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Radiator Cap


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#1 rtorana1

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Posted 05 June 2020 - 08:05 PM

What PSI should the radiator cap be for a HQ 308 be?



#2 Liz Clare

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Posted 05 June 2020 - 08:11 PM

My 308 hatch radiator is 15psi so I’m assuming they would be the same.

Happy to be corrected though.

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Liz :)


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#3 arrimar

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Posted 05 June 2020 - 08:17 PM

Is it 13psi for recovery system and 15psi without?

#4 hanra

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Posted 05 June 2020 - 08:55 PM

I thought it was the other way around ?

#5 Dr Terry

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Posted 06 June 2020 - 08:45 AM

When the HQ was around there were no recovery systems. Also there should be no difference in the cap's psi recovery or not.

 

All engines from the 173 to the 308 V8 had 13 psi caps as standard from the factory.

 

This was increased to 15 psi for factory A/C, heavy duty radiators, One Tonners & 350 V8 engines.

 

I would recommend updating to a recovery system & an increase to 15 psi is always good especially for performance engines.

 

BTW, VN Onwards Commodore run a 20 psi system.

 

Dr Terry



#6 Bigfella237

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Posted 06 June 2020 - 09:35 AM

The higher the pressure, the higher the boiling point (that's why compressed gases, like LPG for example, can be stored as a liquid at room temperature), additives AKA "coolant" can also change the boiling point.

 

Modern engines tend to run pretty hot in terms of what we're used to seeing with the old red motors mostly due to newer emissions standards, but just remember that older style heater cores (under the dash) aren't rated for modern cooling system pressures, especially when they're 40+ years old!






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