I'm doing a serpentine-belt conversion on the 350 I'm planning on installing over Christmas Break. I've been researching different pump options, and being the tight-fisted scrooge I am, I want the best I can get for cheap as I can get. So far as I can tell, GM has made a "Heavy Duty" water pump for serpentine applications on the 1990 Caprice with a 5.7L engine. Here is the Description from the Print NAPA catalog... [Water Pump] Perf. Pump; Reverse Rotation not Interchangeable with Standard Rotation; OE #12522031/10077059; OE Cast. #10108451/14102026 Apparently it has a heavier duty bearing and hub. The rebuilt pump sells for $29.99 with a $4.40 core charge. Methinks I'm going to go this route with my junk yard brackets and alternator, with aftermarket pulleys.... My Question Is has anyone heard about this? Will it work on this motor I'm doing? Is this something other ThirdGen owners with Serpentine set-ups should know about?

when i bought a water pump i bought the HD version....it came up under camaro.....but they're ALL the same size shape, etc.....it's ALL serp. SBC reverse-rotation....so go for it.

That's kinda what I thought. The price for a non-heavy duty pump is about half of what the heavy duty one sells for. Thanks for the tip.

exactly.

just curious what kind of warranty is on the rebuilt water pump?


and to answer your questions.

yes just about anyone who has bought a water pump knows about this. unless they have someone do the work for them.

yes it will work on your motor, xpndbl3 answered that pretty well

and im pretty sure most thirdgen people know about this, most of us actualy go a few steps up from that and get a Stewart pump.

Napa's website doesn't list warranty info for anything, however, I'd lean toward lifetime, because I've bought a reman alternator from Napa that holds a lifetime warranty. At the very least, I think Napa does 1 year for most anything not lifetime.

lifetime would be nice. but i know at most parts stores rebuilt waterpumps carry 1 yr warranties. so if it did have a lifetime warranty that would be a pretty good deal. usualy alot of lifetime warranty alternators which are rebuilt use new internals and a reused case..

for example, at autozone, a Valuecraft rebuilt starter carries a 1 yr warranty, and they pretty much get away with replacing as few parts as possible

a Duralast Alternator used mostly all new Internal compenents, while the case is reused.

A Duralast Gold Alternator uses 100% new pieces, internal and external.

now you know the rest of the story

I am using a Flow-Kooler water pump and it doesn't seem to help me. The BeCool radiator (2 one inch aluminum cores) only slowed down the heating process. I am using a Mr. Gasket hi-flow thermostat as well. Not to mention the transmission cooler.... Around town driving in the summer with the A/C on in this thing will net you 270* if you are not careful. Of course it does see 100* plus on a consistent basis here is Bakersfield. A buddy of mine recently told me he doesn't use overdrive around town due to the heat buildup it causes. Seems I have heard that before, so I will try that this summer to see if it helps.

Anybody else have any good ideas????? BTW, I converted over to serpetine about 3 years ago. The only problem I had was finding the proper power steering pump. I have a standard 1800# PS unit instead of the 1200# unit... Can be real touchy in the curves at high speed.

I've read a book by David Vizard called small block chevy high performance and it seems that you get improved effiency when you plug the bypass in the block (the odd hole one one of the pump outlets) and drill 4 holes in your thermostat. They also mentioned running a HIGHER pressure radiator cap.

I used to have severe trouble with cooling until I realized the heater core had a pinhole leak in it. I still can get warm sitting and idling...but norma driving above 35MPH is a rock-steady 185* I have an aluminum stock replacement radiator with a 180* thermostat. I'm looking into an adjustable fan switch to solve that problem when I drop the motor in.

I had a buddy that tried the hole thing on his Vette and he said it didn't help. I'm running a 180* thermostat in the summer (Normally the winter too, but I just had to smog it so I changed to the 195*) I have run a 22# cap but I had a weak heater core... Notice I said had... I have an all aluminum radiator so running the higher pressure cap is no problem in the summer.

I have a 10" and a 16" fan behind the radiator. The 10" runs all the time and the " is wired into a thermostatic fan switch that comes on at 205 and shuts off at 190*. I have a 10" and a 14" in front of the radiator that currently is wired into the factory harness and come on at 238*. The car runs 220* down the highway in the summer with the A/C on. I also used Water Wetter this summer but I had problems thatkept me from driving the car this summer so I can't say that it did or didn't do me any good. I have another bottle to put in this summer. Actually, using a cap full of Formula 409 should do about the same thing. It breaks the tension of the water surface and allows it to penetrate better. The fire departmentputs about a cup full in their water tanks so water will penetrate into mattresses better.

I normally have both 10" fans on all the time and the two larger fans wired into the fan switch. I have problem with the A/C freezing up during around town driving so I wired it as mentioned above to see if maybe too much cooling was taking place in the condenser. Froze up the pump anyway.... I think maybe the A/C was overcharged. This time I'm doing the A/C work instead of farming it out. I need to buy a good set of gauges since all I have is a fill line and a separate line for checking low side pressure (or fuel pressure.....).

the solution to all overheating problems is finding the true problem and fixing it.


everything else is a bandaid.






as far as HD stock replacement pumps.....they're the bare min... if you want improved cooling, alot of the aftermarket pumps seem to work better... or if you're cheap, you can put a backing plate on your stock impeller...