328 Water Pump - Rebuild or Replace?

Unlikely its the 1st waterpump. If it is the proper design pump (there have been many) for a 328 I'd rebuild it using a late single piece seal.

When reinstalling coat the 8mm bolts with antisieze and use a torque wrench on them and don't tighten over 15 lbs.

 

Like Brian I am partial to the concept of rebuilding it using a more modern single piece seal.

Please note that I have nothing against Nick Forza's water pump. It looks incredibly well built with a robust integrated shaft/bearing set up as is used in later Ferrari pumps like the 355, 456, and 550. That stated, it is my opinion that you can achieve similar reliability at significantly less cost by rebuilding with high quality C3 rated bearings and a single piece seal.

After a frustrating experience with a water pump rebuilder frequently referenced on this forum I followed the lead of Fchat member Martin308GTB and rebuilt my 328 pump on my own using the single piece seal method. That was 10 years ago and it has worked flawlessly without leaks ever since. I have rebuilt about 30 or so of these pumps over the years and the only failure that I'm aware of was in a pump that suffered a cracked seal after the individual performed a 'dry run' with the pump installed and no coolant. Note that with the newer version single piece ceramic seals it is important for the seal to be exposed to coolant when the water pump shaft is in motion for any significant period of time.

Martin308GTB's experience is documented here: 308 w/pump altering design old to new | FerrariChat. In this write up you see that Martin had to do some significant modifications to the water pump housing and the seal seat on the shaft to fit the single piece seal. The later versions of the water pump have the correct ID/OD seal seat dimensions such that modifications are not needed with the exception of the backside of the impeller. After working on many of these pumps I have discovered a little trick to tell if the pump housing is a later version or earlier version without having to disassemble the pump. Looking at the photo provided I highly suspect that this pump housing and shaft would need modification to fit the single piece seal, however, I am not 100% certain. It's hard to do with the pump installed but if you can provide a photo of the weep holes straight on (i.e. not at an angle) I can tell you with more certainty.

 

For those that might be interested I have one of my rebuilt water pumps for sale here: For Sale - 3x8/Mondial Water Pump for sale | FerrariChat. I have a box of old water pump housings that I have collected over the years and when I have some free time I pull one out and rebuild it. The aluminum housing and brass impeller are vapor honed prior to rebuild. The finish of the housing comes out so much nicer compared to sand blasting or painting.

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A big reason to change coolant at two years or sooner!
Many people forget to change and old is ugly

 

There are coolants now that really are good for 5 years. Cat ELC and Shell ELC NF.