Water Pump wobbles
Thread Starter
Le Mans Master
Joined: Jan 2001
Posts: 6,741
Likes: 1,383
Water Pump wobbles
I noticed an oddball noise when idling my 68 today. It seems that the water pump is wobbling....pretty funny considering it isn't leaking. I guess it's time to replace it; any pointers? Suggestions?
Melting Slicks
Joined: Aug 2001
Posts: 3,050
Likes: 124
From: Wichita KS
Re: Water Pump wobbles (carriljc)
carriljc
You might check the CF archives. Do a search under "water pump", LOTS of opinions. General recommendation is to NOT use a rebuilt water pump. New GM (and others) water pumps are not that expensive.
Most likely your water pump uses "short style" mounting legs - used on pre-1982 Corvettes. Most people favor the aluminum water pumps because of their lighter weight.
The GM Performance Parts PN for an aluminum water pump with short legs and 3/4" diameter shaft is 14011012. They also list a cast iron water pump with short mounting legs for 71-82 Corvettes GMPP 12458924. I don't know what changed in 1971.
You might also check the Corvette Forum vendors.
I have included a couple of links that should help. The "Lars" paper is probably what you need.
http://www.corvettefaq.com/engine.asp
How to Replace Timing Chain and Water Pump - by Lars Grimsrud
You might check the CF archives. Do a search under "water pump", LOTS of opinions. General recommendation is to NOT use a rebuilt water pump. New GM (and others) water pumps are not that expensive.
Most likely your water pump uses "short style" mounting legs - used on pre-1982 Corvettes. Most people favor the aluminum water pumps because of their lighter weight.
The GM Performance Parts PN for an aluminum water pump with short legs and 3/4" diameter shaft is 14011012. They also list a cast iron water pump with short mounting legs for 71-82 Corvettes GMPP 12458924. I don't know what changed in 1971.
You might also check the Corvette Forum vendors.
I have included a couple of links that should help. The "Lars" paper is probably what you need.
http://www.corvettefaq.com/engine.asp
How to Replace Timing Chain and Water Pump - by Lars Grimsrud
Le Mans Master
Joined: Sep 2001
Posts: 7,739
Likes: 630
From: Unreconstructed, South Carolina
Re: Water Pump wobbles (carriljc)
Yep ... 71 up sbc C3 had 3/4" pilot. In general, many performance pumps have a 3/4" shaft but are available with either 5/8" or 3/4" pilot (the stub the pulley & fan-clutch locate on). I won't swear to it (y'all correct me if need be) ... but I believe the primary difference in pre 71-wp is that the 70-back pump has the 5/8" pilot. Chevy also uses two different bolt patterns (on pulley hub) but I don't know how that coincides with years/models. Regardless the 68 is a short pump. Don't bother with a rebuilt wp ... nowadays a new OE-replacement wp is no more than $25 above what a rebuilt one costs.
A wobble can fool ya ... sometimes the wobble in the fan-clutch can look like wp shaft wobble.
But don't let lack of leak fool ya. I just replaced wp on a 106,000 mile fwd Olds V6 ... wp locked up ... DID NOT LEAK ... but bearing was so bad the shaft & impeller were so badly cocked in housing the impeller gouged the housing ... but it never leaked. Whoever designed the seal on that wp deserves an award for excellence.
A wobble can fool ya ... sometimes the wobble in the fan-clutch can look like wp shaft wobble.
But don't let lack of leak fool ya. I just replaced wp on a 106,000 mile fwd Olds V6 ... wp locked up ... DID NOT LEAK ... but bearing was so bad the shaft & impeller were so badly cocked in housing the impeller gouged the housing ... but it never leaked. Whoever designed the seal on that wp deserves an award for excellence.
Pro
Joined: Aug 2000
Posts: 713
Likes: 1
From: plymouth mass
Re: Water Pump wobbles (jackson)
Hi Jackson:
If the water pump is wobbleing, replace it, don't wait for it to let you down. In my opinion, buy a new one, but over the years I have had mixed results with both rebuilt and new. If the pump is the original don't turn it in for a core. The original pump is part of the number matching deal for all you NCRS types. Save the original pump and have it rebult at a later date.
Chuck D
If the water pump is wobbleing, replace it, don't wait for it to let you down. In my opinion, buy a new one, but over the years I have had mixed results with both rebuilt and new. If the pump is the original don't turn it in for a core. The original pump is part of the number matching deal for all you NCRS types. Save the original pump and have it rebult at a later date.
Chuck D
Thread Starter
Le Mans Master
Joined: Jan 2001
Posts: 6,741
Likes: 1,383
Flowkooler water pump from Summit
I'm looking at the Flowkooler in the Summit catalog. Says it flows up to 30% more than stock. Anyone have any experience with this pump?
I'll go measure my pilot and make sure it is 5/8".
I'll go measure my pilot and make sure it is 5/8".
Pro
Joined: Sep 2002
Posts: 620
Likes: 2
From: San Antonio TX
Re: Water Pump wobbles (carriljc)
You didn't say if the wobble was in the shaft or the assembly itself. Regardless, don't mess around, fix it fast. It's amazing the damage a bad pump can do, beyond the obvious. Just prior to taking a long 12 hour trip, I checked the engine and noticed that one of the water pump bolts was not tight. turns out that it was somehow stripped. Not having much of a choice, (I was at the turnaround of a two-way trip) I drove it. 15 minutes from my destination, and at about 80mph, all hell broke loose. I heard and felt a huge BANG. Saw my hood bulge up and fiberglass dust shoot up as something shot through it. Steam and smoke everywhere. Brakes very unresponsive and the vibration was terrible. I got it pulled over safely. When I opened the hood, I coud not believe the damage. It literally looked like a grenade went off in the compartment.(and I happen to know what that actually looks like!). The fan had disintegrated, leaving one blade on the hub. The other blades flew around the compartment and through the hood. Extent of damage was bad. Fiberglass work, hoses and wires sliced, brake pads contaminated, stripped water pump mounting holes. shroud destroyed, intake destroyed, blah blah blah. It was a very dark day for me! :eek: :U
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