Water pump

EDUARDO VALDES

MEMBER
2005 JEEP GRAND CHEROKEE
5.7L
V8
4WD
AUTOMATIC
117,826 MILES

Recently replaced the heater core and thermostat. Vents blowing cold air, took it back to mechanic and he says he got the air pockets out. Still doing the same thing, he called a Jeep technician to come take a look and he says he’s 80% sure it’s water pump needing to be replaced. I took it in originally to get the nasty antifreeze smell fixed from the leaked heater core. It was blowing hot/cold just fine no issues besides the smell.
I get it back and now i'm having issues with everything else as explained above. Blowing cold air on idle. It will only blow hot when I’m driving (accelerating) I just think it’s weird that the water pump gave out.

1 Reply

CJ MEDEVAC

MECHANIC
11,005 POSTS

I looked up your vehicle/water pump at "Advance Auto Parts"

The one pictured that I could see the impeller in showed that it was plastic.

I'm going to show you a pic from another vehicle with a bad plastic impeller. It's symptoms may differ from yours.

Keep in mind that vanes might be hanging on the body and stopping or slowing the impeller down. This maybe being caused by the plastic no longer being fully attached to the shaft.

I have other pics where pieces of the plastic are missing (pic 2 is a Taurus).

Sometimes without taking the water pump off, you can diagnose this possibility on water pumps by removing the drive belt and the radiator hose, pushing something like a long nail into the hole for the radiator hose and manually rotating the pulley with your fingers.

If you can hold the impeller still with the nail, and the pulley (shaft) still can be rotated, you can probably bet the impeller is not attached.

A really bright light and an inspection mirror might also let you check for damage.

The Medic

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