Native-SKO
Senior Member
- Joined
- Sep 12, 2015
- Posts
- 3,860
Here is a diagnostic/debug suggestion.
Take the lead that hooks up to the electric heater pump motor and connect it to another 12V device, even a light. Better if that device draws the same current as the heater pump motor. Then, you can run around town and flip the pump switch like normal and see if it has any affect on the overheating. If it does not, then you know it has to do with the pump. If it does the same thing, you know it is in the electrical system and NOT the pump.
Take the lead that hooks up to the electric heater pump motor and connect it to another 12V device, even a light. Better if that device draws the same current as the heater pump motor. Then, you can run around town and flip the pump switch like normal and see if it has any affect on the overheating. If it does not, then you know it has to do with the pump. If it does the same thing, you know it is in the electrical system and NOT the pump.
Jolly Roger bus 223
Senior Member
your pump main body casing should have an arrow stamped or cast in the mold indicating direction of flow.
they like to hide them on the bottom of the casing where you cant see most of the time.
but is your smart phone isnt stupid sometimes like mine?
turn on your camera reverse it like a selfie shot then you can slide it under or behind you pump or whatever tight area and get a picture of the hard to see area.
check your wiring and lest us know wire colors but if its a two wire 12v pump its hard to wire so it runs backwards cause it will either run if wired correct or wont run at all.
but if it has multiple wires then most of those are for different speeds like high medium or low.
i dont know of any 12v pumps that can be wired different to reverse rotation?
there are many in the 3 phase motor world commercial industrial but never had or heard of a 12v capable.
i second the pump in backward because 1 the pump will only provide minimum flow and barely any pressure difference if the impeller is spinning backwards
2 in most water/heating coil situations the hottest fluid is sent into the bottom of the coil and exits the top of the coil because heat rises so they try to catch as much heat in the airstream before it leaves the coil.
there are alot different scenarios of that idea in my work but i think it doesnt apply in a single row heater coil like you have.
3 i think your pump could be as said before backward and fighting with the water pump on the motor not letting the motor get what it wants.
definitely check pump flow arrow.
trace tubing from engine to pump and verify if the pump is supposed to be pulling from or pushing to radiator? or engine before/after thermostat housing.?
i will have to look up your specific engine before i say anymore about where from and back to because i have a special case car in my driveway right now that blew head gaskets because of cooling issues and the way its piped is one of the craziest i have ever worked?
it even has a power steering fluid cooler not even the size of my hand?
sorry for the extra?
hope this helps with ideas.
they like to hide them on the bottom of the casing where you cant see most of the time.
but is your smart phone isnt stupid sometimes like mine?
turn on your camera reverse it like a selfie shot then you can slide it under or behind you pump or whatever tight area and get a picture of the hard to see area.
check your wiring and lest us know wire colors but if its a two wire 12v pump its hard to wire so it runs backwards cause it will either run if wired correct or wont run at all.
but if it has multiple wires then most of those are for different speeds like high medium or low.
i dont know of any 12v pumps that can be wired different to reverse rotation?
there are many in the 3 phase motor world commercial industrial but never had or heard of a 12v capable.
i second the pump in backward because 1 the pump will only provide minimum flow and barely any pressure difference if the impeller is spinning backwards
2 in most water/heating coil situations the hottest fluid is sent into the bottom of the coil and exits the top of the coil because heat rises so they try to catch as much heat in the airstream before it leaves the coil.
there are alot different scenarios of that idea in my work but i think it doesnt apply in a single row heater coil like you have.
3 i think your pump could be as said before backward and fighting with the water pump on the motor not letting the motor get what it wants.
definitely check pump flow arrow.
trace tubing from engine to pump and verify if the pump is supposed to be pulling from or pushing to radiator? or engine before/after thermostat housing.?
i will have to look up your specific engine before i say anymore about where from and back to because i have a special case car in my driveway right now that blew head gaskets because of cooling issues and the way its piped is one of the craziest i have ever worked?
it even has a power steering fluid cooler not even the size of my hand?
sorry for the extra?
hope this helps with ideas.
Jolly Roger bus 223
Senior Member
sorry there was more from me but i got distracted.
definitely an IR gun to check temps.
dont trust temp sending units or guages especially if the guage is reading directly off the sending unit.
an IR gun on the radiator hoses top and bottom and heater hoses top and bottom without pump on and with pump on.
radiator itself in my mind is not a true reading unless going down the road because of airflow across it? an opinion?
the motor creates its own heat and the block retains heat and heated metal radiates out. so the only true place i might trust an IR gun would be the thermostat housing?
i have found in my experience that the rubber tubing will give you a more accurate temp.
dfeazelle. i know we have talked a few times on here but PM me and i will give you my phone number. only 3-1/2 hours away.
i have mechaniced most my life and my oldest son is a mechanic now and he carries a complete toolbox in his car.
PM me we can schedule something mostly weekend hit and miss on saturday.
definitely an IR gun to check temps.
dont trust temp sending units or guages especially if the guage is reading directly off the sending unit.
an IR gun on the radiator hoses top and bottom and heater hoses top and bottom without pump on and with pump on.
radiator itself in my mind is not a true reading unless going down the road because of airflow across it? an opinion?
the motor creates its own heat and the block retains heat and heated metal radiates out. so the only true place i might trust an IR gun would be the thermostat housing?
i have found in my experience that the rubber tubing will give you a more accurate temp.
dfeazelle. i know we have talked a few times on here but PM me and i will give you my phone number. only 3-1/2 hours away.
i have mechaniced most my life and my oldest son is a mechanic now and he carries a complete toolbox in his car.
PM me we can schedule something mostly weekend hit and miss on saturday.
s2mikon
Senior Member
One of the things you NEED is an ir temperature gun. This takes all the guess work out. Check for wheel bearings while in transit, tire overheating coolant temperature double checking blocked radiators ac systems and covid 19. 
Advanced auto parts, NAPA or home depot. What is the top to bottom temperature differential of your radiator? This will tell you. And as others have said learn DIY. We all are here to help. Most of us have to turn so many hours of community service anyway. So ask, send pictures and don't be discouraged.
Advanced auto parts, NAPA or home depot. What is the top to bottom temperature differential of your radiator? This will tell you. And as others have said learn DIY. We all are here to help. Most of us have to turn so many hours of community service anyway. So ask, send pictures and don't be discouraged.I attempted to send you a message but can't tell if it went through.
Thank you!
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