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Waterpump "HIGH OUTPUT"

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Bigred

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I know there are half a dozen threads on this, but I have not seen this problem. I cannot find a waterpump that is "HIGH OUTPUT" I have ordered 2 now from NAPA, and Advanced Auto Parts sells the same one, part #58-532(this is a reman). They are for a 1998, but they are identical to the stock pump I have for my 93 & 94. Does a Highoutput exist ? How do I get one ?

Thanks
 
Bigred said:
I know there are half a dozen threads on this, but I have not seen this problem. I cannot find a waterpump that is "HIGH OUTPUT" I have ordered 2 now from NAPA, and Advanced Auto Parts sells the same one, part #58-532(this is a reman). They are for a 1998, but they are identical to the stock pump I have for my 93 & 94. Does a Highoutput exist ? How do I get one ?

Thanks
Click to expand...

The 130 GPM pump (used on '97 and up with dual thermostat housing) is what most refer to as the high output. With that being said, any standard replacement pump for a '97 and up (tell them it's a '98 to be safe) should get you the high volume pump. One other way to verify is to measure impellers. The high volume pump has a 4.25" diameter trim, whereas the pre-'97 pump will have a 4.00" diameter trim.

According to what I've heard, the HO pump will work with the single stat, -but I'm not sure if a high-flow stat is required.

Rich.
 
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Like I said, the pumps for the 1998 they are selling are the same as the stock pump, 3-7/8 dia. impeller, I cannot find a pump with a bigger impeller.
 
Ratman said:
According to what I've heard, the HO pump will work with the single stat, -but I'm not sure if a high-flow stat is required.

Rich.
Click to expand...

Yes it works great with a single stat setup.

No, there isn't any "special stat" required for this setup. However, it is recommended that you use an AC Delco brand thermostat.
 
Bigred said:
Like I said, the pumps for the 1998 they are selling are the same as the stock pump, 3-7/8 dia. impeller, I cannot find a pump with a bigger impeller.
Click to expand...

Check with member MIKE K3500

I know he had an extra HO pump that he was looking to sell a few days ago.
 
Bigred said:
Like I said, the pumps for the 1998 they are selling are the same as the stock pump, 3-7/8 dia. impeller, I cannot find a pump with a bigger impeller.
Click to expand...

My apologies, I gave you the wrong trim dimensions. The low flow is 4.00", the high flow is 4.25". If they are selling you a 4" trim unit for a '98, then it isn't a HO pump.
 
HO pumps have "HO" cast in the face. I've bought a few Gates HO water pumps from Rockauto. ! came damaged from their crappy packaging. MIKEK3500 still had his for sale a couple days ago.
 
when you get one, don't forget to paint it before you put it on, Mine came in the raw and after I installed it I realized I should have painted it. The good thing is I dribble every time I put oil in and it has helped in rust management.
 
Thanks everyone, I found one at O'Rielly's, same part # as napa(58-532)($54) ,but is the HO. Be carefull what they try to sell you out there.
 
Thanks, Ace, yea I have been keeping up with the posts on both sites lately or I would of not known the one they were selling me was not a HO. I took my plate with me and double checked, everything looks good.
 
Thought that as long as they sell you a 1997+ water pump, it has to be the HO pump in any case. In my mind, starting 1997 (even late 1996), GM has set the 2nd design twin T-stats which must go with the 130 GPH HO pump.
ACDelco cast HO on their #252717 water pump. e.g. Airtex do not for their AW5074, but AFAIK, they are both HO, aren't they ?
 
matuva said:
Thought that as long as they sell you a 1997+ water pump, it has to be the HO pump in any case. In my mind, starting 1997 (even late 1996), GM has set the 2nd design twin T-stats which must go with the 130 GPH HO pump.
ACDelco cast HO on their #252717 water pump. e.g. Airtex do not for their AW5074, but AFAIK, they are both HO, aren't they ?
Click to expand...

The only way to know for sure is measure the impeller size, should be 4-1/4 dia.
 
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