I think my radiator cap at the filler neck (end of the hose that goes towards the engine block) may be messed up. I'm slowly oozing coolant out of the sides of the cap. At first I thought it was the piece where the cap screws down onto, but I took it apart and the gasket is fine, so are the bolts (they are new). So for about a week now I've been driving it and after the drive, open the hood and check it out, and it is indeed coming from the top of the cap. Do I just need a new cap or could it be a bigger problem? There are no leaks on the ground, just a little bit of coolant loss every day.

 

First of all, is it a normal rad cap, or a flat cap that you have at the filler neck? Should be a flat cap (but rad caps will work). They are not much at all, maybe $15. So, IF the housing mating surfaces for the cap/gasket are not bent, dented, etc, a new cap should do the trick...

 

Hey I seem to be having exactly the same problem. I took off the sticker off the top of my cap and noticed a disc underneath. Coolant was come out from the edges of this disc. I replaced it with my Fluidyne cap allthough this holds slightly higher pressure (16lbs vs 13 lbs on the stocker)

 

We had this problem with out track car a few weeks ago.
The cheapie rad cap from Checkers was JUNK.
The metal was soft, and this allowed the cap to flare under pressure.
I crimped it twice, and it kept flexing.
So there are crappy quality caps being sold.
We replaced it with a Nissan (go figure) rad cap, and it was noticable thicker (stainless) steel.


-Ted

 

Hmm, thanks guys, I'm going to go pick up a new cap tomorrow and maybe apply some gasket to the housing mating surface like you said. Thanks a lot!

 

Well I'm still searching for a cap, but I have not found any replacements aside from the OEM ones Mazdatrix has. Does anyone know if the FD radiator caps will work on our FC? If so I can just pick up one of the 1.2/1.3 bar caps on the rx7store. Or you think an OEM cap from Mazdatrix will fix my problem just fine?

 

OEM and why not from the local MAzda dealer?

 

Yes, FD cap works, but I think you can't get the cap by itself?
Last time I ordered one, it came with the filler flange.


-Ted

 

"First of all, is it a normal rad cap, or a flat cap that you have at the filler neck? Should be a flat cap (but rad caps will work). They are not much at all, maybe $15. So, IF the housing mating surfaces for the cap/gasket are not bent, dented, etc, a new cap should do the trick..."

This confuses me a bit. Do you mean in the center of the cap, is it all flat or is there a circular crevice? Mine at the filler neck has the crevice in the center, its the pressure type I'm pretty sure as it has a spring and gaskets under it, and it says 13lbs. Is that the correct one that goes at the filler neck? If so I'm going to pick one up off Mazdatrix... but if you guys could let me know if I'm picking the right one, I'd appreciate it. I think its the one marked 'G'....



Radiator Caps & Cap Assembly
Image Year/Model Part Number
(E) 79-85 (except GSLSE) 15-2050-8871
(F) GSLSE (and all thru 78) 15-2050-SE01
(G) 86-95 (Pressure cap) 15-2050-D316
(H) 86-92 & 93-95 Flat Cap 15-2050-KF01
(J) 86 Cap Assembly w/overflow tube 15-17YA-N326
(K) 87-88 Cap Assembly w/o overflow tube 15-17Y0-N323
O-ring for (J) & (K) above 15-1740-N326

 

The "H" is the flat cap, but as I said, a regular springy-thingy rad cap will work (I have one on my filler neck for a back-up to the radiator cap, should it ever hang up on me). If you are ordering from Mazdatrix, let them know that you are a confused lad & those guys will hook you up, they're talented fellows when it comes to rx-7's...

 

I think I finally found the problem, heh. upon closer inspection just now, this is what I saw:




I cant believe I didn't notice the crack there before... I must have been too focused on the green coolant oozing out around it and the top (which you can see in the second pic). That's what I get for overtightening the bolts. So now I guess my only choice is getting a new radiator cap plus the bottom assembly, and the O-ring gasket that goes underneath, which would be part labeled "K" in the picture below:


Anyone have any input, comments? I'm gonna put some gasket-in-a-tube between the cap and assembly also, shouldn't hurt. I hope I'm right about all this!

 

You can use RTV if you wish, but if you're using a new assy with a new o-ring, you shouldn't need to...

We can only help those who help themselves- please find your cracks BEFORE leading us down the path of radiator caps 101 next time, lol...