Water Pump Failure

[thebawse]

Hi guys.

On the weekend I did the cam belt, tensioners + water pump on my gts25t with brand new 'genuine' Nissan parts. All went smoothly and the car was running fine till this afternoon + a bit of 'spirited' driving caused this:

The crack runs about 240degrees around the shaft and there is a chip out of it as you can see.

My question is obvious, WHY?

Was my alternator belt so tight it caused this? I didn't use a belt tensioner but I know it wasn't overly tight and the belt is in good condition as is the alternator pulley.

Or was the water pump a faulty product? Can anyone confirm if it is 'genuine' based on this number?

I just want to get a heads up before I go back to the seller.

[89CAL]

How tight did you do the bolts up?

Are you sure it wasn't to tight? have seen this failure before. Can't remember exactly but think it was overtight belt

[Ben C34]

My correctly tightened belt and your tightened belt could be two different things, and I suspect you have gone way too tight.

To give us an idea, how much mechanical experience would you have?

[thebawse]

Water pump bolts were torqued to spec. The belt wasn't tensioned as I don't have a belt tensioner, but I was able to give the belt a 1/4 turn on the top and bottom.

It took less than 30kms for this to happen.

Would it have a chip out of it like that if the belt was over tight?

I'd classify myself as an 'advanced' DIYer. First time doing a cam belt change but not the first time dealing with auxiliary belts.

[Ben C34]

Thanks, that puts it in perspective. Some guys have absolutely no clue and do things up mega tight.

personally I always err on the side of loose, as you will know if it's too loose (it squeals) but too tight is harder to know.

I don't think many people use a tension gauge.

The thing is as you would know if you are super strong you can get a quarter turn on pretty much any belt no matter how tight it is. Have you been working out lately

[89CAL]

hmmm that makes it interesting then

why did you put quotation marks around genuine? Was it not from a completely reliable place or second hand or something along those lines?

That might be my only concern now. If bolts were done up right, and sounds like the tension was O.K (without knowing how hard you were turning it to get 1/4 of a turn)

I have my own 1/4 of a turn method that I've been doing for quite a while now on alot of different belts (heavy machinery mostly) and usually is pretty good on your standard v-belts. But as said, I've been doing it my way for years with no issues, but your way and my way might be the same in theory but completely different lol.

[thebawse]

Haha, that's a definite no on the working out! My arms got tired after just doing this job.

The parts were from a Nissan dealer, more specifically from here:

http://www.trademe.co.nz/Browse/Listing.aspx?id=715037326

I put quotes around genuine as the cam belt came in a package labelled 'A31 RB20DE' and the water pump is marked '3Y07' which is different from the old one. I know neither of these things are necessarily bad and they might both be genuine and correct parts for an RB25 so hopefully one of you guys can confirm this for me so I can put that one to rest?

[jiffo]

When you stripped it down to inspect the damage, was the alternator belt still sitting properly in the various pulley grooves?

Hadn't tried to climb off or anything?

I have seen pumps go like this previously, but they were no-names.

If you break the pump right through at that crack I think you'll be amazed how thin the metal is.

[thebawse]

When you stripped it down to inspect the damage, was the alternator belt still sitting properly in the various pulley grooves?

Hadn't tried to climb off or anything?

I have seen pumps go like this previously, but they were no-names.

If you break the pump right through at that crack I think you'll be amazed how thin the metal is.

Yeah mate all belts were in line and are undamaged, no nicks out of them or any cracks.

Comparing the old pump with the new, the new one does seem to be a bit lighter and not of the same quality. That could be my imagination telling me what I want to hear though.

[BlackBox]

Saw this failure on my mates Mazda after we put a new wp on, we went with manufacturing defect but would be interested in other thoughts. (Mechanic by trade so I'm confident in the workmanship )

[thebawse]

Saw this failure on my mates Mazda after we put a new wp on, we went with manufacturing defect but would be interested in other thoughts. (Mechanic by trade so I'm confident in the workmanship )

I'm sending it back to the Nissan dealer for them to have a look. I'll let you know what they say.