Radiator cap .9 or 1.1?

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Pmo75
Posts: 23
Joined: Sat Nov 17, 2018 2:22 pm

Radiator cap .9 or 1.1?

Post by Pmo75 »

Hello all,
I realized while cleaning my engine that my car runs with a 1.1 cap. It’s probably been the case for many many years. .9 is the factory spec.

What are the views on this?

Best

Pierre
1966 330 GT #8941
1968 300 SEL 6.3
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tyang
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Location: New York
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Re: Radiator cap .9 or 1.1?

Post by tyang »

Hi Pierre,

A higher pressure cap increases the boiling point of your coolant, and it also puts more pressure on the system, so it can cause leaks. You can go back to stock or leave it alone if you haven't had any problems.

Tom
'63 330 America #5053
DWR46
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Re: Radiator cap .9 or 1.1?

Post by DWR46 »

Pierre: What model Ferrari do you have? Different models used different pressure caps.
Pmo75
Posts: 23
Joined: Sat Nov 17, 2018 2:22 pm

Re: Radiator cap .9 or 1.1?

Post by Pmo75 »

I have a séries 2 330 GT.
I have to admit I never checked the radiator cap…
Then I need to clean it up and it occurred to me it’s been with this cap for a long time!
1966 330 GT #8941
1968 300 SEL 6.3
DWR46
Posts: 621
Joined: Tue Sep 22, 2009 8:23 pm

Re: Radiator cap .9 or 1.1?

Post by DWR46 »

Correct cap for your car is .9 bar (13 psi). The Italian caps are available from a number of sources.
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tyang
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Re: Radiator cap .9 or 1.1?

Post by tyang »

Pmo75 wrote: Fri Jan 07, 2022 8:22 pm I have a séries 2 330 GT.
I have to admit I never checked the radiator cap…
Then I need to clean it up and it occurred to me it’s been with this cap for a long time!
Not to point out the obvious, but there may be people who don't know, on SII 330s, the cap on the radiator is a simple rubber gasket, while the spring loaded pressure cap is installed on the expansion tank down in the front of the car in front of the radiator. The hose that goes between the radiator and the expansion tank is pressurized. Earlier SI 330s have the pressure cap installed on the radiator and the over flow tube drains to the ground like the 250s.

You can run the car with the pressure cap at the radiator on the SII cars, but it will not work as it was designed with the expansion tank.

Tom
'63 330 America #5053
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