I just installed a 1983 radiator I got from a nearby wrecker. Everything is identical to my old radiator except that the neck on the top tank for the pressure cap is smaller than the original one. The original was about 1 3/4" diameter but the newer one is 1 1/4" diameter. Unfortunately there is no listing at my supplier for the smaller cap. Anyone know what type or size the smaller pressure cap is?

 

check mazdatrix for part #'s, they are just listed backwards. NAPA should have the part # for that none the less.

 

mazda does not offer a different cap for different pressures. the cooling system is designed to run at a specific pressure and only that pressure. the only cap thats different is the cap for the 84-85 GSL-SE. it actually has wider mounting ears on the cap itself.

 

I ran into this same issue with a replacement rad. The smaller cap you want is the same as the cap for the 2nd gen rx-7. Stant part number 10327

 

Sgt Fox, thanks for the info. It is most helpful.

 

Let me know if it works. I was just going off what I had to use on my aftermarket rad. Your may still be different yet.

 

A 1986 RX7 rad cap worked perfectly. Thanks again.