Hello all,

This is my first time posting here so excuse me if i am in the wrong place, but i just recently swapped out my OEM radiator to an aftermarket one in my 1982 GSL. The aftermarket radiator did not have spots to put my coolant level sensor or my temperature sensor. Could anyone give me some suggestions? I just dont know where the best place to install these would be. Thanks in advanced

 

They need to go where the factory ones are. The car will run without them. You won't have a low coolant level. Not sure what that temp sensor does.

 

Since you have nowhere to put them just ground the coolant level wire to the panel in front of the rad and you won't have any lights on the dash. Just check the coolant level regularly. Your temperature sensor will not be on the rad.

 

Yeah I never bother running the low coolant sensor (the one that goes on the top of the radiator - as said above, ground the wire so it doesn't constantly ding). I believe the sensor at the bottom of the radiator is used to trigger the cold start fluid, which no one has used in decades on these cars, so it can go in the trash too

The coolant temp sensor to turn off the choke is on the water pump housing, so that won't be affected, and the gauge sender is on the rear iron, again, not affected by a radiator swap.

 

As 82TA just wrote, the lower left coolant sensor only effects/controls the sub-zero start system, which is useless trash anyway ( I believe Mazda had a service bulletin back in the day to disconnect that system).
The coolant level sensor (top center on OE radiator) triggers an idiot light on the guage cluster but I dont think it affects operation.
What radiator do you have? I got a new Koyorad from Mazdatrix about 6 months ago and it has the level-sensor bung.

 

I installed a ebay radiator....pretty nice but I can't use the coolant level sensor because the thread diameter it's smaller than the bung on the radiator....so I will not be using it......

I will try to find an aluminum cap to screw in its place and take out the plastic thingy there on top....

 

I was wrong when I wrote this. The sensor that controls the sub-zero is actually in the oil pan next to the oil-level-float sensor. The coolant sensor in the lower left of radiator controls subtle aspects of the emissions system by affecting one of the solenoids in the rats nest, and apparently fast idle & fuel ratio during cold starts on early EFI cars (GSL-SE & S4's). I actually knew this because I have been on several threads about this lately, but I'm having mental clarity issues lately (80 hour work-weeks can do that to ya).

 

^ Ah yes, I forgot about the second sensor in the oil pan. It's been maaaany years since I worked on anything 12a related

 

So the lower left sensor can be deleted if rats nest is gone?

 

That is my understanding. There are 2 threads going on at the same time about this same question (about the purpose of that lower-left radiator sensor). Apparently on a 12A car, if you don't have the rat's nests anymore, then it doesn't serve a purpose anymore. I think if you have an early EFI car like a GSL-SE or an 86-88 FC (s4) then it controls the cold-start idle speed and fuel curve.

Look at the current thread "Put a new radiator in, have a sensor left out" in the New Member RX-7 Tech section. mR.dna explains the actual factory working of that sensor better than I can.