[GarScramb]

My Scrambler has a 258 and does NOT have a serpentine belt. I replaced my water pump and noticed on the one I pulled out that it had "REV" stamped on it. My understanding is that "Reverse Flow" pumps should only be used on systems that use a serpentine belt. I replaced the pump with a regular flow pump, as per the manuals.

Since replacing the pump and radiator I haven't overheated again, but the temp gauge seems to run on the high side (almost out of the green sometimes).

Question: If I had the wrong flow direction pump in, would I see the thing overheat really fast or could the result just be a hot running engine like I am seeing?

I am guessing that if the answer is that it will overheat, then I must have some blockage inside my engine block causing the hot running engine....?

Any advice?

Thanks in advance.

 

[CSP]

The first thing I would do is get a gauge with temperature markings on it. Who knows what temp the "green area" is on your stock gauge. For that matter you could have a bad sender also. Start simple and confirm your suspicions before jumping to any conclusions.

 

[GarScramb]

Good point, and I will do that. The thing is, this thing has had an overheating problem for a while now. And so far, the gauge has been pretty accurate. When the needle leaves the green, the cap starts steaming soon after.

What I really would like to know though please, is this.

Is it possible at all, to have a regular belt (non-serpentine) and a "Reverse flow" water pump on a 258?

 

[GPERX4]

Do you have a two or three row radiator,do you have a Warn 8274 on the front, are you driving 70 mph? When I had a two row radiator with the winch on the front and drove 70+ mph for awhile it would heat up. A three row radiator solved the problem.

 

[GarScramb]

Nope. No winch and just driving 20-40ish MPH around the neighborhood.

As for the radiator, well, I kind of screwed up there a little. I bought a new one and put it in. Only I just got a factory replacement and it's most likely a 2 core. Need to look into the OEM, but almost sure it is 2.

 

[JeepinIan]

Get a friend that has a heat gun and get the temp of the neck of the rad coming from the thermostat. Not the hose, but the metal neck.
Then check the neck at the output side of the radiator. There should be a 10* diff. If more, the water flow is to slow, or the radiator is too big. If less, there is a blockage of air flow, not enough restriction on water flow, or radiator too small.

 

[Robert]

What I really would like to know though please, is this.

Is it possible at all, to have a regular belt (non-serpentine) and a "Reverse flow" water pump on a 258?

Both styles are made for the 258. The V-belt style is the standard rotation model, the serpentine belt style is the reverse rotation. If your pump is marked "REV", you have a reverse rotation pump, you need to remove it, return it to the parts store where you purchased it, and promptly insert said pump into the rectal area of the dumbass that sold it to you.
Good parts stores (not Checkers, Kragens, Autozone, etc...) will ask if your Jeep uses V-belts or serpentine when selling a water pump. They may ask if you have A/C or not, as this is supposed to be the determining factor in V or serpentine, but I have seen CJs with serpentine belts, and just an idler where the A/C should have been. So you still have to specify V-belt or serpentine.

 

[GarScramb]

No. Let me clarify.

I HAD a pump with "REV" stamped on it when I pulled it off. The parts store definitely did ask that question, and I knew the difference from Chilton's. The parts store gave me the correct pump for a V belt (regular flow).

What I can't figure out is, why the REV pump was on there to start with. And, how did the thing run fine for the first year I have had the Jeep.

Also, thanks for the advice on where to take the temperature measurements. I'll give that a shot.

 

[DoubleBit]

Maybe already did this but you absolutely must have a good thermostat. Also be sure your fan shroud and clutch (if equipped) are good. To keep an engine cool three basic things are mandatory, no leaks, regulation, and air flow. Get those together and you be cool.