Can someone tell me the difference between a a/c and non-a/c nailhead water pump (364)....Does the a/c version have more vanes, hence more coolant flow?...would it work on a non-a/c car. TIA, J.T.
I had some trouble on my 61 with the water pump. The waterpump on the 401 is not interchangeable between the AC and non-AC cars. If you try to put a AC-pump on a non-AC car you get a leak at the lower hose connection. I assume it would be the same on the 364. The photo shows the water pump for a non-AC 401 pump. I have a photo on the AC pump too, I can post that one too if you want.
Thanks. That is strange, as they only list one gasket for both pumps, so the mounting points must be the same. I assumed they are different due to a different size snout to accomodate an extra pulley ring for the a/c compressor? o No: I would appreciate it if you could post the other picture. Thanks Hans.
Guys-I'm more tuned in with the later 401/425, and with them it is a vane issue-3 standard and 5 with A/C. I recall that earlier (364?) engines did have a different w/p profile and it was in the area of the right side in the pic. Do a search for past postings as there was past discussion as to vane height and length (rebuilder production variances) that were found by some to be more important than simply the vane count-good luck
AC pump Here is the pic on the AC pump. As you can see there is a difference around the lower hose area so they use different gaskets. If this is the case with the 364 I dont know. There might be some difference in lenght too but on my pump there is a extension that puts the fan close to the radiator. Hope this helps a little.
The only way to that as far as I know is to change the front cover of the engine. They can be found on ebay from time to time. I am not sure you can interchange these between earlier and later 401s.
Aside from the waterpump gasket surface/area, I believe that the front covers will interchage. They bolt up to the engine and the oil pan the same. I would not put my life on this but I would bet the first round of beer on it!!! :beer :beer :beer
I had seen this in a post a while back just some FYI. I read an article in streetrodder magazine a while back that stated the 5 impeller pump moved the water through the engine and cooling system too fast and actually made the nailhead run warmer than with the smaller 3 blade impeller. makes sense when you look at the pulley diameter of an a/c pulley vs the diameter of a non a/c pulley. that water pump is seriously overdriven on A/C cars. i think i would start with a non a/c water pump and the a/c pulley and see how the car runs. Bob __________________ BPG member 1767 you can attract more flies with honey than vinegar.....but you can can attract the most with a dead possum
water pumps I wonder. Why did Buick do all that research, designing, testing, and then produce a water pump that doesnt work as good as the one they already had to put on their a/c cars???????? Given the fact that the thermostat slows down and controlls the flow of coolant, not the water pump. The water pump is designed to move more than needed to cool the engine under all conditions, then the thermostat controlls the amount of flow.
I've been wondering about this myself. I have a '62 401 that wants to run warm at idle. Runs cool while cruising but gets hot in traffic and parades on hot days ideling. Not equipt with A/C but was wondering about putting an A/C pump on or maybe just the smaller A/C pulley. Haven't had any luck trying to locate the pulley except for some nutcase who wanted $350 for it! Anyone know where I could find this pulley?
