Radiator cap question

[mooch91]

I've seen a few posts suggesting a 0.9 bar radiator cap is required for the 3rd gen trucks and not a 1.1 bar cap.

My 2002 SR5 Sport has a 1.1 bar cap and Stant shows a 16 psi (1.1 bar) cap as a replacement.

Anyone know the origin of the 0.9 bar requirement? I've seen it pointed out in a few posts on this forum, just no explanation.

What pressure does everyone's cap say?

Thanks!

 

[TheDurk]

The FSM says:

Standard opening pressure:
74-103 kPa (0.75-1.05 kgf/cm2, 10.7 - 14.9 psi)
Minimum opening pressure:
59 kPa (0.6 kgf/cm2, 8.5 psi)

 

[tenro1]

sorry for being dumb here, just woke up, but - can you translate this into what bar it represents? I just replaced mine as well about 2 weeks ago, and while I am not sure at the moment what I have on the rad, if it is the wrong one I would like to know. Thanks!

The FSM says:

Standard opening pressure:
74-103 kPa (0.75-1.05 kgf/cm2, 10.7 - 14.9 psi)
Minimum opening pressure:
59 kPa (0.6 kgf/cm2, 8.5 psi)

 

[mooch91]

sorry for being dumb here, just woke up, but - can you translate this into what bar it represents? I just replaced mine as well about 2 weeks ago, and while I am not sure at the moment what I have on the rad, if it is the wrong one I would like to know. Thanks!



Standard opening pressure:
74-103 kPa (0.75-1.05 kgf/cm2, 10.7 - 14.9 psi)
Minimum opening pressure:
59 kPa (0.6 kgf/cm2, 8.5 psi)

Standard opening pressure:
0.74-1.03 bar
Minimum opening pressure:
0.59 bar

Perhaps the 1.1 I have on my truck was replaced at some point? Anyone have the original on their truck and know what pressure it's rated at (should be stamped on one of the wings)?

 

[TheDurk]

sorry for being dumb here, just woke up, but - can you translate this into what bar it represents? I just replaced mine as well about 2 weeks ago, and while I am not sure at the moment what I have on the rad, if it is the wrong one I would like to know. Thanks!



Standard opening pressure:
74-103 kPa (0.75-1.05 kgf/cm2, 10.7 - 14.9 psi)
Minimum opening pressure:
59 kPa (0.6 kgf/cm2, 8.5 psi)

1 bar = 100kPa = 14.5 psi

....so a .9 bar looks about right for that range.

 

[LittleCaesar]

The radiator cap changed between the years 2000 and 2001 (going from a .9bar to 1.1).

Why? Do not know.

 

[TheDurk]

The radiator cap changed between the years 2000 and 2001 (going from a .9bar to 1.1).

Why? Do not know.

Interesting. That .74 - 1.03 bar cap test spec I posted is from the 2002 FSM. I just checked my paper '99 FSM and it has the exact same thing.

BUT:

My '99 calls for a rad cap # 16401-72090, which is listed as good for 1995.11-2000.08, or MY's '95-'00.This is 0.9 bar:

Later 4Runners get the 16401-62100. This last is definitely 1.1 bar:

So [MENTION=69868]LittleCaesar[/MENTION] speaketh the truth, even though the 1.1 bar would not meet the FSM test spec for 2002. Strange...

 

[LittleCaesar]

When I went to the dealer years ago to get replacement OEM parts, I would usually tell just them they were for a 3rd gen runner, but the parts guy told me he needed my year (99) to get the correct radiator cap.

In my experience Toyota and others makers, when they use different parts in later years of the same production of a car or truck, usually just use the latest part to cover all applications (ex: the 96-98s 4runners used different crank bolts than in later years but are all speced for the same one now). Not for the radiator cap though. The parts guy did not know why either. Not for me to second guess the reasoning why.

 

[02SE]

Raising the radiator cap opening pressure, raises the pressure in the cooling system. That in turn raises the temperature the coolant can reach before it boils. Raising the cooling system pressure too much, can create problems too. So it's a fine line.

Basically a slightly higher PSI Radiator Cap, is a little extra insurance against boil-over.

Rather than typing out a long-winded post, I found an article that describes this well.

Beating the Heat: Advantage of a High Pressure Radiator Cap | Tuner University

 

[tenro1]

Very informative stuff....

So - at the end of the day, on my 2001 runner, 1.1 bar is the correct application, based on TheDurk's latest research?

Thanks,
Michael

 

[mooch91]

I guess I'm going to go with the 1.1 as a replacement on my 2002 based on the info above!

Follow-on question: OEM or Stant?

 

[UTEP]

I'm in the same boat fixin for a trip and can't get to Toyota. Is a Stant a worthy substitute ? I passed on a cheap looking napa made in China thing.

Thanks

 

[mooch91]

I'm in the same boat fixin for a trip and can't get to Toyota. Is a Stant a worthy substitute ? I passed on a cheap looking napa made in China thing.

Thanks

I went with the Stant. It's made in China. But so far, so good, after one day. It was only $9 - if it goes bad, I can buy the Toyota one then.

 

[cyclops13]

My coolant temp shows around 203 on the Torque lite app connected to the OBD2 dongle. While its not high really but was wondering should I replace the radiator cap as a preventive maintenance? I did replace the radiator sometime back but never really replaced the cap.

Also, is this a good replacement cap for a 97 SR5 Auto?

ToughOne Radiator Cap 10241: Get a new radiator cap at Advance Auto Parts