umm, hes talking about radiator caps not turbos. By adding 16 pounds of pressure to the system you will raise the boiling point … … A slowly failing, worn out or faulty radiator cap can result in overheating, loss of coolant or even major engine damage. And yes you should be running a 16psi/lb cap. I have a buddy who's car would over heat in the texas weather. But because a radiator cap maintains pressure in the system, the boiling point is raised and the system is capped off. A high-pressure radiator cap is used to raise the boiling point. Allstar Radiator Cap Small Stant 16 PSI ALL30124. cap gives at least a 250 F boiling point. The radiator cap maintains system pressure to 16 pounds per square inch (psi) on most vehicles. Allstar Radiator Cap 22-24 PSI ALL30136. GM has changed the part number for the radiator surge tank cap on vehicles that came from the factory with Dex-Cool. It is designed to add pressure to the cooling system and increase the boiling point. This is because for every pound of spring pressure, the boiling point is increased by 3° F. Water boils at 212° F, increasing the pressure in a closed system increases the boiling point. ... raising the pressure at which your radiator cap releases is raising the boiling point of the fluid in your cooling system. I've no idea what is listed for SBF. 7 lb cap will work just fine. High-performance caps range from 19 – 32 psi. Boiling point is rated at 133°C/271°F for Expert, and 136°C / 277°F for Factory Line, but only with a +1.5 bar (22 PSI) pressure cap! I believe for a 383 2 barrel a 16 lb is the standard. x 3/4" deep necks unless otherwise noted. Radiator caps hold pressures between 6-16 PSI for most automotive systems. Stant 10231 Radiator Cap - 16 PSI Vented. The caps pressure rating varies by engine application anywhere from 13 – 16 psi. Compare that with typical coolant boiling points in my graph on post # 5 (138°C with 50/50 mixture). will increase the boiling point in a system by 39° F. High-performance caps range from 19 – 32 psi. ACDelco RC85 GM Original Equipment 15 P.S.I. It is designed to add pressure to the cooling system and increase the boiling point like grandma's pressure cooker. Otherwise I can't see any real reason they didn't use a more standard 15 psi cap. Radiator Cap. I'm looking for a new radiator cap so as usual I go to look at Rockauto. This Stant 10231 Radiator cap 16 PSI with a Vented in case of over presser. My current radiator cap is a 13 psi cap and im looking at replacements that are either a 16 or 18 psi. So you should be good to around 240 degrees depending on coolant boiling point. Radiator Caps are manufactured using either metal or plastic design depending on the vehicle manufacturer’s specifications. In all actuality, the formula is: for every 2 PSI increase (at sea level) you increase the boiling point 1* above 212*. Recovery system caps allow coolant to exit the cooling system into an overflow or recovery bottle as coolant heats and expands. The radiator cap actually increases the boiling point of the coolant by about 45 F. Functions of Radiator Pressure Caps. 50/50 mix with a 16 lb. For every pound of pressure in a closed cooling system you raise the boiling point by three degrees. Stant 10227 Radiator Cap - 13 PSI. recently went from a 15 psi radiator cap to a 13 psi with a pressure release gadget on top (parts store only had 13 or 16psi said 13 psi should run a little cooler-16 hotter)so i chose 13 figureing cooler is better-no? You could use a 15 or 16 lb cap, all cooling system components should be tested to say 30 psi. If your gaskets, hoses, radiator are in great shape, that pressure should keep it from puking out coolant when shut down hot. And the boiling point increases 2-3 degrees for each additional psi of pressure in the system. So the over-simplified answer to the tech quiz is that, yes, a higher pressure radiator cap can help prevent overheating. Radiator Caps are designed to seal the top of the radiator filler neck to prevent coolant loss, pressurise the cooling system and raise the boiling point of the coolant. The new cap is 18 PSI (RC87 - part number 25713160), the old one for many vehicles was 15 PSI (RC75 - part number 10296465). So, pressurized cooling systems help prevent overheating and coolant loss. The cap has a small disc at the bottom of the cap that is a vacuum valve. Or does it really make a difference? Higher pressure caps can boost the boiling point even more. The system is pressurized to increase the boiling point of the coolant, by doing so you allow the engine to run hotter without boiling off the coolant thru the overflow. Sunday at NHMS we epoxied the radiator back together, put a 16 lb cap on it, and ran cool all day long. The manufacturer told us that 20 psi would be no problem...it appears they were wrong. The sudden decrease in pressure causes the boiling point to suddenly drop down, so that the entire contents of the radiator is suddenly boiling and spraying out all up in your face and all over everything else. Water boils at 212° F, increasing the pressure in a closed system increases the boiling point. A radiator cap keeps the cooling system pressured which raises the boiling point. The radiator cap is often overlooked in common engine overheating problems. ... all the 16 pound cap does is raise the boiling point of the water. Stant 10231 Radiator Cap - 16 PSI Vented. However, straight water has a lower boiling point than a mixture. That vacuum valve hangs down in the open position until the cap is subjected to rapid expansion of coolant or steam, which closes the valve in a sealed position. FENIX: CAP1021.Upgrade your cooling setup with a Fenix performance radiator cap.Rated to 1.1 Bar / 16 PSI, this radiator cap will raise the coolant pressure and subsequently its boiling point - increasing your cooling system's heat capacity and performance. By increasing the pressure in the cooling system, the boiling point of the coolant is increased to 245 degrees Fahrenheit at 8 PSI. It is designed to add pressure to the cooling system and increase the boiling point like grandma's pressure cooker. x 3/4" deep necks unless otherwise noted. The radiator cap controls this expansion and provides constant pressure on the system. If the pressure on the system drops because of a failing radiator cap, the boiling point … At sea level, water boils at 212 degrees. This means that a cap rated at 13 lbs. One function of the radiator cap is to keep pressure on the cooling system. higher (3 psi times 15 psi cap). ... Hi Luigi, 16 psi is 16lbs, the PSI is "Pounds per square inch" Hence a 16lb cap. The cooling system uses pressure to further raise the boiling point of the coolant. This protects the system from boiling over at the top of the operating temperature range. Whereas water boils at around 212°F. Coolant that is boiling cannot transfer as much heat and overheating is likely to occur. Every PSI increases boiling point 3 degrees. This allows the coolant to reach much higher temperatures without boiling away. With the 1.3 the higher pressure is going to circulate coolant coolant faster, so it will cool the motor better at higher speeds. High-performance engines also create more heat. Ideally, car cooling systems should maintain a pressure of around 13 to 16 PSI. Each lb. Standard size caps fit 2-1/8" O.D. Higher pressures are used to increase the boiling point of the coolant under arduous conditions i.e. Traditionally radiator cap pressures are generally in the 6 to 15 psi range. Also, they raise the coolants boiling point, about 3-degrees F for each additional (psi) above atmospheric pressure. Cooling system pressures are controlled by the radiator cap. racing or desert conditions. or NO…any comment on the difference between mfgrs 15 … I live at 6150' and a 13 psi cap boils at 250 for me. at atmospheric pressure, if exposed to 15 psi (a common radiator pressure cap), the boiling point will now be 45°F. Higher cooling system pressure raises the boiling point of coolant to reduce the risk of overheating. A faulty radiator cap can result in engine overheating, loss of coolant or major engine damage. At higher elevations the boiling temperatures are all lower since atmospheric pressure is lower up here. At that point, the system is pressurized and helps control overheating and enhances system efficiency. How does an increase in pressure affect the coolant is boiling point? Which one do i need? I always knew opening a hot radiator cap was a bad idea, but I guess I never thought about it much in these scientific terms before. A 20 lb cap will bring the boiling temperature of your coolant (water) to about 255 degrees. A faulty radiator cap can cause your car to boil-over at a lower temperature, but is an easy and inexpensive DIY repair. That same mix at 16 pounds per square inch (psi) of pressure boils at approximately 250 degrees. I'd suggest running a normal overflow recovery cap and tank and make sure the radiator is full when up to operating temp, fill the overflow tank to about 1/3 with coolant and call 'er good. of pressure raises the boiling point about 2 degrees, over 2 at 212 and a little less per lb. A faulty radiator cap can cause your car to boil-over at a lower temperature, but is an easy and inexpensive D-I-Y repair. A faulty radiator cap can cause your car to boil-over at a lower temperature, but is an easy and inexpensive D-I … For every pound of pressure exerted on the coolant in the system, the static boiling point of the coolant is increased by 3 degrees F. Keeping coolant in a liquid form allows the fluid to do it's job transferring heat to the radiator to be dissipated. Ford might have been afraid that 16 psi would burst the heater core or maybe the radiator(?). Below are functions of radiator caps in automotive engines: A radiator pressure cap keeps the system pressure at 16 PSI, which avoids the coolant from boiling off even when it gets hotter considerably. Standard size caps fit 2-1/8" O.D. A radiator cap is the part of a vehicle responsible for containing engine coolant and ensuring that the cooling system remains under pressure. Higher cooling system pressure raises the boiling point of coolant to reduce the risk of overheating. But anyways, you should be fine with either the .9 or the 1.3 cap. The radiator cap ensures that this pressure remains constant. I don't remember ever seeing a 16 pound radiator cap before (really high PSI in my mind), I was thinking 8-10 would be more appropriate. To understand why the cooling system is pressurized, consider that for every 1 psi over atmospheric pressure, a liquid’s boiling point is raised 3°F. as the pressure and temp rise.