Water Pump 3.8

[richard btype]

I fitted a new water pump a few days ago but noticed the impeller shaft was uncomfortable on rotation for example in comparing to a clock, the movement would be free from 12 to 10 and the last ten minutes was decidedly rough/sticky/catching like a bearing that is breaking down.

I rang the supplier who said this was normal and under use would free up!

Have just returned from a 12 mile spin and the noise is now transmitting into a light engine nock and worse now than at the beginning of the journey, certainly does not feel like it is going improve, has anyone else experienced this?

[cactusman]

No....but snaggy bearings rarely improve with use....methinks the supplier was fobing you off. Afraid I would whip off pronto and return and demand a full refund as the consumer rights act entitles you to. New bearings don't snag.

[richard btype]

Julian

I spoke with the supplier this morning but no one on the desk who could help, we'll speak again on Monday when technical staff are in, but I agree with your comments...

[PeterCrespin]

Did it spin freely before fitting? Maybe the impeller doesn't match the timing cover and is binding. If you take it off, spin it before returning. The impeller may also just touch the pump body and this probably would clear up if it de-burrs the casting.

[richard btype]

I contacted the supplier and they have frozen their stock subject to an inspection and therefore awaiting a pre checked replacement.

Just for the record Peter I did notice the binding problem before installing so it is related directly to the pump (possibly casing) and not the timing cover. Unfortunately no 'de burring' occurred during a 12/15 mile drive...

[christopher storey]

Richard : your pump sounds defective. I just fitted a new one to my Cooper S and was surprised at how stiff to turn compared with the old one the impeller was , but the stiffness was absolutely uniform and smooth as silkl

[Robert Hiland]

You may wish to purchase a new one from XK's Unlimited.

They now manufacture their own water pumps. I bought one about 3 years ago. I could be my imagination but the car runs cooler now.

Excellent product. Read all about it in their website.

No core return required.

One note of caution however ... the new pump with the pulley does not fit through the picture frame (too large by about 1/4").
Install without the pulley and then then attach the pulley.

Bob

[andrewh]

I had exactly this and discovered it to be the casting mark on the new pump fouled the pulley. Easily solved by removing the pulley and grinding the casting number down with a dremel or die grinder. Worth looking

Andrew

[richard btype]

This is all very annoying and completely avoidable with just a little quality control and thought - I mean just how difficult must it be for the assembly guy to test the smooth spin of a the impeller shaft to determine an issue or not?

Following a frustrating week awaiting promised phone calls (3times) and hearing nothing, I had to become rather vocal. This had the desired effect, and I insisted they first check their stock before sending a replacement. This duly arrived Friday and the replacement had no rotation problem what so ever.

It is no big deal fitting a new pump (2 hours work) but not something you would choose to do twice! So set to last evening by draining down the system. After loosening the dynamo (yes really, no alt. upgrade). During removal of the belt I noticed the pulley was actually loose on the impeller plate i.e. the four fixing bolts were not fully at home, and I really gave these special attention during assembly!

So a tip would be to remove the paint from the mating surface and or first bench fix the pulley and then remove it so any mating discrepancy could be addressed (the pulley has to be fitted over the plate in order to install the pump but 'not fixed' with the four bolts - this has to be done as a second operation - as otherwise the long pump mounting bolts will not clear the pulley when mounting to the timing case).

Clearly the 12 mile run had loosened the paint which had caused the pulley not to be fully seated on the pulley plate and hence the knocking sound (only at low revs) for the pulley was now loose and floating around on its four fixings. I'm so pleased this was a very short test drive for had I assumed all was well and been motoring on a long journey, then I'm certain the alloy pulley would have been worn away around the four mounting positions and or the fixings would have snapped off.

There was some damage to the four fixings because in trying to remove them they were extremely tight and had a concern that the bolts would shear, so I tried the other way i.e. to tighten them and there was less resistance although still an effort.

During this operation I then noticed that there was now no resistance in what was considered to be a faulty bearing, so it was not a bearing issue but (probably) the impeller was catching on the casting and the 12 mile run had sorted this out - just as I had been informed by the supplier and mentioned by Peter C.

I will take this up with the supplier because there are 2 simple corrections that could be made,1) no paint should be applied to the pulley mating plate and 2) the impeller de burring should be checked at the factory or alternatively a note should be included to explain.

The way this has turned out has been unnecessarily time consuming, frustrating and potentially a road side break down with destruction of an original alloy pulley not to mention the wasted carriage cost for the replacement pump which now has to be boxed up and returned - all simple stuff that could so easily be avoided...

[andrewh]

A possible reason your pulley was not fully home was because of the casting number on the pump that I referred to. The pulley fits so close to the casting that it rubs on the number. IF you had not spotted that and tightened up the four bolts they would loosen as the pulley wore away the number. Interesting to see whether that had happened.

[richard btype]

The casting number on my pump is well away from the pulley, on reflection the catching was on the impeller side of the pump...

[andrewh]

Ah ok, well just a thought as it was a problem on my replacement pump. Albeit that was for a 4.2, think they are probably the same as a 3.8 though.