autozone water pump with or w/o A/C??

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eviper21

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Im getting a waterpump for my 318 from autozone. Theyre $37 for a new pump with A/C and $52 without A/C

my car doesnt have A.C but the price is so much cheaper. Im wondering if ill be ok with the waterpump for A/C cars or is there some special port or waterway with that one?

lemme know, thanks!
 
I believe the one with A/C would also have one more blade. Check both out, which ever has more blades get that one. And all you need to do is plug the holes not using, since you have no A/C
 
Pretty sure ac has 6 blades and non ac has 8 for the early style pump... Buy a new one if you can. My reman didn't last a year before it leaked.
 
The only difference between the two pumps should be that the A/C pump "should" have more impeller blades (eight), opposed to the non-A/C (six).
Otherwise all else should be the same.
 
..i think the impeller count is determined by the water pump pulley width.
..the small pulley will spin more so 6 blades would be correct.
..if you have the large water pump pulley it will spin slower so the 8 blade pump would be required...some say spinning the 8 blade faster will cause cavitation.
 
ir3333 said:
..i think the impeller count is determined by the water pump pulley width.
Click to expand...
Why I love this site. Always some new and interesting info. The "AC" water pump is only called that because AC cars had a different diameter pulley. Makes perfect sense. Whether AC or non-AC you would always want the max possible water flow to increase cooling. There is a reason the Mopar designers did certain things. It is our task to determine why. Most of them are in the grave or a nursing home today, so no way to get the real word unless someone finds an old engineering document.
 
theyre both new pumps, and it seems that the A/C would be better anyways based on your guys' input? lol

i should just get the A/C pulley also as to not spin the pump to fast?
 
8 blade water pump This pump came on my 2003 Magnum Crate motor.
I used the pulley from a non air 340, and it measures 6 7/8" Diameter.

Do you guys use any added water pump lubricant, I heard that it's not in the anti freeze any more, but I don't know for sure.
 
BillGrissom said:
Why I love this site. Always some new and interesting info. The "AC" water pump is only called that because AC cars had a different diameter pulley. Makes perfect sense. Whether AC or non-AC you would always want the max possible water flow to increase cooling. There is a reason the Mopar designers did certain things. It is our task to determine why. Most of them are in the grave or a nursing home today, so no way to get the real word unless someone finds an old engineering document.
Click to expand...

Bill, I would assume that an AC car sitting at idle with the AC on is going to require more cooling than a non AC unit. Seems to make sense. Dan
 
eviper21 said:
theyre both new pumps, and it seems that the A/C would be better anyways based on your guys' input? lol

i should just get the A/C pulley also as to not spin the pump to fast?
Click to expand...


i wonder if you can pass the water through the radiator too fast at times. i guess if you have a good thermostat in the motor that the stat should restrict it enough to stay in the radiator long enough to remove the heat.


problem with going with an a/c pulley is then nothing lines up properly. stick with what you have.
 
just for reference. here are the differences between the 70-up a/c and non a/c water pump pulleys.


the chrome one is non a/c....

DSCN5193.jpg


DSCN5194.jpg





non a/c pulley measurements..
pulley2.png
 
exact same pump, with a different impeller count. only the pulley used is different. the shaft and the pulley mount are the same exact thing.
 
abodyjoe,
This is starting to explain things. For years, several FABO people have claimed/wondered if moving the water too fast thru the engine could actually reduce the cooling, and some claimed practical experience to back that up. It makes no sense from an engineering standpoint (my MS thesis was in Heat Transfer), but your info starts to explain what they observed. They probably found that a small pulley, 8-bladed pump combination caused cooling problems, and either slowed the pump (larger pulley) or crippled the pump (6 blade impellor or restrictor washer) and found that fixed the problem. Perhaps the problem was not due to too much water flow, but rather too little flow from a cavitating pump. My main question is when it might cavitate since the engine runs through a wide range of rpm's and most people notice cooling problems near idle (maybe after having run at high rpm?).

I recall putting the 8-blade aluminum "AC" pump in my 65 Dart, and my after-market aluminum pully has similar diameter as my factory pulley, except shorter depth. My factory pulley looks like your non-AC pulley, but w/ straight sides and about the same depth. I haven't driven enough to know if an over-heating problem. If so, I will try a 6-blade water pump.

As a side-note, I wonder why the "AC" pulley in your photo has a single groove. I thought 70-72(+?) AC cars used 2 belts for the compressor, in the grooves closest to the engine, shared w/ the water pump.
 
As a side-note, I wonder why the "AC" pulley in your photo has a single groove. I thought 70-72(+?) AC cars used 2 belts for the compressor, in the grooves closest to the engine, shared w/ the water pump.
Click to expand...

70-up the daul belts went crank, a/c compressor ( actually passes behind the smaller water pump pulley), alt.

then a single belt went crank, water pump, ps pump..

pulley068.jpg
 
either way i would find a different supplier.. even with the warranty i lost out on my last Dura(wont)last water pump was replaing it every 6 months after the second pump i bought a different one and never had to replace it again.
 
You CAN have too much coolant flow (like when you leave the thermostat out) and the pump CAN cavitate if the wrong pump is used. Just use the correct pump and you will eliminate that variable from any cooling system problems.
 
I'm going thru this problem. Purchased a AC water pump and had cooling issues. This is how it was explained to me.

Also had a under drive march pulley, once that was changed it helped, but still heated up more than I wanted at idle.

AC cars had 6 blade vain & a smaller water pump pulley

Non AC had 8 blade larger pulley than AC

The thought from Chrysler was they would both flow the same amount of water and the AC car would flow more air thru the radiator.

I purchased a FLOWCOOLER water pump for my 340, hope this cures the cooling issues at idle. It has an anti cavitation plate, is to flow up to 40 percent more at idle and the same at speed

Hope to get the car back in the next few weeks and see if it really works.
 
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