310 Radiator Cap

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egrens
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Location: Virginia
Model: 1500/1600
Year: Low Windshield-64-67.5

310 Radiator Cap

Post by egrens »

I have a 1965 1500 roadster with sealed radiator (no overflow tank). Looking at other roadsters, I do not see many like mine.....my radiator is quite a bit larger and the radiator cap is on top of the radiator....not on the head. Mine began to leak/weep though the top indicating it was not 100 percent sealing at the neck of the radiator. I looked for a replacement in all the usual Datsun sites and could not locate one. After much research I found the Gates model 31527 fit perfectly......$7.91 on Ebay including freight. Thought I would share if anyone else is looking for a replacement cap.
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Nissanman
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Location: Adelaide, South Australia
Model: 1500/1600
Year: Low Windshield-64-67.5

Re: 310 Radiator Cap

Post by Nissanman »

Well done!
It is an easy stealth move to convert the 1500 system to a true sealed system with a pressurized overflow tank.
When it burps out coolant it is able to suck it back in, maintaining the system full of coolant, unlike the stock system which will progressively lose coolant to the outside world.
Nissanman, just trying to help.
1965 SP310 Engine No. G-93326 Car No. SP310-10817
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datsun1500
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Re: 310 Radiator Cap

Post by datsun1500 »

That cap is rated at 13 pounds. The 1500 should be 4 pounds. It’s not just about the fit. You will push out too much coolant and overheat.
I remember when no one wanted the 1500s......
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Nissanman
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Re: 310 Radiator Cap

Post by Nissanman »

That is a problem indeed!
But if I remember correctly, the SP310 is 7psi.
When I converted mine to a fully sealed coolant recovery system with header tank, I used a cap [Trico CA0750] rated at 7psi to match the system.
https://www.tridon.com.au/includes/imag ... roductHero
That was fitted to the expansion/header tank and a blanking cap [Trico TRC10] fitted to the radiator.
https://www.tridon.com.au/includes/imag ... roductHero
Product listing here: -
https://www.tridon.com.au/products/Trid ... tor-caps#1
Nissanman, just trying to help.
1965 SP310 Engine No. G-93326 Car No. SP310-10817
http://nissanman.shutterfly.com/117
On the road again!
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spl310
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Re: 310 Radiator Cap

Post by spl310 »

Nissan man, the 65 1500 (your car) has the most number of unique parts. If I recall correctly, the three seat cars are lower pressure as Mark indicated. The 65 may be unique for the cap (I think so, but I am not sure). The later cars went higher.
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steve_car
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Re: 310 Radiator Cap

Post by steve_car »

The 63 and 65 Parts Catalogs both call out the same part number 21430-30001, a 7 psi cap. The early 320 truck uses a 4 psi cap that is the same physical size as the 1500 cap. These caps are a different size than the 1600 and 2000 blanking cap.
Steve
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62 L320
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datsun1500
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Re: 310 Radiator Cap

Post by datsun1500 »

Might be 7, might be 4, but it’s not 13. One of the most common reasons for a 1500 to overheat is wrong cap. It’s also one of the most overlooked, people start throwing parts at the issue not realizing the pressure matters.
I remember when no one wanted the 1500s......