Thread: 300tdi water pump gone again - HELP!

Have had similar problems with large diesel engine used to generate power. Turned out to be the radiator cap holding vacuume on system when the engine was shut down the engine water cooled and the radiator cap did not allow water back from expansion tank causing the system to be under a vacuume. We changed the radiator cap and it worked fine.
Hope it helps.
Frank.

Thanks Gippslander...I did replace the radiator cap in September last year. I guess it could be faulty - will check it out.



Andrew

Make sure the fan belt tensioner is straight.When they wear out,if it's the original it would be they lean forward putting strain on the pump bearing.Take the belt off and feel for movement in both the idler bearing and tensioner arm. Pat

The recommendations of Gipps & Pat are both quite relevent... and I know you say it's coming from the hole at 6 o'clock, but while you're at it make sure you get a torch and look behind the housing where the "P" gasket resides (between the housing & the block) - an additional annoyingly vulnerable point for weeps etc

... and did you flush the coolant system each time you replaced a pump ?

but then again it can just be bad luck

Originally Posted by PAT303

Make sure the fan belt tensioner is straight.When they wear out,if it's the original it would be they lean forward putting strain on the pump bearing.Take the belt off and feel for movement in both the idler bearing and tensioner arm. Pat

I'm well aware that they do eventually wear out of line but I'm not quite sure how you determine if it has done so - do you rely on chirping/squeaking from the serp belt to identify this ??

Hi all
I believe the previous owner replaced the tensioner (from the records I have) so it is not the original.

The tensioner feels ok with zero bearing noises and the tension feels ok (not overly hard) when removing the belt.

P gasket was replaced in September last year with no leaking since. Weep is from the hole at 6 o'clock below the water pump shaft.

Cheers
Andrew

Originally Posted by 87County

I'm well aware that they do eventually wear out of line but I'm not quite sure how you determine if it has done so - do you rely on chirping/squeaking from the serp belt to identify this ??

The best way is to see if there is a gap at the top,if the mount and arm are touching quite often you'll see a sliver of alloy where the two are touching and if so it's U/S.With the bearing if it's squeaking it's not aways the bearing failing,it can be the dust cover rubbing on it. Pat

One of the OE pumps is made in Spain (Airtec or something like that ?) and seems fine as far as quality goes.

At one stage it used a cast impeller but now have gone back to a pressed steel one.

[edit] the pump is an Airtex, and my frigging P gasket started leaking about four months after the pump change mentioned in that thread Is there a H/duty water pump for 300Tdi's ????P Gasket!