The pressure cap on my s4 water neck is not holding to the pressure. I found that Mazdatrix sells the cap and neck together but I don't need both. So where can I buy just the cap itself?

One thing I don't understand about the system is why it has 2 pressure release caps. I wouldn't see any harm in the upper cap being solid and not releasing pressure since the radiator cap does.

Are there any other vehicle caps that will fit?

Thanks for the help.

 

http://mazdatrix.com/getprice.asp?partnum=15-2050-D316

 

whatever you do. use mazda OE cap only. stant and others have been known to cause issues.

 

i run the flat cap one off the t-stat and the pressure on the rad.

http://mazdatrix.com/getprice.asp?partnum=15-2050-KF01

 

Ray Crowe
Got mine there and other oem stuff.

 

what kind of issues?

 

dunno, i have never used anything but the OE cap., i have jus heard that many have had probs. but heres an equally undescriptive thread about it:

https://www.rx7club.com/showthread.p...t=radiator+cap

no real reasons given

 

so that flat cap does not have any pressure release and can be used safely on the thermo neck?

 

i think i just figured out why my coolant is leaking from under the intake as of the day i bought a stant cap time to order a mazda cap and tear stuff apart


just ordered a mazda flat cap and a new thermostat housing gasket because i have a small leak there too.

after school project this week pull the intake, find the leak, fix it, and have it back together and have my new struts on by friday at 4:30

 

yea that is how it should be from the factory you dont need/want 2 pressure caps.

 

2 pressure caps cause big problems due to small plastic hoses so now i have to pull my intake

 

What? I don't exactly understand what your saying.

I am going to try another radiator cap I have because I noticed the seal is broken on the one I have on the thermohousing.

 

Mazdatrix sells both.

 

Several times I have had to use a pressure cap on the T housing...as I could not find a flat cap...I always used a pressure cap that is rated higher than the Radiator cap...never had a problem, BUT....that pesky O RING on the T Housing leaks very easy and good luck in finding one that is the proper size...Mazda dealer don't even have em !

 

i had a pressure cap on the t-stat housing and it caused a small hose to burs under my intake manifold/intake runners/throttle body area

 

I don't see how a pressure cap can cause a hose to burst under the intake manifold.

I threw a stant radiator cap on there to see if it seals. I don't really see how it wont leak out the top because of the stud but we will see.

 

when I had to change that part I just always bought the entire assembly, my thinking was they sell it as a pair for a good reason im sure, it comes with everything you need for install, just buy the pair.

 

well i replaced the the hose today and its more of a pain in the a$$ to scrape off the old the intake gasket than anything but i replaced all the hoses under the intake just waiting for a new gasket and the new flat cap and t-stat housing gasket should all be here by friday and back together and my struts on

 

most of the used fc i deal with all have 2 pressure's on there and it works but i think it works better with the 1 flat and the 1 pressure

 

I run TWO..no problems..but the flat cap is only used on a thermostat housing without the nipple for overflow.

 

yea it definetly doesnt have a nipple

 

Stant unit is holding up well, its really cold outside so hard to get the water temps up to truly test it out but after long drive with lots of acceleration not a drip.