Did a search and didn't turn up anything. I was browsing through Excelerate's new website and saw that on a few of the radiator caps for sale there were claims about radiator efficiency increases by using them. Something to do with a stiffer spring in the cap creating more pressure and lowering the boiling point of the coolant? School me, I can't imagine that a simple cap would make a drastic difference on your cooling system.

cap makes higher pressure......i read a great article on it once...cant remember where

google it... spoon makes great caps... i think 1.3 instead of 1.1, increased the pressure, which increases the boiling point...something along those lines

I've got a greddy one... 1.3... my friends rock skunk2 one's...

I like the skunk2 one better since it is black and red... if you want the greddy one holla at me...

Increased pressure does in fact Increase the Boiling Point of a liquid up to the liquids "critical point".


Although I've heard of this before (High Pressure Radiator Caps), I don't see the point UNLESS you are reaching coolant temps above (or very near) the coolant boiling point.

As a reference:

Peak Long Life 50/50 = 226* Boiling Point (per MSDS)
Peak Global Life Time 50/50 = 226* Boiling Point (per MSDS)
Prestone 50/50 = 265* "Boil Over Protection"
Prestone Prime 50/50 = 265* "Boil Over Protection"
Valvoline/Zerex Original = 265* Boiling Point at 55% conc.


I *assume* Honda/Acura Coolant is similar: 250* - 275* Boiling Point at recommened dilution.

I have a GReddy 1.3, doesn't do much performance wise, just engine bling

If the temp guage ever reads more than 1/2 in your TL- you have a problem
No cap is going to make the TL cool better
If you had a supercharger then we need to talk!

...i'm listening..

sssshhhh no whiners

no whiners

on that question.. i had a TL and a TL-S... my type-s, that temp gauge NEVER goes over like...1/3.. the TL would go up to about 3/8...

i was doing some reading last night, i never knew the type-s came with an external tranny fluid cooler.. unlike the base TL's... good to know

I think after '07 all TL models came with an external tranny cooler, I guess it took them three years to realize the TL really needed one.

Anybody know what the temps are for the Temp Guage? Also where is the Thermometer located - in a relatively "cool" place or a relatively "hot" one?

Mine guage sits dead center ('07 TL-S) once the car is up to temperature.

Also curious what is the MAX coolant temp anywhere in the cooling system? If the max temp approaches 250*, anywhere in the cooling system, then a high pressure cap *might* be marginally helpful.

My *guess* is that Stock, under "normal" conditions the max temp is well below 250-ish, so no chance the coolant will vaporize. But under extreme conditions, S/C, etc -

dead center?? really? no kidding. mine will NEVER EVER go over 1/3 of the way up.. even when i drive 3 hours straight in the summer... hell, even why i dyno it or floor it...

Is yours an 07 or 08 TL-S? I didn't know they had tranny coolers either..

Yeah. Really. I'll double check and watch it over the week-end - it's going to be HOT! HOT! HOT!, but I am 99.9% sure it's dead center and stays there once it gets warm.

08 TypeS

Yea i didnt know either, i was reading it last night in this article

Sweet, I'm guessing mine comes with one too! Good to know.

My temperature gauge usually stays a few ticks under half on my 07 TL-S.

Forgot to post back. Mine is the same as yours - not dead center. It points dead to the right (3 o'clock position) but after looking closer, that is few ticks under dead center.