the pump into the block, and remove the pump. Check that there's no obvious signs of nastyness in the block with a mirror or camera:
Hole in block with end of crack pipe just visible
Fit new pump and o-ring seal, refit pulley and belt #
The manual says you don't need any sealant on this joint (how nice of it), but I didn't have a new o-ring so I clarted it up with Red Hermetite - doesn't seem to leak! Do the bolts up nice and tight, you don't want the pump shuffling around when you put the belt tension back on.
New pump installed
Replace the pulley (nip the bolts up, but you can't put any torque on them yet), put the belt back on, unscrew the M8 bolt from the tensioner, and then put the final torque on the pulley bolts.
Lower engine and bolt mounts back up
Carefully and slowly lower the engine on the jack until the two bolt-less mounts *just* touch their counterparts - this will make it much easier to get the bolts back in! Fit the bolts finger-tight, and then lower the engine all the way and remove the jack. Torque all three mount bolts up good and proper.
Refit fiddly parts #
Refit breather pipe, fan connector, the tin plate off the rear mount, and the airbox. Make sure you get a good seal on the pipe to the MAF.
Refill with coolant, and perform sanity check #
Refill with the prescribed 40:60 mix of G12+:water via the top radiator hose, using just shy of 7.5L of mixture in total. You remembered to put the drain plug back in the crack pipe, right? Got wet shoes? No? Good. Refit header tank cap, and make sure no water is pouring out anywhere. Now, sanity check:
Engine full of coolant?
Fan connector back on?
All hose clips in place?
All tools accounted for?
Oil level okay? We didn't touch that, but check it anyway...
Gearbox in neutral?
Alles klar? Gut. Start the engine and let it get up to temperature, keeping a close eye on the temperature gauges. Let the radiator fans come on (should happen by 100°C), then shut the engine down. Get a light and crawl all round under the car to make sure the coolant isn't leaking out of anywhere - watch out for the hot bits, mind.
Take it for a spin! #
Keep an eye on the gauges and be paranoid about coolant level for the next few miles, just for peace of mind and to make sure you don't have a rather more hefty repair bill in the future. If everything checks out, go back to thrashing the crap out of your lovely VR6!