Radiator Cap, how many pounds?

[MandarinaRacing]

I currently have a 13# radiator cap on my radiator, but I was reading an article on Mustang Monthly and it said:

Radiator caps are pressure rated for various applications. Classic Mustang radiator caps are typically 7-8 pounds. Caps for late-model Mustangs are in the 14-18-pound range because they run at higher temperatures

Is this true????
On my last roadtrip, when I parked the car, I could hear a little hiss coming from the rad, and I'm sure it wasn't the cap, this is a new NOS 3-row...could the wrong cap pressure cause pinhole leaks on a rad???

Alex

 

[CobraSix]

Hope not, I'm running a 13# cap as that is what the guide at Autozone told me to run for my year car and engine. Haven't found any leaks in my radiator.

Slade

 

[LaGrasta]

I'd have to run out and check, but I thought I had a 16# cap. No problems, ever.

Double checked it… 13# cap.

 

[65coupei6]

I believe the "original" cap pressure should be 11 lbs. Most peopple run 13 lbs. You can of course go to a higher 16 lbs. cap which will raise your boiling boint. Also, only switch to a higher pressure cap if your cooling system is in good working order. Meaning new hoses and radiator. If you have an old radiator it might not be able to handle the higher pressure.

Alex, if your radiator original?

 

[Anonymous]

i am running i think 16lbs cap, it is a chrome one i got from summit racing seems to work fine fine

 

[MandarinaRacing]

Alex, if your radiator original?

No it's a 3-core from Auto-Zoo or one of those places...The thing that bugs me is that I've had any overheating problems, but this article kinda shocked me!

Alex

 

[Anonymous]

Mine has a 13 lb cap also.

No worries Alex!

Later,

Doug

 

[65coupei6]

http://www.stewartcomponents.com/Tech_Tips.htm

 

[Anonymous]

I have run a 7 lb cap since I had my original radiator redone. By what I understand, the higher the pressure the shorter the life of the radiator. The lower the pressure the longer the life of the radiator. I have had no overheating problems with the lower pressure cap. It never goes past the half way mark on the temp gauge.

 

[LEROY POLL]

HEY MANDERIN


.....THE RATING IS FOR HIGHER EL. 1000 FT. AND UP. AT SEA LEVEL WATER BOILS AT 212*. SEA LEVEL IS AT ABOUT 14+ LBS OF PRESURE. THIS CHANGES THE HGHER YOU DRIVE. WATER WILL BOIL AT LESS THAN 170* AT 7000 FT.

.....LET US JUST SAY YOU ARE RUNNING A 200* THREMOSTAT AND NO CAP ON THE RADIATOR. YOU DRIVE TO THE MOUNTAINS AT 7000 FT. YOU BOIL ALL THE WATER OUT OF YOUR CAR IN JUST A FEW MINUTES. THE WATER IS BOILLING AT 170* AND YOU GET STEAM BEFORE YOU CAN OPEN YOUR THERMOSTAT. WITH THE CAP ON THE SYSTEM THE WATER SEE 14 LBS AND WILL BOIL AT 212*. IT WILL NEVER BOIL AWAY UNTIL IT REACHES 212*. WATER WILL COOL YOUR MOTOR AS LONG AS IT DOESN'T TURN TO STEAM.

.....THE HIGHER THE PRESURE RATING THE HIGHER THE BOILLING POINT OF WATER IN YOUR SYSTEM. MOST ALL SYSTEMS ARE RATED AT 250* AND ABOUT 20 LBS OF PRESURE.

.....WHEM YOUR MOTOR BECOME A PRESURE COOKER YOU NEED TO HAVE A CAP TO KEEP COOLENT FROM TURNING TO STEAM. AT 195* YOU WILL GET ENOUGH EXPAINTION TO PUSH WATER OUT PASSED THE CAP. SO DON'T REFILL WHEN IT IS COLD.

LIVE IN GRACE

LEROY POLL