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Discussion Starter · #1 · (Edited)
Hello... I have a 67 Impala, 350 small block engine... My problem is that I've had to replace 3 water pumps within less than 100 miles of using each one because they all leaked from the weep hole. I replaced 1 myself, and had the other 2 replaced at a shop in case I did something wrong. I don't remember the name brand of the first pump, but the 2nd two were both Gates (bought from the same vendor). I've known the owner of this shop for 20+ years so I trust he isn't ripping me off, however I'm a bit frustrated that a professional mechanic can't think outside the box and find out why each pump keeps having the same problem. My car is not overheating; I actually drove cross country twice with a leaky weep hole (just kept checking coolant every few days, topped off if I needed to). Worst case is I'd probably lose 1 cup of coolant every 3 months. I'm at the point where I'm ready to throw in the towel and keep an eye on the coolant, top off if/when needed, and keep driving. Keep a spare water pump/coolant in the case in case i break down and replace on the spot if needed. I keep an eye on the temp gauge all the time and my car temp is fine. This is my everyday driver and I've never really had any major problems with it, the leak is mainly bothering me because I like to have a leak free car. Any ideas what could cause the weep hole to always leak. I've read it could be a fan clutch, and belts not properly tightened (I've checked both and they are both fine). Any help would be appreciated!

Thanks!
 

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Wp

I also got mine from Napa, have a 1966 Impala. They were very helpful an d even helped me find a correct date code for my car. First time I errored in that I tightened the water feed nipple too tight and created a small crack in the housing it screws into. Second time all perfect.
Agree with just getting poorly rebuilt or low quality new ones.
Paul
 

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I also recommend specifying a Corvette water pump instead of the passenger car. The Corvette water pump uses a sixteenth of an inch bigger diameter shaft and the bearings are much bigger to hold it in place at high RPM.

Unless you are using the stock cam and do not frequently drive above forty five miles an hour (the average highway speed when your car was new and the speed that was used to design the car's requirements) you are probably reving the water pump faster than it was designed to operate.

I use a Stewart Phase III aluminum water pump which uses the Corvette size shaft and big bearings with a CNC machined enclosed scroll to move the water instead of Mr. Fullton's steam boat's paddle wheel that Chevy does inside your stock water pump. The Stewart Phase III water pump moves 40% more water at half the horsepower.

A cheaper compromise is to buy an Edelbrock aluminum water pump that uses a fully enclosed paddle wheel (squirrel cage) with he bigger shaft and bearings. All high performance water pumps use an improved seal to keep the water from leaking past the seal to exit via the weep hole. You can grind Edelbrock's name off the pump and paint it orange and only a car show judge would know the difference.

I also recommend your checking not only the belt tension (being too tight is the leading cause of failure), but belt misalignment will also cause the seal to fail.


Big Dave
 

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There are 3 types of water pumps. #1 Rebuilt, where they replace what wore out and resell it. Also the cheapest. #2 Re manufactured, where they replace all internal parts. #3 New, all new housing and internals. I try to always buy new.
After installing, careful of over tightening belt as the front bearing and seal cant handle to much torque.
 

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Discussion Starter · #6 ·
Thanks everyone... all of your responses were exactly the types of answers I've been looking for.

I've been doing some more research and came across a few threads that stated some water pump manufacturers say 1) It's normal for a small bit of coolant to leak out of the weep hole, and 2) The pump can leak for some time while the seals settle.

What are everyone's thoughts?
 

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Discussion Starter · #7 ·
I also got mine from Napa, have a 1966 Impala. They were very helpful an d even helped me find a correct date code for my car. First time I errored in that I tightened the water feed nipple too tight and created a small crack in the housing it screws into. Second time all perfect.
Agree with just getting poorly rebuilt or low quality new ones.
Paul
Paul, Thanks, I'm gonna try purchasing the pump somewhere else rather than warranty exchanging it through the same place. what type of water pump did you end up using on your 66? How long has it lasted? And what type of engine do you have?

:)
 

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Discussion Starter · #8 ·
Can anyone tell me the rule of thumb they use when tightening the belts? I've been told that if you can turn the belt 1/4th of a turn then it's tight enough. I've had 2 different mechanics take a look at the belts for a second opinion and they said they were fine. Wondering what method everyone else uses???

What I've noticed is that the belts go on tight when initially tensioning them, but as you drive they loosen up just a little and stay that way.
 

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Discussion Starter · #9 ·
I also recommend specifying a Corvette water pump instead of the passenger car. The Corvette water pump uses a sixteenth of an inch bigger diameter shaft and the bearings are much bigger to hold it in place at high RPM.

Unless you are using the stock cam and do not frequently drive above forty five miles an hour (the average highway speed when your car was new and the speed that was used to design the car's requirements) you are probably reving the water pump faster than it was designed to operate.

I use a Stewart Phase III aluminum water pump which uses the Corvette size shaft and big bearings with a CNC machined enclosed scroll to move the water instead of Mr. Fullton's steam boat's paddle wheel that Chevy does inside your stock water pump. The Stewart Phase III water pump moves 40% more water at half the horsepower.

A cheaper compromise is to buy an Edelbrock aluminum water pump that uses a fully enclosed paddle wheel (squirrel cage) with he bigger shaft and bearings. All high performance water pumps use an improved seal to keep the water from leaking past the seal to exit via the weep hole. You can grind Edelbrock's name off the pump and paint it orange and only a car show judge would know the difference.

I also recommend your checking not only the belt tension (being too tight is the leading cause of failure), but belt misalignment will also cause the seal to fail.


Big Dave
Thanks, Dave. Any chance you could help me pick out a few good pumps that you recommend for my vehicle? Also, how will I know if these pumps will fit in my car? I have a 350 small block engine, I could try sending a picture if that helps. I checked out a few pumps on the Stewart website, and some Edelbrock ones on e-bay - there's so many options and I'm not sure which one will work for my car. I saw some Chevy Bolt Kits on the Stewart website (is that all I need to fit the pump?). I don't mind spending a few extra bucks to get a pump that works - but obviously if there's a cheaper pump that will work I'd pick that one first :).
 

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Caveat Emptor! NAPA has two price plan's. If you walk in the door and the counter (person) man doesn't know you they will sell you the same Indian and Chinese junk that every other corner auto parts store offers to stay in business. NAPA also offers, if you specifically ask for it, a "As good as, if not better than, factory warranty replacement part" under a premium parts label (Weatherhead for fittings, Raybestos for brakes, Moog for suspension parts, Bilstein or Monroe for shocks, Walker for Mufflers, Belkin for electrical wiring and switches, etc.). So be sure to ask for the "high priced spread", unless you want more margarine.

Chevrolet made their own water pump rather than buy them from any of their OEM suppliers that I mentioned above, for those parts. The pump casting is rarely the problem. The quality of the seal, and the bearing (GM used Timken bearings as their OEM source) is what you are after. Today Timken is sourcing some of their bearings from China, so that they can have a product to sell to the bottom feeders interested only in price, so you have to ask for the American made product specifically.

If you had a five ton arbor press or even a twenty ton shop press you could buy a quality rebuild kit from NAPA and rebuild your pump in your own garage using your original date coded water pump casting (if that was important to you). I have rebuilt a lot of water pumps because the kit was cheaper than the part offered to me at Jobber, and it was so easy to do taking less time than it took for the part to be delivered to my shop.

When ordering, like I said above you get a better pump that should bolt right up without issue if you ordered a Corvette water pump.

I have never had a problem though I did have to enlarge the water pump pulley hole with a drill bit once on a 1955 car with an early sixties 327. I believe this was because the Corvette hadn't as yet received it's larger diameter pilot shaft so none of Chevy's pulleys in 1955 where machined for that sized shaft.

Even with a stock pump; remind the counter attendant of your year of car so that you do not receive a late model counter rotating water pump found on serpentine belt cars. When you open the box inspect it for rust and a tight fit on the hub (it should be hard to turn not loose). The hub mounting holes should have 1-3/4" inch diameter bolt pattern with fine threads that are clean and crisp. The pump itself shouldn't have dents in the attaching bolts where a washer sank into the metal from being over tightened.

Chevrolet still sells new a pre 1969 (short) water pump with both the 1-3/4" inch diameter bolt pattern used by your car (early short water pumps) and the larger 2-1/8th inch diameter bolt patter used on the long pump. This short cast aluminum water pump has the larger Corvette shaft and water pump impeller inside designed to cool a high performance car. It is currently sold under Chevy part number 14011012.

An Edelbrock short water pump is still going to be the best compromise between a racing pump and a stock one. I have used them for years without an issue and have bolted a lot of them on customer's cars that I have built in my shop. The only draw back is waiting for it to arrive on the brown truck, especially this time of year (I wouldn't want to be a UPS driver even though they are making a killing in OT, their back must be killing them). No special bolts are need unless you what a chromed set, or better yet a Stainless Steel set of ARP bolts also delivered mail order.

Good luck!

Big Dave


P.S this article should be able to answer any questions you have on water pump style and pulleys or brackets for a SBC.

http://www.chevyhiperformance.com/techarticles/49718_small_block_pumps_pulleys_brackets/

Note the dialog under the picture with the two pumps and the ruler across the top! This is most likely the cause of your water pump failure as if belts are out of line the forces pulling at an angle will wear one side of the seal causing a leak.

Big Dave again
 

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Water Pump

It was an OEM rebuilt warer pump from Napa. Purchased it approx. 5 years ago, still no issues. However, don't drive the car much, unfortunately, spends more garage time than road time.

Paul
 

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Discussion Starter · #16 ·
Caveat Emptor! NAPA has two price plan's. If you walk in the door and the counter (person) man doesn't know you they will sell you the same Indian and Chinese junk that every other corner auto parts store offers to stay in business. NAPA also offers, if you specifically ask for it, a "As good as, if not better than, factory warranty replacement part" under a premium parts label (Weatherhead for fittings, Raybestos for brakes, Moog for suspension parts, Bilstein or Monroe for shocks, Walker for Mufflers, Belkin for electrical wiring and switches, etc.). So be sure to ask for the "high priced spread", unless you want more margarine.

Chevrolet made their own water pump rather than buy them from any of their OEM suppliers that I mentioned above, for those parts. The pump casting is rarely the problem. The quality of the seal, and the bearing (GM used Timken bearings as their OEM source) is what you are after. Today Timken is sourcing some of their bearings from China, so that they can have a product to sell to the bottom feeders interested only in price, so you have to ask for the American made product specifically.

If you had a five ton arbor press or even a twenty ton shop press you could buy a quality rebuild kit from NAPA and rebuild your pump in your own garage using your original date coded water pump casting (if that was important to you). I have rebuilt a lot of water pumps because the kit was cheaper than the part offered to me at Jobber, and it was so easy to do taking less time than it took for the part to be delivered to my shop.

When ordering, like I said above you get a better pump that should bolt right up without issue if you ordered a Corvette water pump.

I have never had a problem though I did have to enlarge the water pump pulley hole with a drill bit once on a 1955 car with an early sixties 327. I believe this was because the Corvette hadn't as yet received it's larger diameter pilot shaft so none of Chevy's pulleys in 1955 where machined for that sized shaft.

Even with a stock pump; remind the counter attendant of your year of car so that you do not receive a late model counter rotating water pump found on serpentine belt cars. When you open the box inspect it for rust and a tight fit on the hub (it should be hard to turn not loose). The hub mounting holes should have 1-3/4" inch diameter bolt pattern with fine threads that are clean and crisp. The pump itself shouldn't have dents in the attaching bolts where a washer sank into the metal from being over tightened.

Chevrolet still sells new a pre 1969 (short) water pump with both the 1-3/4" inch diameter bolt pattern used by your car (early short water pumps) and the larger 2-1/8th inch diameter bolt patter used on the long pump. This short cast aluminum water pump has the larger Corvette shaft and water pump impeller inside designed to cool a high performance car. It is currently sold under Chevy part number 14011012.

An Edelbrock short water pump is still going to be the best compromise between a racing pump and a stock one. I have used them for years without an issue and have bolted a lot of them on customer's cars that I have built in my shop. The only draw back is waiting for it to arrive on the brown truck, especially this time of year (I wouldn't want to be a UPS driver even though they are making a killing in OT, their back must be killing them). No special bolts are need unless you what a chromed set, or better yet a Stainless Steel set of ARP bolts also delivered mail order.

Good luck!

Big Dave


P.S this article should be able to answer any questions you have on water pump style and pulleys or brackets for a SBC.

http://www.chevyhiperformance.com/techarticles/49718_small_block_pumps_pulleys_brackets/

Note the dialog under the picture with the two pumps and the ruler across the top! This is most likely the cause of your water pump failure as if belts are out of line the forces pulling at an angle will wear one side of the seal causing a leak.

Big Dave again
Dave, This is all great info/link... exactly what I wanted! If you got a moment could you please send over some links to an Edelbrock pump that would work for my car? I looked at a few but none say they are specifically for a Corvette. I saw some for Camaros. I want to make sure I get one with the bigger shaft and stronger bearings, along with the improved seal you mentioned. Any help/guidance would be appreciated - please let me know if you need more info about my car.

Thanks! :)
 

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Discussion Starter · #17 ·
I'm curious... if I sealed the weep hole, would my waterpump just go out all of a sudden? I pay close attention to my car gauges when I drive and check fluids every 3 or 4 days so I'd know if I was losing coolant or overheating.
 

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Discussion Starter · #18 ·
What are everyone's thoughts on an electric water pump? I've gotten a second opinion on my serpentine belts and they are aligned properly - the tension is fine as well. If it ends up that I'm just getting bad water pumps then a better pump may fix the issue, however to avoid any belt issues altogether is there any benefit to using an electric water pump? This car is my every day driver - I drive highways as well as streets, and do take long 500+ mile road trips on the regular. I don't race my car at all but do drive hard for 3 to 5 straight hours on highways sometimes (depends on when I'm low on gas haha...).
 

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What are everyone's thoughts on an electric water pump? I've gotten a second opinion on my serpentine belts and they are aligned properly - the tension is fine as well. If it ends up that I'm just getting bad water pumps then a better pump may fix the issue, however to avoid any belt issues altogether is there any benefit to using an electric water pump? This car is my every day driver - I drive highways as well as streets, and do take long 500+ mile road trips on the regular. I don't race my car at all but do drive hard for 3 to 5 straight hours on highways sometimes (depends on when I'm low on gas haha...).
Since you have a serpentine belt system you do not normally tighten the belts other than the initial installation. There is a spring loaded belt tensioner that is adjusted to a specified mark (preload on the spring). If you are using a Chevrolet system from the junkyard or if purchased new as a kit:

http://www.jegs.com/i/Chevrolet+Performance/809/12497697/10002/-1

The belt tensioner will take up any slack in the belt as it stretches once installed.

If you are using a March, Zoops or other brand of serpentine belt that doesn't use a belt tensioner then you use a special tool that is included in the kit.

http://www.jegs.com/p/March-Perform...olet-Serpentine-Pulley-System/957091/10002/-1

As the belt stretches you have to periodically manually retension the belt using the tensioner to measure how much tension is in the belt (basically a spring fish scale).

As to specific models from Edelbrock they sell two water pump castings (short and long) for a first generation small block Chevy and change the impeller to compensate for normal and reverse rotation which changes direction when using a seperntine belt compared to a V-belt.

As I understand it you have an early motor (built before 1969) which would normally be using a short style normal rotation water pump. But because you have a serpentine belt system you need to buy a long reverse rotation water pump assuming you are using a stock Chevrolet belt drive as found in a junk yard on a stock 305 motor. Now if you are using a March or Zoops belt drive that uses brackets with turn buckle tensioners and a short water pump it will depend upon how the belt is routed to determine if you use a normal or reverse rotation water pump.

If you do not get the rotation going in the correct direction then yes you can burn up the seal in a matter of weeks as the coolant circulating through the pump also lubricates the bearing and the seal. If you turn it in the wrong direction the impeller just boils the water in side the pump and you motor will run hot.

We need a picture of your car's motor showing the water pump and the belt routing to advise further.

Big Dave
 

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Discussion Starter · #20 ·
Since you have a serpentine belt system you do not normally tighten the belts other than the initial installation. There is a spring loaded belt tensioner that is adjusted to a specified mark (preload on the spring). If you are using a Chevrolet system from the junkyard or if purchased new as a kit:

http://www.jegs.com/i/Chevrolet+Performance/809/12497697/10002/-1

The belt tensioner will take up any slack in the belt as it stretches once installed.

If you are using a March, Zoops or other brand of serpentine belt that doesn't use a belt tensioner then you use a special tool that is included in the kit.

http://www.jegs.com/p/March-Perform...olet-Serpentine-Pulley-System/957091/10002/-1

As the belt stretches you have to periodically manually retension the belt using the tensioner to measure how much tension is in the belt (basically a spring fish scale).

As to specific models from Edelbrock they sell two water pump castings (short and long) for a first generation small block Chevy and change the impeller to compensate for normal and reverse rotation which changes direction when using a seperntine belt compared to a V-belt.

As I understand it you have an early motor (built before 1969) which would normally be using a short style normal rotation water pump. But because you have a serpentine belt system you need to buy a long reverse rotation water pump assuming you are using a stock Chevrolet belt drive as found in a junk yard on a stock 305 motor. Now if you are using a March or Zoops belt drive that uses brackets with turn buckle tensioners and a short water pump it will depend upon how the belt is routed to determine if you use a normal or reverse rotation water pump.

If you do not get the rotation going in the correct direction then yes you can burn up the seal in a matter of weeks as the coolant circulating through the pump also lubricates the bearing and the seal. If you turn it in the wrong direction the impeller just boils the water in side the pump and you motor will run hot.

We need a picture of your car's motor showing the water pump and the belt routing to advise further.

Big Dave
Dave, sorry about the confusion... I was looking over at the links you sent and did some research as I was a bit confused. I thought serpentine belts were when you have multiple belts running multiple accessories (ie. a/c compressor, water pump, power steering pump, and alternator running on different belts), which is what I have. After doing some research I found that the correct term for this particular setup is "v-belt". Just to clear it up, I have 3 separate belts that run the following accessories: a/c compressor, power steering pump, water pump, and alternator. That said, maybe you could better guide me on what I need. I have taken a few pictures of my engine this morning after reading your response but didn't get a chance to copy them over to my computer as I was taking care of my baby son all day. I'll post the pics as soon as possible. Again, my bad for the confusion - just learning as I go.
 
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