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new pump now overheat!!

M

mudrat

NAXJA Forum User
Location
scappoose
hello, 94 4.0 HO. i put in a new water pump, heater control valve, and belt now i have some major overheating. i have checked everything and checked the valve routing many. i have no heat even though it pretty much goes straight to redline.ithe system has coolant in it. i pulled the coolant sensor to see if there is water runiing and only have steam could it be that the thermo has slammed shut???please help
 
When you purchased the water pump did you verify that you were given the correct pump.
There are two pumps available for the application; standard rotation and reverse rotation; yours should be stardard rotation.
 
Last edited:
WHOA----- The correct rotation is REVERSE--- there should be a "R" on the impeller.
 
CharlesS said:
If you check NAPA online they list the Standard rotation as there recommended pump. This could be where his problem is.....
Click to expand...

Ok Charles,that is where the problem lies---On my 96 is a NAPA #42004 water pump.NAPA ,as you stated, calls this a "standard rotation" pump.It is reverse rotation,as is standard on our XJ,s

Well thats as clear as mud,,,,,,,,:thumbup:
 
I would probably pull the thermostat out and drive without one for a day to see what happened. I've had several bum thermostats over the years. Funny how they can run forever with no problems and then they drive you crazy. Hey! Sorta like my Ex!!

A couple of years ago I put in a HESCO high flow thermostat housing and water pump, and a high flow thermostat from somewhere highly recommended (forget just now) and had same problem. Went down to Nappa and bought a stock thermostat and the problem was solved.
 
Do you even need to bleed an open system? Wouldn't it be self-bleeding?
 
Fish'nCarz said:
Do you even need to bleed an open system? Wouldn't it be self-bleeding?
Click to expand...

It should "self bleed" after three or four cycles of hot/cold/hot. The air should work out into the overflow, and if there is enough spare coolant in there it'll get sucked in and displace the air.
 
ParadiseXJ said:
It should "self bleed" after three or four cycles of hot/cold/hot. The air should work out into the overflow, and if there is enough spare coolant in there it'll get sucked in and displace the air.
Click to expand...

And this may be your only issue. If you're radiator/engine block coolant levels haven't reached capacity, in this hot weather it could negatively inhibit your engine cooling system from cooling properly. It takes a number of trips for the coolant to get back to full levels.

A trick I learned from a mechanic on our XJ's is to fill the system from the heater hose that attaches to the thermostat housing? I don't remember. I have to go look but its the heater hose that is at the highest point on the block and then while holding the hose above the level of the engine using a funnel pour engine coolant in from there. Filling the radiator is not going to fill the block until as mentioned above it has an opportunity to heat and cool a number of times to suck down the overflow bottle.
 
ParadiseXJ said:
So....reverse is standard....and standard is wrong...right?

Obviously written by a government official.

:huh:
Click to expand...
Remember that the 4.2L was around first and ran a Vbelt system and that was standard. Even the 2.5L in the XJ started with a Vbelt. When they converted over to serpentine belts, the routing necessitated reversing the pumping direction.

The screwy thing is that they didn't change the pump body at all, only the impeller. That yields a crappy efficiency, but I guess it pumps enough coolant to make it work but if they had changed the arrangement of the housing, they could have gotten a lot more flow.
 
CharlesS said:
When you purchased the water pump did you verify that you were given the correct pump.
There are two pumps available for the application; standard rotation and reverse rotation; yours should be stardard rotation.
Click to expand...

Been digging into the hub height and Rotation issue, at Rock auto today. I am starting to think the "standard" they list is meant as reverse rotation when that is the OEM standard? So now I am wondering if there ever where any forward rotation pumps? Were they ZJ pumps? As the 2.5 L 4 banger is taller, and also is listed as reverse rotation. This standard versus standard reverse, versus reverse is just as clear as MUD!!!
 
I just got confirmation that Bosch 97082 water pump is ALSO reverse rotation!!!!! It is also the correct hub height for the XJ 4.0 engine!!!
 
The real way to tell is to look at the impeller on both pumps and make sure they are oriented the same way.

As for bleeding. It is sometimes necessary. I just had to park mine downhill and pull the temp sensor at the rear of the head. It ran nice and cool down the highway but as soon as you stopped at a light, within 60 seconds it would jump to 240. It never really overheated to the point that the cap vented. The real thing to note is that if there is water on the sensor, you can't heat the water that many degrees in a minute or less. It varies because the sensor is in air not water if there is a bubble.
 
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