[IzTheWiz]

Hello all,
 I just changed the water pump in my Cforce 500 now it seems to be over heating. I originally changed the pump with an new Oem part because of a small leak from the weep hole. Before I even installed the new one I compared it to the old one just to make sure it was the same. Once installed I topped off the coolant, oil, and made sure I purged it for any air pockets. After running for a few minutes it starts to overheat and the fan no longer kicks on. I also “jumped” the thermo switch thinking that possibly went bad but the machine still over heats even with the fan continuously running. Has anyone ever seen anything like this before or have any ideas of what I could be missing?

[NMKawierider]

One quick question: Is the radiator getting hot?

[IzTheWiz]

Honestly I didn’t even think to check. I’ll run it for a little bit and see.

[NMKawierider]

If it isn't that means there isn't any flow. Either the pump isn't pumping..because of an issue with the impeller or drive connection or the impeller is in an air pocket... or there is something stopping the flow..like s stuck thermostat or lines switched.
If it is getting hot...that's a whole different set of possibilities.

[IzTheWiz]

It’s pouring outside right now so I haven’t had a chance to check yet. If there is some type of issue with the flow or and air pocket would this affect the fan from kicking on? Would the coolant pressure somehow trigger it? The fan usually kicks on when the temp reaches 3 bars but now it’s not doing anything at all.

[NMKawierider]

It’s pouring outside right now so I haven’t had a chance to check yet. If there is some type of issue with the flow or and air pocket would this affect the fan from kicking on? Would the coolant pressure somehow trigger it? The fan usually kicks on when the temp reaches 3 bars but now it’s not doing anything at all.

The fan switch or thermoswitch is on the radiator and the gauge sensor is on the engine. It can show bars but if it's cool at the radiator, the fan will never come on.

[IzTheWiz]

That actually makes an excellent point and explains why it didn’t cool down even after I jumped the thermo switch to make the fan stay on!

[IzTheWiz]

Update: I ran it until the temp bars were two away from the red. The radiator never actually got hot just slightly warm which I suspect is residual from the trans cooler mounted in front of it. Just out of curiosity I carefully opened the cap and there is pressure in the system but even the coolant that leaked out was just about room temperature.

[IzTheWiz]

Bump

[NMKawierider]

The system will pressure from the heated coolant at the engine and the farther away it gets the less heat is conducted . So..you have no flow. Something is wrong with the pump as even if the thremostat was stick shut, the small hole in the thermostat to bleed air off would have circulated some to the radiator. You have none...so need to take the pump back off and see what's up.

[NMKawierider]

I assume your water pump is like this one. When out check the drove end for any issues and the receiver. Even bump the starter to ensure the engine side is turning. Then take it apart.


This is the drive key that sometimes brakes. It droves the pump so take a close look once it's out:

[IzTheWiz]

That’s the same water pump. Before I remove the water pump again should I try it in gear and see if that helps with the coolant flow? Until now I’ve only tried it parked in neutral. I looked at everything when I originally took it apart and it all seemed ok but then again I wasn’t aware I had a problem until I put it all back together.

[NMKawierider]

That’s the same water pump. Before I remove the water pump again should I try it in gear and see if that helps with the coolant flow? Until now I’ve only tried it parked in neutral. I looked at everything when I originally took it apart and it all seemed ok but then again I wasn’t aware I had a problem until I put it all back together.

It won't make any difference..not driven off any transmission shaft.. but you might take and squeeze the lines to see if maybe there is an air pocket around the impeller you can work out. DON'T let it get over 4 bars. These CFM engines can't take being overheated much.
If you can, just take the outer cover off and see if you can spin the impeller. You should not be able to.

[IzTheWiz]

That’s the same water pump. Before I remove the water pump again should I try it in gear and see if that helps with the coolant flow? Until now I’ve only tried it parked in neutral. I looked at everything when I originally took it apart and it all seemed ok but then again I wasn’t aware I had a problem until I put it all back together.

It won't make any difference..not driven off any transmission shaft.. but you might take and squeeze the lines to see if maybe there is an air pocket around the impeller you can work out. DON'T let it get over 4 bars. These CFM engines can't take being overheated much.
If you can, just take the outer cover off and see if you can spin the impeller. You should not be able to.

I think you might be right about it still having an air pocket somewhere. I’ve topped the radiator and overflow bottle off twice and I just looked and the overflow is empty again. I’ll try to top it off and run it again tomorrow and see if that works.

[Lasaanda]

I'm having similar issues ... what was your fix?