This might be a dumb question, but I'm gonna shoot. My RX7 (S4 NA) has had cooling system issues since day 1. Not too long ago the water pump gasket and the housing to block gasket blew out. After replacing those and some blue RTV, after driving the car for a while the o-ring underneath the coolant filler/pressure cap blew out, along with a small leak around the thermostat housing gasket. I did a little bit of perusing and found that the plastic piece the pressure cap screws onto is supposed to have a nipple that connects to the overflow tank. The piece currently on the car doesn't have this nipple, so the overflow tank isn't connected at all. Could this be the reason for my gaskets constantly blowing out because the pressure has nowhere to vent to? Car has never overheated. Can post pictures later tonight when I get home from school if need be.

 

yes, if the pressure can't vent like it is supposed too, then it will go somewhere.

b, the blue stuff is a really old formula, and you would be much better off with the newer stuff.

 

What would you recommend instead of blue gasket goo? Thanks for confirming my idea, some previous mechanic must've been a dumbass...

 

I think he's referring to the Permatex Ultra Grey or Ultra Black. I've used both with success on My Toyota truck I had. They used gasket maker in place of an actual gasket in quiet a few places. As of late I've been using the ultra black if I'm sealing oil and the ultra grey for just about everything else.

 

What radiator cap do you have?
Some after market ones are rated with a higher pressure than stock.
Do you have your over flow tank still installed and does it get cycled in and out the cooling system?

 

there are like 3-4 different configurations for the cooling system, and its possible to mix stuff up and not have a radiator cap and stuff like that

in permatex, they have the "right stuff" which is ok, the factory used Takata SH780M, and the current Mazda stuff is a Three Bond TB1217D

 

Corksport (16 psi so a little over stock). I found the line that would've gone to that vent nipple, not connected to anything. So the tank is in the car it's just not hooked up to anything.

 

just put it back to stock configuration. put a stock radiator cap on there and get the vent working. there's no need for a 16psi radiator cap.