Best Replacement Water Pump?

Mine came with two and I just matched the old one, skimmed it with RTV and installed it. Don't make it more complicated.

Don't forget the torque values. Some are in inch lbs not foot lbs.

-Mac

Hi Mac, I hope you're doing well. I bought the new version of the water pump (68382489AA) as a set about six months ago. Now it is leaking.
https://www.summitracing.com/parts/...IjzwQGvUUAwg1nEUeFS-CV88Rk3yylTGsodMJd85nVuPO


umw-mck1074_xl.webp


I would like to 'downgrade' to the old version. Does the new clutch fit the old version, and do I need to buy another clutch? Or a new 'old version' set?
The old version
04626054

SK1101090_1.webp
 
The fan clutch threads should be the same size.

Also take a look at the Flowkooler water pump. Don't pay too much attention to the flow claims, but it's a good water pump at a decent price, cheaper than Mopar. It should flow as well if not slightly better than the newer OEM style with the plastic impeller.
 
I installed a Hayden 2771 fan clutch in March along with a Flowkooler water pump . I honestly can't hear much difference in noise . I let it idle for over 30 minutes sitting in the sun with 91 degree outdoor temperature with the AC on . The temp gauge stayed just below the 210 mark and the AC was blowing cold . We took it for a short trail ride and the temp stayed the same and the AC was nice and cold . It actually runs cooler sitting still or putting down the trail than at highway speed. Highway speeds it runs 210 or just to the right of 210 but still touching it . Air conditioner blows nice and cold at all times .
I would say this combo is a win , only time will tell about durability .
Koyorad A2102 radiator
Hayden 2771 fan clutch
Flowkooler water pump
Robert Shaw 195 thermostat
 
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It actually runs cooler sitting still or putting down the trail than at highway speed. Highway speeds it runs 210 or just to the right of 210 but still touching it .

It may be the engine RPM at highway speeds is generating more heat. My classic car does that - 70 MPH is 3400 RPM, and in 110 ambient temps with the AC on the coolant temp starts going above 200.
 
I installed a Hayden 2771 fan clutch in March along with a Flowkooler water pump . I honestly can't hear much difference in noise . I let it idle for over 30 minutes sitting in the sun with 91 degree outdoor temperature with the AC on . The temp gauge stayed just below the 210 mark and the AC was blowing cold . We took it for a short trail ride and the temp stayed the same and the AC was nice and cold . It actually runs cooler sitting still or putting down the trail than at highway speed. Highway speeds it runs 210 or just to the right of 210 but still touching it . Air conditioner blows nice and cold at all times .
I would say this combo is a win , only time will tell about durability .
Koyorad A2102 radiator
Hayden 2771 fan clutch
Flowkooler water pump
Robert Shaw 195 thermostat

Hi Harold, thanks again....
The Flowkooler water pump is on the list.
The Robert Shaw 195 thermostat has been installed for six months now. It's the best thermostat I've installed in the last 20 years. Everything else is borderline (Gates, motorcycle, etc.).

Today, in a four-hour "operation," I removed a water pump (which had only been in the Jeep for six months, US Motor Works, the gasket was already broken – it's junk...) and reinstalled the same water pump (old version) with a new FelPro gasket (new version). For everyone's information: it fits perfectly because the four mounting holes in the gasket are identical. I used Dirko HT sealant on the top and bottom, and everything works great. No more leaks.

The broken seal from US Motor Works:
photo_2026-05-15_15-18-31.webp


photo_2026-05-15_12-37-25.webp


A new FelPro gasket (new version) with an old water pump - fits well...
SFL_35629_P04_TOP.webp


I'm ordering a Flowkooler water pump now - this combination will have to hold up until then...
Thank you to everyone who responded so quickly. Without you, I would have had to sell my Jeep years ago...
All the Best from Hungary
Edgar
 
Hi Harold, thanks again....
The Flowkooler water pump is on the list.
The Robert Shaw 195 thermostat has been installed for six months now. It's the best thermostat I've installed in the last 20 years. Everything else is borderline (Gates, motorcycle, etc.).

Today, in a four-hour "operation," I removed a water pump (which had only been in the Jeep for six months, US Motor Works, the gasket was already broken – it's junk...) and reinstalled the same water pump (old version) with a new FelPro gasket (new version). For everyone's information: it fits perfectly because the four mounting holes in the gasket are identical. I used Dirko HT sealant on the top and bottom, and everything works great. No more leaks.

The broken seal from US Motor Works:
View attachment 688707

View attachment 688708

A new FelPro gasket (new version) with an old water pump - fits well...
View attachment 688709

I'm ordering a Flowkooler water pump now - this combination will have to hold up until then...
Thank you to everyone who responded so quickly. Without you, I would have had to sell my Jeep years ago...
All the Best from Hungary
Edgar
Your welcome . I wound up installing the thermostat in my Chevy truck:) .
Glad to hear you have been able to get the necessary parts .

I believe I used a Felpro gasket on the water pump and thermostat housing . Next on my list of things to do is a Felpro valve cover gasket .
 
Are there two different gaskets for the water pump? When I order a water pump with a seal from RockAuto, the gasket looks different than when I order just the gasket separately...that's kind of strange, isn't it?

Is this the older one?
View attachment 688618

And this the newer one?
View attachment 688619

And which one should I install? I had a new water pump installed six months ago... it's already leaking.
https://www.rockauto.com/en/moreinfo.php?pk=11956081&cc=1431777&pt=56846&jsn=4

US MOTOR WORKS MCK1074

Is the clutch compatible between the two models? Are the holes for the four screws the same distance apart?

The first gasket is for the early style pump. The second gasket is for both early and late pumps. The extra holes are to make it work for either.
 
It may be the engine RPM at highway speeds is generating more heat. My classic car does that - 70 MPH is 3400 RPM, and in 110 ambient temps with the AC on the coolant temp starts going above 200.

Pretty much.

The heat generated by the engine is directly proportional to the power being generated, which increases with the cube of speed.
The heat rejected by the radiator increases quickly as the airflow becomes turbulent but then the gains taper off as speed increases further.

Starting at idle, we have some generation but no rejection, which is why we need a fan or else it'll overheat.
As vehicle speed increases there's a point where the heat rejection exceeds the heat generated, so no fan is needed.
Eventually the curves cross again. We just hope it happens at a speed exceeding where we ever cruise at (and for any new vehicle, it does, but that point will happen at lower speeds if the radiator is undersized or the cooling system is contaminated, etc.)

1779154262380.png
 
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