1970 (and other years) Cadillac 472/500 water pump

[Scot Minesinger]

Had to replace my inferior water pump on 1970 Cadillac SDV that did not even have 1,000 miles on it, bearings failed.

So the water pump sold to me a few years ago as a replacement did not fit and had to buy another that did and now I'm on the road again.  The one that did not fit sure looked correct but the clearance for the compressor/ps pump was about a 1/4" shy, and would have had to remove the belt closest to firewall to make it work (if I was limping home).  I'm thinking that maybe the one I had would fit the single belt compressor/ps pump set up.  The one that did not fit definitely had a lower section on intake to accommodate a belt, so given that Cadillac was the only manufacturer to compressor on intake manifold, it has got to be a 472/500/425/368 water pump it would seem.

Pump casting number that did fit:  PH-240

Pump casting number that did NOT fit:  1602789Y with "D1" underneath the "89"


Will the pump that does not fit a 1970 Cadillac fit the 74 - 76 or newer Cadillacs?  If I don't find out, will have to discard.

Thanks,

Scot



Here are the casting numbers:

[mikanystrom]

Sorry to hijack your thread but when you say "the clearance for the compressor/ps pump was about a 1/4" shy" you mean the clearance to the BELT, right?

This is very interesting to me.  I have removed the rearmost belt on my '68 Eldorado because it was rubbing against the water pump.  I thought this was caused by a hack job some previous owner did.  You see the 1968s had an AIR pump that most people have ripped out, but said AIR pump was part of the belt routing, so on my car they rearranged the pulleys on VARIOUS accessories (and welded a "special bracket" out of what looks like junk they found in a garbage can at the local junkyard).  I always thought that was the reason I was rubbing, not that I have the wrong water pump!

Where did you get the PH-240 pump from?

[TJ Hopland]

Belt clearance appears to have been the reason for 2 different original part numbers.    I have never seen one that had the high spot before.  Guessing that the reman people (and maybe even AC Delco eventually?) just thought it was easier to only deal with one part so they just got rid of the ones with the high spot so it didn't matter which vintage you were putting it on.

["Cadillac Kid" Greg Surfas 15364]

Unless that "non fitting" pump is some kind of off-breed it sounds like you have a later model (74-78 pump that the single belt and pulley will clear.  That said I would do a trial mok up before calling it so.
Greg Surfas

[Scot Minesinger]

Thanks, it does seem like I got a 74-78 water pump, and will mock up before installing when the time comes.  And yes talking about dual belts interfering with pump.