412265-D24 Water Pump

[ray]

Before I purchase a new water pump I would like to know the source of
information indicating that the correct water pump should be 4-1/4"
diameter,have a cast iron impeller with a backing plate (part #
412265-D24).The water pump I removed, which had been working fine, looks
just like the one Arch recieved from Cinnabar. I called my local Napa
dealer who had a 412265 water pump in stock. when we opened the box the
pump was brand new and looked like the one I just removed.I told him I
was sorry but I wanted the 4-1/4 diameter as advised by the GMC
gurus.They felt that using a water pump that increased the flow more
than the original design called for would actually increase the
temperature by pushing the water through the radiator too quickly.Since,
I have spoken to three different shop managers and they all agreed with
Napa. And one these managers, who builds engines, said that he had to
install a restricter on an engine that had a increased water flow
capacity in order to normalize the temperature.

Ray and Elias
1973 Painted Desert
Corning CA

 

[ron & gina]

Hi Ray and Elias

I'm not an old timer with the GMC/RVing Just over 6mos. But since I just
replaced mine (water pump/recored Radiator) thought I'd throw my 6mos.
experience out here. On my first trip with our Lady, On peaks of hills eng.
temp got to 250+ degs. But thanks to the GMC gods never had a boilover/or
had to stop/slow down to cool down. Checked NAPA's pump and it looked like
the one Arch had, So called Gateway and got their pump which was of the 4
1/4 close face design. The one to get. When I replaced water pump, the one I
pulled out was same type as NAPA's/Arch/Cinnabar. Now the removed pump was
not leaking(or I believe my heating problem ,it was a bad Rad.) but had
slight residue(not wet) out weep hole. All I can say is that, The 4-1/4 type
pump works great in this AZ. summer heat!!! stays on 1/4- mark, stock
sender, And when it does head upward fan comes on and back to 1/4. In CA.
Temp gauge goes below the 1/4 mark and no noise from fan. So I guess my
pump/Rad. is working great!!! Tranny?? But here's the kicker, The P.O. said
she never had heating problems, And she towed a toy. truck. So I guess both
of these pumps work great!!! If I had to do it over, I'd get the NAPA pump
the cheaper one which was the same as the one I took out which is my spare.
My 1/2 cent >

Ron&Gina
73 Pumpkin-Rose
Ft. Mohave, AZ. My wallet is starting to feel alot like Christmas....it
gets lighter.... everywhere we go..........

- ----- Original Message -----
From: "Ray Haywood"
To:
Sent: Tuesday, December 21, 1999 12:23 PM
Subject: GMC: 412265-D24 Water Pump

> Before I purchase a new water pump I would like to know the source of
> information indicating that the correct water pump should be 4-1/4"
> diameter,have a cast iron impeller with a backing plate (part #
> 412265-D24).The water pump I removed, which had been working fine, looks
> just like the one Arch recieved from Cinnabar. I called my local Napa
> dealer who had a 412265 water pump in stock. when we opened the box the
> pump was brand new and looked like the one I just removed.I told him I
> was sorry but I wanted the 4-1/4 diameter as advised by the GMC
> gurus.They felt that using a water pump that increased the flow more
> than the original design called for would actually increase the
> temperature by pushing the water through the radiator too quickly.Since,
> I have spoken to three different shop managers and they all agreed with
> Napa. And one these managers, who builds engines, said that he had to
> install a restricter on an engine that had a increased water flow
> capacity in order to normalize the temperature.
>
> Ray and Elias
> 1973 Painted Desert
> Corning CA
>