Water pump choices. Flange height?

[trev]

Sooooo.....

Getting a squeak and losing some coolant up front on the passenger side. So I'm looking for a new water pump.

Go into the parts place, and they come up with between four and six choices for a pump, depending on the exact year they punch in. You know, working on the vague theory that they are pretty much the same unit for a period of time. Maybe not.

Eight, or nine bolts. That I can crawl under, and count to check.

30mm or 40mm flange height. OK. Measured where?

1990 Jetta TD. No air. What do I need to know to get the correct pump, besides this? I wish to avoid having to order in two or three pumps to get a match for sure. Also trying to avoid having to pull it off and wait a week for the parts to come in.

Metal impellers? Reading about teh plastic impellers falling apart does not make me all warm and fuzzy about them. What's a guy gotta do to get a metal impeller without buying a machine shop to make it?

Thanks for the help!

 Cheers
  Trev

[burn_your_money]

I'm not 100% sure of this but I think the 8 and 9 bolt difference doesn't matter.

30 or 40mm is the hub diameter that the pulley mounts to. Just take a ruler and measure yours. You don't need to be precise, 30 and 40mm are the only sizes.

[trev]

Thanks Tyler!

I'll check my shaft diameter when I crawl under to count bolts.

If I got what the guy was saying correctly, the count matters, as I only get the front half of the pump, rather than the whole assembly.

Any bets on whether the replacement comes with metal or plastic impellers?

Any input, anyone?

Cheers
  Trev

[Rabbit on Roids]

i would bet my left nut it takes a 30 mm hub pump. all my newer cars have small hub pumps, while all the old rabbits have 40mm hubs. i think they quit using the big hub in 82 or something like that. you can swap to a small hub or big hub by using the appropriate water pump pulley.

[rs899]

What RoR said.  It almost has to be a 30mm, if its a 90.  Unless someone swapped it with an oldie.  Nah, that never happens....

Anyway, I think the cutoff was even earlier, like 1980....

[Rabbit on Roids]

yea, im not sure of exact date, but all my diesels have large hubs (cause there old as crap) and all my gassers have small hubs (except my 1980 gas rabbit).

[theman53]

The 9 bolt pump works on the 8 bolt housing. I have done it. Filled the 9th hole with silicone just in case, but had no problems.

[trev]

Awesome info! Thanks Y'all! 

Been putting this off for too long. Gotta get on it!
No idea why they would have so many choices for pumps in the parts book under that year/model. Oh well.

Cheers
 Trev

[trev]

Hey all!

Thought I'd pop a note in here and thank you for the good advice.

9 Hole, 30 mm flange it was.

Changed it out last weekend and have been running without issue since.

Cheers
  Trev

[burn_your_money]

Glad to hear. Thanks for the update.