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1967 Ford Fairlane
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Discussion Starter · #1 ·
G'day team,

Just wondering if I've got the correct rating of radiator cap on my '67 Fairlane... it says "0.9" which I presume is some sort of kPa unit. Should I have a "1.0" instead?

Surprisingly, I can't find the correct spec. in my workshop manual.

Cheers,
Mike.
 

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Phoenix, AZ 85008
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The spec in the 1970 and 1971 Ford car Shop manual is 12 to 16 PSI for all models both years.
Using the internet for conversion that would be 82 Kilopascal to 110 Kilopascal
Does that make sense?

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Phoenix, AZ 85008
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The original cap from the factory looked like the attached

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Font Circle Nickel Metal Auto part
 
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And the 1964 Ford and Mercury shop manual specifies 12 to 15 PSI (all engines).
Interestingly, the '66 Comet, Falcon, Fairlane and Mustang FSM does not list a nominal spec for radiator caps.
IMHO, if the cap fits and is holding pressure, 13 PSI s/b OK.
Kevin
 

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1967 Ford Fairlane
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Discussion Starter · #5 ·
Thanks guys, that's really helpful. I'm going to take a punt and say that 13psi is about right.

[Sidenote: I'm from Australia, where we converted to metric way back in '66, but for the life of me I have never been able to understand those daft kilopascals (kPa) or whatever they are. Give me PSI every time, please!]

Happily, this corresponds near-as-dammit to the 0.9 Bar marked on the cap. So the current cap will stay.

And thanks Mr. Action for the pic of the original lid. I like the small original touches (my car is a long way from an original pristine example, and is unlikely to ever be so again), so I'll be tracking down an Autolite lid.

Cheers,
Mike.
 

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Phoenix, AZ 85008
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The picture of the cap came from a well known Mustang parts sales website.
I think the price of the cap was over $20 USD plus shipping.

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A higher pressure does not deliver more efficient cooling. (At least I do not think so)
It does allow the system to handle more heat without adverse impact. (Boil over)
And the pressure may speed up the heating process.
Every pound of pressure to the cooling system the boiling point (Over heating) increases by 3 degrees f to the coolant.

If the cap is rated for 14psi, the coolant has a 42 degree f increase in boiling.
On water only the boiling point would be 212f + 42f = 254 degres f at sea level.
One of the goals of the thermostat is to get the coolant mixture temperature up as fast as possible. Then hold the temperature to a certain window as this makes for the most efficent engine operation. The air fuel mixture lites off more completely when the engine is in that temperature range.

Not sure about 1967, much later engines run more efficiently at 205 to 215 degrees f.
My guess is back then a 200 degree f temp was desired.
An anti-freeze and water mixture also increases the boiling point.

I will leave it to you to do the conversions to metric

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1967 Ford Fairlane
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Discussion Starter · #9 ·
A higher pressure does not deliver more efficient cooling. (At least I do not think so)
It does allow the system to handle more heat without adverse impact. (Boil over)
And the pressure may speed up the heating process.
Every pound of pressure to the cooling system the boiling point (Over heating) increases by 3 degrees f to the coolant.

If the cap is rated for 14psi, the coolant has a 42 degree f increase in boiling.
On water only the boiling point would be 212f + 42f = 254 degres f at sea level.
One of the goals of the thermostat is to get the coolant mixture temperature up as fast as possible. Then hold the temperature to a certain window as this makes for the most efficent engine operation. The air fuel mixture lites off more completely when the engine is in that temperature range.

Not sure about 1967, much later engines run more efficiently at 205 to 215 degrees f.
My guess is back then a 200 degree f temp was desired.
An anti-freeze and water mixture also increases the boiling point.

I will leave it to you to do the conversions to metric

Action
Thanks Action, appreciate the prompt and detailed reply (y) just what I needed. Something to learn every time we face a challenge with these old beasts, eh.
 
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