I'm in need of a radiator and I've got one on my parts car, but it's an early 86 one. There isn't a filler cap on there, and on the sensor in the middle there is a tube coming out of it. Can it be used or should I get another one?

 

yes you can use this radiator and you should be ok even if its an automatic transmission radiator. dont be too concerned about it not having a filler cap since all series 4 rx7's came with an additional filler neck which is situated in the thermostat housing neck, as for the tube comming out from the sensor if you dont need it simply plug it. just make sure you plug it right.

 

So plug that tube coming from the top and I'm good to go? What about replacing that sensor with one from a later year S4?

Thanks for the help.

 

im pretty sure both sensors are compatible however im not 100% sure. check the part number for that sensor and if it matches on both series 4 and 5 then you should be ok

 

i dont think u will be able to fill the rad up. because even when using the filler neck on the water pump it will run out because the motor will fill up before the rad. u would ahve to cycle it alot and run the motor then add more then run the motor and add more.

 

Water finds it's own level. So "filling the motor" is filling the radiator. Besides if the motor is cold the t-stat will stay closed and the water/coolant will go through the upper hose into the radiator then fill the motor. Still have to bleed the system but that doesn't mater where you fill it.

 

you could always take out the level sensor inthe top of the radiator to bleed out the air

 

Use the radiator's overflow nipple to the overflow bottle. Don't use the t-stat housings nipple. Replace that plastic piece with one that has the nipple eliminated...

It was an inferior design....which is why Mazda switched back to one overflow nipple situated on the radiator.