I recently purchased a MasterPro water pump for my 87 V6. The mobile mechanic arrived to install it and as we started prep, to remove the heater bypass nipple that's used on the 85 and 86 V6, we noticed the nipple was cross-threaded into the pump. Tilted heavily toward the engine side of the pump. I had to send the mechanic home and returned the pump to the store.

They ordered another that came in the next morning, so down I go to make the swap. This time, I inspected it before leaving the store. Same thing. Cross-threaded and tilted inward toward the engine. The clerk called their warehouse and had someone pull another. Same thing. It was cross-threaded, too. These are new pumps, not rebuilt.

I purchased the MasterPro for several reasons. One was because it comes with a gasket. It seems the gasket isn't available without buying a kit. The clerk told me to keep the gasket from the one I had, since the returned ones would be marked defective and not put back on the shelf. I ordered another one, identical but it doesn't have the nipple installed or a gasket.

sorry to hear your problems. you should be able to remove your original fitting and install in new pump my last one from Napa was that way. Make sure you use a little pipe sealant and don't overtighten fitting as it is not hard to crack the pump housing. Good luck sleek

Hope you get/got it sorted.

I bought a thermostat/housing for another car, at O'Rielly. Lasted a year, almost to the day, before it started overheating again.
Replaced it with a Gates piece, that I ordered off of Amazon. We shall see.

I was surprised to discover all this crap about O'Rielly's. I always considered them a notch above Autozone and maybe Advance. (I refuse to use the Autozone near me, simply because of their business ethics. Long story, for another day.)

[This message has been edited by Raydar (edited 09-07-2025).]

quote Originally posted by Raydar: Hope you get/got it sorted. I bought a thermostat/housing for another car, at O'Rielly. Lasted a year, almost to the day, before it started overheating again. Replaced it with a Gates piece, that I ordered off of Amazon. We shall see. I was surprised to discover all this crap about O'Rielly's. I always considered them a notch above Autozone and maybe Advance. (I refuse to use the Autozone near me, simply because of their business ethics. Long story, for another day.)

The AutoZone in Winder and Dacula have very poor service. I had been driving all the way to Flowery Branch when I wanted an AutoZone product. O'Rielly here in Auburn has been very good. In the long time I've been using them, I've only had one previous issue, and that was a coolant recovery tank cap that was so flimsy that the threads wouldn't hold when tightened down. They have always matched prices of any other parts store. When NAPA would only sell me a case of 1/4 inch butyl rope to install the new GT taillight lenses, O'Rielly matched the per roll price and sold me the one roll. Same brand.

AutoZone recently opened a store here in Auburn and I've ordered online for pickup but never had any other eyeball contact business with them. I don't know how their customer service is, yet.

Anyway, the new pump comes without the nipple. It's a different brand. I'll just pick up a pipe plug at the hardware store.

I believe you're aware to buy a water pump with a METAL impeller...
Many good brands are now "no longer available"
Beware Gates #43092 – made in China, the description at RockAuto says it has a cast iron impeller, but in fact it’s plastic

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Original Owner of a Silver '88 GT
Under 'Production Refurbishment' @ 136k Miles

The fact of the matter is that every month at my local AutoZone store there is a palate of returned parts. Chinese parts are mostly what is sold at Autozone because the supplier was probably the lowest bidder of the day. Some name brand parts are still mainly good like Bosch, AC Delco, TRW, Standard, NGK, and Delphi but with the "off brand" stuff, its a gamble..
Over in China it goes like this. The worker on the product line says to the supervisor "we have some parts here that don't need spec what do we do"? The supervisor comes by and says you know what to do, ship em.
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" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

[This message has been edited by Dennis LaGrua (edited 09-09-2025).]

quote Originally posted by fierofool: I recently purchased a MasterPro water pump for my 87 V6. The mobile mechanic arrived to install it and as we started prep, to remove the heater bypass nipple that's used on the 85 and 86 V6, we noticed the nipple was cross-threaded into the pump. Tilted heavily toward the engine side of the pump. I had to send the mechanic home and returned the pump to the store. They ordered another that came in the next morning, so down I go to make the swap. This time, I inspected it before leaving the store. Same thing. Cross-threaded and tilted inward toward the engine. The clerk called their warehouse and had someone pull another. Same thing. It was cross-threaded, too. These are new pumps, not rebuilt. I purchased the MasterPro for several reasons. One was because it comes with a gasket. It seems the gasket isn't available without buying a kit. The clerk told me to keep the gasket from the one I had, since the returned ones would be marked defective and not put back on the shelf. I ordered another one, identical but it doesn't have the nipple installed or a gasket.

sorry to beat a dead horse here and revive a bit of a older thread but its almost every waterpump for the fieros and s10s currently, its horrible quality control and i was chasing a water leak and overheating issue for months on the 88 before gave up. tearing down the blown up engine and what do i find? that the stupid cast iron impeller spins on the shaft moving very little water under higher rpm/load and that the gasket was the wrong shape from the start.
do NOT buy the masterpro or any other water pump thats not from gates at this point. i keep having the pulley boss, impeller or something else go wrong and cost me alot more money and time....and several radiators in the case of the s10....

quote Originally posted by Raydar: I was surprised to discover all this crap about O'Rielly's. I always considered them a notch above Autozone and maybe Advance. (I refuse to use the Autozone near me, simply because of their business ethics. Long story, for another day.)

I've got time for a story *popcorn*

quote Originally posted by cartercarbaficionado: ... tearing down the blown up engine and what do i find? that the stupid cast iron impeller spins on the shaft moving very little water under higher rpm/load and that the gasket was the wrong shape from the start. do NOT buy the masterpro or any other water pump thats not from gates at this point.

Wow! Usually, the "loose impellers" are the plastic ones - and that seems to happen after things warm up. I've been here forever, and this is the first time I've ever heard of a cast iron impeller spinning.

quote Originally posted by Raydar: Wow! Usually, the "loose impellers" are the plastic ones - and that seems to happen after things warm up. I've been here forever, and this is the first time I've ever heard of a cast iron impeller spinning.

It wasn't the impeller that was loose. The whole shaft could be wiggled around. The impeller was still solidly attached. There was about 1/4 inch side to side movement of the pulley. The bushing or bearing must have just disintegrated.