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-   -   New Water pump now overheated (http://www.jeepforum.com/forum/f12/new-water-pump-now-overheated-1467347/)

87yjrad 01-22-2013 08:50 AM

New Water pump now overheated
 
87 YJ, 4.2 radiator and heater core were leaking, so last week I put in a new heater core and had the radiator fixed. Installed a new thermostat and filled everything back up. Drove to work the next day and my water pump blew. I replaced the water pump with a new unit from Napa, not re-manufactured. Let everything set up for a day. Filled up the radiator yesterday and started it up. Usually the pump starts circulating immediately and you see the fluid in the radiator drop, but nothing like that happened. I let it run for about 20 minutes and the only thing that happened was the engine temp started to climb. The radiator didn't get hot and the top hose was still cool. It was like I wasn't getting any circulation at all. Do I need to fill up the engine block with fluid in order to prime the new pump or something? I have never had this problem before. Thanks for the help!

timatoe 01-22-2013 10:13 AM

Does your 4.2 have V-Belts or a Serpentine Belt?
What part number water pump did you get?

The reason I'm asking is because the V-Belts will use a standard rotation pump and the Serp will use a reverse rotation pump. Both will bolt on without issue, but one won't pump anything if it's on the wrong set up. My guess is you have V-Belts and were given a reverse rotation pump.

bigbossd1030 01-22-2013 10:28 AM

Quote:

Originally Posted by timatoe
Does your 4.2 have V-Belts or a Serpentine Belt?
What part number water pump did you get?

The reason I'm asking is because the V-Belts will use a standard rotation pump and the Serp will use a reverse rotation pump. Both will bolt on without issue, but one won't pump anything if it's on the wrong set up. My guess is you have V-Belts and were given a reverse rotation pump.

Yup, that's what I was thinking. I almost had that issue but caught it in store. The impeller will have an "R" stamped on it and "REV" on the body somewhere.

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jbolty 01-22-2013 10:28 AM

Quote:

Originally Posted by timatoe (Post 14832721)
Does your 4.2 have V-Belts or a Serpentine Belt?
What part number water pump did you get?

The reason I'm asking is because the V-Belts will use a standard rotation pump and the Serp will use a reverse rotation pump. Both will bolt on without issue, but one won't pump anything if it's on the wrong set up. My guess is you have V-Belts and were given a reverse rotation pump.

^^^ this. Or, the belt is not routed properly

87yjrad 01-22-2013 10:34 AM

its v-belts, I thought they asked me that at the Napa store, guess I will call them and see what I really got. Thanks guys, it sure sounds like what happened.

Mark05059 01-22-2013 10:48 AM

lots of times they get switched in the box. You need one with out the R on the impeller for V belts. Also you may be air bound at the t-stat if they did give you the correct pump.

87yjrad 01-22-2013 11:17 AM

Is there any way to tell for sure which one I got without removing it? I'll be upset if I remove it and then find out I have the right one and its just air locked.

Mark05059 01-22-2013 11:25 AM

so try getting the air out first... if it doesnt work then remove the pump

Opihi59 01-22-2013 11:47 AM

Try this for more information.

http://www.jeepforum.com/forum/f12/w...torial-893428/

Xpress 01-22-2013 12:01 PM

Does the T-stat have a small pinhole drilled into it from the factory? If not then you need to drill one, just a small 0.050" drill bit will be plenty big enough. This small bleeder hole allows any trapped air behind the t-stat to flow out and let coolant fill in the space.

Hot air alone will not open the t-stat, it takes hot coolant.

87yjrad 01-22-2013 12:08 PM

you know '87 was just a bastard year for a YJ. Those pictures show the water pump for a '87-90 that does not have the integral heater hose nipple. My pump looks like the CJ pump that has the casted integral nipple and is supposed to be up to '86 only. Dang '87 YJ.

87yjrad 01-22-2013 12:10 PM

thanks xpress, I will check that before I pull the pump off again.

87yjrad 01-22-2013 12:37 PM

the description of the two pumps available at Napa say the pump with the v-belt is Reverse rotation, now I'm confused, which is it?

The Tru-flow 43001 is for 1987-1990 4.2L with Single V-belt, standard rotation
the Tru-flow 42002 is for 1987-1990 4.2L with Ribbed Belt Drive, reverse rotation

I'm guessing I need the 43001 standard rotation, what do they mean between single v-belt and ribbed belt drive? why don't they call it a serpentine belt like every one else.

Opihi59 01-22-2013 01:48 PM

Do you still have your old/original water pump you removed. It suddenly has become very valuable. If you have it you can compare the fin configuration on the impeller to match up the right unit for your rig.

87yjrad 01-22-2013 02:06 PM

yeah, I wish. Of course I threw it in the trash that was collected yesterday morning. ouch! I had no idea this was going to be such a big deal.

Is standard rotation counter clockwise looking at the front of the engine?

Nope, sorry I got it figured out, standard rotation is clockwise looking at the front of the engine.


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