How do i determine if i have a weak waterpump

I carried on a few weeks back about no heat in a 95 cherokee. ive got it to make heat but i needs to be above 2000 RPM or its just luke warm. Im thinking i need a good flushing and or a new waterpump. Is there some way to determine if the pump isnt pumping like it should be? 145000 miles. i didnt get any maintenance records with the vehicle

Have you replaced the thermostat? Is the engine temperature normal? Gas mileage normal? A cooling system flush can’t hurt on any vehicle of that age and mileage.

PS I enjoy your posts often. No BS and often very clever.

Thermostat seems to work proper as i can watch gauge rise and fall with apparent open n close. mpg is same as always. and Thanks :slight_smile:

Try flushing the heater core. Very easy on this vehicle.

just pull the hoses off and force water through? Should i go normal circulation or backwards or does it matter? Thanks

Go both ways and start out with slow water flow and slowly speed it up just in case you do have an obstruction you wont blow the core apart.

How is your engine temp? If the engine heats up to normal but blows no heat, think of these. The actuators or actual vent controls for heat control be it vacuum or electric control could be failing. Some cars also have a separate control for allowing coolant flow to the heater core.

I think you may be on to something here, it is not normal to see the temp gague move around so much that you interpet it as the thermostat opening and closing. Since you are having trouble with the engine temp I would pull the pump and check the impeller, since you now have the pump out it gets replaced.

temp is good and blows heat but not at an idle

jeep has 4 speed heater fan. if i start n let idle it Does blow heat on 2 The higher i go with the fan speed the less heat i get. The gauge goes from 180 to 210 or there about. Is it not normal to see this with the opening and closing of thermostat

It is not normal to see the temperature of the engine moving around in a 40 degree range, this movement is a sympton of a greater problem.

It took me 2 years to figure out my fan speed did not work n settings 1 or 2, 3 to 5 was fine. We were cold or hot, but at highway speed it seemed fine.

Assuming the temp gauge reading is not fluctuating due to low coolant and since you refer to to heat but not at an idle maybe there’s a problem with the blend door.

I do not know if the door on this model is vacuum operated but if it is that is something for consideration.
With the engine fully warmed up, and coolant full, touch both heater hoses. Both should be hot. If they are and you have no heat then the blend door is suspect anyway.

mine fan blows air at all speeds

The blend door is vacuum operated. However if the core needs flushed would this not cause the hoses to be different temps? I checked them long ago when i had my original problem and they are not the same temp

I’m not sure your thermostat is OK, replace it. Not too expensive and you can see if it helps.

If you can access the in and out heater core hoses, remove them and check for easy water flow through the heater core. If the flow isn’t restricted it probably isn’t the heater core. Perhaps you can clamp on 4" sections of clear hose into and out of the heater core temporarily to get a visual on what is happening when you operate the heater controls. You might get to see good flow, or not, and perhaps you can see if there is some air (bubbles) in the system.

At 145,000 miles you are coming due for your second timing belt change, and the water pump is inline to that part. The cost to replace both is around $700. Without any records you might want to assume that you are driving on the original belt. If it goes, your valves will be damaged and the repair will be much higher than the value of the truck. The cost to replace the timing belt and water pump is mostly labor; the parts are cheap. Replace the water pump and the timing belt. The old fluid will be replaced in the process.
It might be worth it to have the shop flush the system with the heat on before doing any repairs. They would then drain the system, replace the old parts and add new radiator fluid to your system.

Have you checked the coolant level in the radiator (not the recovery tank} can cause exactly the symptoms you have.
No Jeep Cherokee had a timing belt.

Just curious. Which engine in a 1995 Jeep Cherokee has a timing belt?

You can’t “flush” lime deposits (or any deposits) out of a radiator or heater core…These deposits are not soluble in water…If the core is composed of brass-copper-lead you can (by using the disconnected hoses) fill it with muriatic acid and let it sit overnight. That will dissolve the deposits…The acid will not attack the metals I mentioned. If your core is aluminum and plastic, do NOT use this method…Read all the warnings on the acid bottle and follow them. Rinse out the core with a weak baking soda solution to neutralize the acid when you are done…Or replace the core with a new one…

You can test your pump by removing the inflow hose from the core and holding it in a bucket, gauge how forceful the flow is when the engine is started…It should have considerable force…Another place that can plug up, the hose fitting on or near the thermostat housing can corrode shut…