Which pump is the correct one?

Running warm at idle, so I thought I'd try a new pump. The old rusty one is what I took off and the new one is a Gates. The counter man at NAPA swears he sold me the right one, but I'm not sure about that. The engine in my Jeep is a 4.2 with a casting date in 1984, probably the original engine, it has a V belt. Which pump is correct? Thanks!

 

Each water pump in the pic has a distinct impeller direction. I can only tell you it's very important to use the correct one! Someone more mechanical will probably chime in.

 

As I recall hearing, The v-belt impellers have a different rotation than the serpentine belt.

 

Hey duff! So the way Jeep did it is the v-belt rotation is standard which is the new pump NAPA sold you and the serpentine belts are reverse rotation which is the old one you took off. Hope that helps.

 

So, the coolant was going the wrong direction in the engine? The guy I bought it from had a lot of engine work done and most of it needs redone. I did some research on line, watched some videos, but came up with conflicting data. There seems to be lots of confusion and misinformation from the manufactures on the 4.2 water pump. I did order and install a new pump for a 1985, V belt 4.2, I received Omix # 17104.13, the vanes went the same direction as the old rusty one I took off, so I assumed it was the right one. Still had cooling issues, and I wasn't happy with the poor casting of the Omix pump, so back on line I read that the correct Omix pump for my Jeep is 17104.04. So, I Ended up going to NAPA yesterday to look at a GATES pump, that's when I discovered I may have had the wrong pump the whole time, I bought Gates TWP 43001 for $35.49. As a side note, I had to grind the casting on the Omix pump to clear the timing cover, ( wrong pump clue and I missed it) run a drill thru a couple of the bolt holes, heater hose outlet too large to attach the 3/4 hose. The heater hose outlet on the new Gates, easily accepts the 3/4 heater hose and the casting looks very nice. I'll install today and post the results. Thanks for all the help!!!!!!!!!

 

As they say hind sight is 20:20....should now get proper cooling with the Napa wp

 

Think of it more as the water pump you took off was scooping the coolant instead of pushing it. It still flows the same direction but moves it very inefficiently which is why it was over heating. Of course there can be other factors but this is a very good start.

 

New water pump is on, no more coolant puking past the radiator cap, all the heater hose are warm, not cold like yesterday! I let it idle for 15 -20 minutes then brought the rpm up to 2,000 for bout a minute, did that several times everything is good! I did the Jim Beam trick and drilled a 1/16 hole in the thermostat to let any air bleed out. Here's a picture of both water pumps, the rusty one came on the Jeep and the black one is the new crappy Omix I installed. Let me tell ya, the new Gates water pump looks and fits great with no grinding needed and the 3/4 heater hose went on easy like it should, it's the one to buy. On the Omix pump, I had to warm up the heater hose to get it over the nipple and when I changed out pumps, had to slice the hose to get it off the nipple. Thanks for all the help, I really appreciate that! PS I'm waiting for some linkage parts, so I don't have the Weber hooked up completely, just enough to get it running ,I'll bend a hard line for the fuel and hook up the rest. Thanks!

 

Here's one of the videos I watched when trying to figure out the right pump. Watch the whole video and read the comments that were left.https://www.youtube.com/watch?v=3IDX1G_vzSE

 

Nailed it. Also, be careful if you replace alternators. First year with the serpentine belt the nut that holds the fan on the shaft was the wrong way for the rotation. More than one, including mine spun off and ended up in the radiator.