I have an overheating issue due to my electric waterpump not pumping water. The car will run fine for awhile and temps stay cool, 180 degrees or so. Then instantly the temps start shooting up quickly to near 220 and I shut down.

I have found that my waterpump is losing its prime. It wont pump water sometimes but other days its working just fine.

Last night i took the car out for awhile and was doign some tuning/break in on the new motor. Tonight i was doing the same thing but this time it overheated on me because water pump was not working. I let it cool down and started driving again and the waterpump magically was working again, temps back down to 170's.

Thankfully i wasnt stranded on the road for more than 20 min or so while it cooled down.

Is this due to an air leak in the system/air bubble? I do have a minor leak at the inlet hose barb connection for this electric pump, so my guess is it is sucking air through that leak point and not able to pump water anymore

 

It almost sounds like you are losing cooling system pressure.
My car did some thing like that with the cooling system bypass blocked off but it got a lot hotter than 220.
I also thought the same thing, that my pump wasn't pumping. But it was other stuff.
Also 220 is pretty normal. Before I rebuilt the entire cooling system in my car 220 was normal operating temp for many years.
I think when I put aluminum heads on my car the 195 thermo stat is going back in and operating temp will be back up to 200-220.

Did you wire up your cooling pump to run with the engine off if you wanted it to?

 

yeah this pump is wired to run whenever i want it to. And its not pumping water when this happens, i verified this by opening the cap to the rad and watching the water NOT move.

220 is not normal for this situation because its cruising at 170's 180s and in seconds starts to skyrocket to 220 before i shut down to save the motor. If i left it go it would go to redline on the gauge i'm sure which is over 250+

I do think i'm losing pressure and I am wondering if its due to that leak by the pump

 

Yeah I noticed these pumps can't prime their self worth a 1981 ford mustang.
When I got my proform pump I wired it to my jump pack and stuck it in my swiming pool to see how much water it moved. I had to dunk the pump to prime it.
When its not pumping make sure you have voltage going to the pump and don't have an open wire or connection some where.
I soldered all my connections for that reason.
When my engine is off and my pump is turned on I can feel and hear it turning and vibrating a little.
If you have a heavy duty or standard thermostat it will appear that no coolant is moving when the thermostat is closed. It should be closed at any thing below 160'f or so.
I have a high flow thermo so some coolant always moves through the radiator even when cold and that sucks during the winter.
You still have your coolant bypass hooked up right?
Because now it really sounds a lot like what my car was doing when I blocked it off.

 

no longer have coolant bypass. I have a 170 degree thermostat from TPIS that i drilled 4 holes in around the edge to allow some flow even when shut.

Like i said, i can see water move in the rad with cap off when its pumping. When it is not, you can hear the pump run but nothing is moving, so i dont think my wiring is loose but I'll have to double check that as wiring problems have plagued me in the past.

I'm gonna tear it down and retighten/seal that threaded inlet connection to make sure that leak isnt causing my problems


Also, is it a problem that my thermostat outlet neck sits higher than the radiator inlet?

 

Trust me you need a coolant by pass.
Oh yea from what you told me in the last 2 posts you have the same problem I had, to include every last fine detail when I ran no bypass.
The funny thing was I didn't really have any problems with the mechanical pump and mechanical fan, it only suddenly appeared after I converted to electric coolant pump electric fans and drove on the high way. It was fine in the city at lower speeds.
I believe the electric pumps were designed to flow 35gpm with both a thermostat and bypass, if you block off the bypass it doesn't flow enough.

I think all camaros but the V6's have their thermostat outlet neck sitting higher than the radiator inlet. Its not a problem if you very agressively burp and twist and squeze the hose to push out bubbles while the coolant is flowing.

 

The bypass doesnt do anything except run hot coolant to the throttle body for winter air or are you talking about the heater core water valve? The water valve only bypassed water from motor to heater core for heat when needed. If not it went back to the rad. TB bypass from what i recall ran coolant from part of the manifold to the throttlebody then back to the manifold so how is that doing anything since its in the same flow path?

I have neither of those bypasses and dont understand how the lack of a bypass would cause this issue.

I also have no way to add the bypass back in since i'm running a LS1 throttle body and it has different connections for the TB bypass.

 

I forgot about the TB bypass, you don't need it.
I was talking about bypass used for the heater.

I didn't understand how not having a bypass would cause this problem either, the only reason I figured it out is I have my main engine coolant bypass hooked up but I have a 1/4 turn ball valve installed in line. When I had this problem I very quickly figured out it only happened when the valve was closed and it very quickly went away when the valve was opened.

 

interesting..i am gonna play around with it tomorrow alittle since i failed to get to it tonight like i wanted to.

With all my turbo stuff in the way, i really dont see how i can add a bypass. I'll try fixing my leak and seeing if that helps. I also think my system may not be 100% full. I looked at the rad level and it was full, but when i turned the pump on, it sucked the water level down abit and when shut off, it went back to full, so its like water was backing up. I am wondering if I need to fill the system again while its running to ensure its filled up right.