Radiator Cap for HB - Toyota Yaris Forums

paultyler_82 · 12-14-2006, 11:59 PM

"Performance" Radiator caps actually do put the radiator under a higher pressure, allowing for the coolant to do it's job more efficiently and allow the engine to run a bit cooler, depending on other mods, this can make a difference, but only if you're trying to squeeze as much as you possibly can out, and they're what... like 20-30 bucks?

Now for the original question, the TRD Japan part number for the radiator cap that fits the Vitz is P/N:16401-SP030 which is the same as the TRD US part number that you listed second, this is the one that most Toyotas and Lexuses use, the part number for the one you have is TRD JP P/N: 16401-SP002 which is used in some V6 and V8 Toyotas and Lexuses, you need the 18.5psi cap.

Beau · 12-23-2006, 12:12 AM

Quote:

Originally Posted by paultyler_82

"Performance" Radiator caps actually do put the radiator under a higher pressure, allowing for the coolant to do it's job more efficiently and allow the engine to run a bit cooler, depending on other mods, this can make a difference, but only if you're trying to squeeze as much as you possibly can out, and they're what... like 20-30 bucks?

Now for the original question, the TRD Japan part number for the radiator cap that fits the Vitz is P/N:16401-SP030 which is the same as the TRD US part number that you listed second, this is the one that most Toyotas and Lexuses use, the part number for the one you have is TRD JP P/N: 16401-SP002 which is used in some V6 and V8 Toyotas and Lexuses, you need the 18.5psi cap.

Thanks, I had my TRD radiator cap from my old Lexus GS300 and was wondering if it would work....now I know...

Quote:

Originally Posted by paultyler_82

the point of the cap... and the TRD, GReddy, Tom's, and generic all do the same thing, is a higher pressure than the stock cap, that's why I always buy the 5 dollar generic at the local ricer shop, same 18.5psi rating as the 30 dollar TRD cap. I don't buy mine for looks, I buy mine for the increased coolant pressure.

Any examples of the $5 generic and what store to look for it in? Pepboys? etc...?

PetersRedYaris · 12-23-2006, 01:56 AM

It's a terrible mod if you ask me and has no performance value. Higher pressure radiator caps DO NOT lower your coolant temperatures. It's just the opposite in fact; they prevent the coolant from boiling at higher temps. Chemically speaking it's called boiling point elevation. More pressure=higher boiling point. Allowing more pressure to build up can in no way lower the temp of your engine. At most all they can do is prevent your car from boiling over under extremly hard driving. It is however a great way to pop off those spring-like radiator hose clamps, or worse yet blow a radiator hose.

12-14-2006, 11:59 PM	#1
paultyler_82 View User's Garage Drives: 07 Meteorite Metallic Yaris LB Join Date: Jul 2006 Location: USA Posts: 441	"Performance" Radiator caps actually do put the radiator under a higher pressure, allowing for the coolant to do it's job more efficiently and allow the engine to run a bit cooler, depending on other mods, this can make a difference, but only if you're trying to squeeze as much as you possibly can out, and they're what... like 20-30 bucks? Now for the original question, the TRD Japan part number for the radiator cap that fits the Vitz is P/N:16401-SP030 which is the same as the TRD US part number that you listed second, this is the one that most Toyotas and Lexuses use, the part number for the one you have is TRD JP P/N: 16401-SP002 which is used in some V6 and V8 Toyotas and Lexuses, you need the 18.5psi cap.

12-23-2006, 01:56 AM	#3
PetersRedYaris View User's Garage Drives: 2005 Scion xB Join Date: Nov 2006 Location: The Black Hills of South Dakota Posts: 1,059	It's a terrible mod if you ask me and has no performance value. Higher pressure radiator caps DO NOT lower your coolant temperatures. It's just the opposite in fact; they prevent the coolant from boiling at higher temps. Chemically speaking it's called boiling point elevation. More pressure=higher boiling point. Allowing more pressure to build up can in no way lower the temp of your engine. At most all they can do is prevent your car from boiling over under extremly hard driving. It is however a great way to pop off those spring-like radiator hose clamps, or worse yet blow a radiator hose.