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celica9303
12-12-2008, 08:23 PM
i just recently purchaced an authentic TRD s-type radiator cap from a member on alltrac.net. i mainly bought it because it looks alot better than my stock one. but after some research i fould it is suppose to raise the boiling point of the coolant...what is the benifit from this? it does this by increasing the pressure. jusat wondering is there is really any benifit from this

wil post pix later its cold outside.

p.s.
i have been havig an idle issue with my car once, once the idle drops to 700 or so it hunts and some tim drops lower and rises back up and then stays at 700 to 900rpm and repeats ....any help is wonderful. toyota tech said it could be a faulty wts(water temp sensor aka coolant temp?)

vip09
12-12-2008, 08:44 PM
For the hunting idle, you can also clean/check your ISCV/IACV (idle speed/idle air control valve). Not sure on the 5s throttle body, but on my 3s and 2zz it's a little green box.

Corey Darling
12-12-2008, 09:01 PM
The higher boiling point means the coolant can't vaporize under harsh conditions - which might lead to cracked blocks.

wizzards581
12-12-2008, 09:14 PM
looks alot better

:bigthumbu

celica9303
12-12-2008, 09:22 PM
Thanks VIP ill check it out.

Galcobar
12-13-2008, 01:02 AM
All radiator caps act as pressure valves on the system -- which makes it a requirement you have the correct radiator cap for your system, and not just one that fits on the radiator.

By keeping the system under pressure, the coolant cannot boil as easily -- boiling coolant does very little cooling. As the engine produce far more heat than would be required to boil coolant not under pressure, keeping the system under pressure means it can cool the engine even under stress.

The radiator cap maintains the volume of the coolant in the system, which increases as the temperature rises.

celica9303
12-13-2008, 04:08 PM
Im aware of why we need a radiator cap and what it does. But thanks for the explaniation some other member might not know. So by raising the bp wil it allow my engine to run cooler and more efficient? What gains will I get from this upgraded cap?

85gtsblackman
12-13-2008, 05:43 PM
u just answered your own question

T-spoon
12-13-2008, 06:47 PM
Im aware of why we need a radiator cap and what it does. But thanks for the explaniation some other member might not know. So by raising the bp wil it allow my engine to run cooler and more efficient? What gains will I get from this upgraded cap?

Probably all it's going to do for you is find any weak coolant hoses in your system. If there was any practical application for higher pressure on the car from the factory, they'd have just used a higher pressure cap to begin with. The only time I can imagine it being useful is for applications like road racing where your engine is working overtime for long periods.

Kastigir
12-13-2008, 07:57 PM
Or for boosted engines. I don't imagine the pressure of the TRD cap is that much higher that would cause a problem.

T-spoon
12-13-2008, 08:03 PM
Or for boosted engines. I don't imagine the pressure of the TRD cap is that much higher that would cause a problem.

Only boosted engines running under the same more extreme conditions. Factory MR2s and Alltracs for instance have no cooling issues under normal driving conditions unless something is wrong with the system.

However, I didn't say it will CAUSE a problem to make the system higher pressure, just that it could find existing issues sooner. Most of our cars are not young and have crusty old hoses. Just saying... any benefit is so negligable that the small negatives cancel them out. It does look nifty though, and that's an ok reason to use it for many/most people.

Kastigir
12-13-2008, 08:06 PM
I agree.