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300Tdi water pump replacement

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After my trip through a river, the replacement of rotating equipment continues (note shiney alternator also). Removing the serpentine and wiggling the water pump pulley confirmed the source of the rumbling noise. I don't understand how it wasn't leaking with 3mm of movement at the pulley.

In a Hayneson style:

You will need:

10mm & 13mm sockets and ratchet

adjustable spanner

hammer (of course)

angle grinder (in my case)

a sharp knife

Slacken the 3 bolts holding the pulley to the power steering pump and water pump (you need both). Do this now to save you refitting the serpentine. Then use the adjustable spanner to take the tension off the belt and remove that too. I can't remember why I removed the serpentine tensioner (13mm socket needed) but it made sense at the time. Pull the three bolts to remove the water pump pulley:


and the PAS pump pulley:


Undo the bolts holding the water pump to the front of the engine. Make sure you place a bucket under the car, even though none of your coolant will end up in it - sods law says it'll run along edges, down bars and pipes and leave the bucket bone dry. Be aware that the bolts for the water pump are different lengths - for those who have muddled these up, here's the layout:


Use the sharp knife to scrape off the remains of the old gasket:


The design of my new and old pumps is different, I suspect the new one is a pattern part.


I had a problem with the casting - it was rough and a little thicker than the old one, so the bolt + coolant pipe bracket here was thick enough that the bolt head fouled on the pulley when it was bolted up. After 30 mins attention from a square person I'm not that keen on( :unsure: ) I gave up and introduced my Indian friend, Mr Agrinder. I've removed the coolant pipes to improve access for the sparky spanner - if the pulley on your pump spins ok when installed then it's not necessary.


And plenty of clearance afterwards.


Top up the coolant with your favourite flavour of antifreeze and go for a thrap to check for leaks. Then, if you're me, spend 5 hours in the next two days on the motorway snatching the radio onto mute whenever you hear an odd noise. I wonder how long this one will last...?

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Guest diesel_jim

Good write up. Having just done the same on my 300 90,i'd like to add the following:

you needed to remove the belt tensioner so that you could get the top corner bolt out of the water pump.

and the factory method for re-filling the water (which really seems to work well at getting air locks out) is:

remove the filler bung thing on the thermostat housing, fill the system through the header tank until water starts to come out of the thermostat housing (you need to fill it gently, in little amounts, as it takes several seconds for the water to settle and fill all the water-ways in the engine... that or my watre is too thick!! :unsure: )

then refit the filler plug, and then add another 1 litre of water to the header tank.

start the engine and allow to idle for 5 minutes.

I did this on mine and when i re-checked the water level, it was spot on!

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Aye.... a good honest account of what REALLY happens... Well done! :)

When I did mine I started loosing water again pretty soon. Turned out it was the P gasket that hadn't sealed again after taking out then 3 long bolts. So I had to do the whole job again :rolleyes:

So now whenever somebody asks me whats involved, I tell 'em to do the P gasket at the same time.

Dan :D

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