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TR2/3/3A TR3. Radiator Cap

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CJD

CJD

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Just wondered what everyone is using for a pressure rating on their caps. The original is pretty low, but are there any problems with using a higher pressure cap?

Thanks,

John
 
I use the correct (4#?) cap -- car never overheats and I figure the 50-year-old rad doesn't need the extra pressure. I'm not even sure you can get a higher pressure cap with the longer reach you need for that filler neck.
 
ISTR the early TR4 used a "long reach" cap rated for 7 psi.

I had the radiator shop install a "short reach" neck, so I can use almost any common cap. I'm currently running 10 psi just because I like having a bit more margin before the coolant boils. But my radiator isn't 50 years old, either.

I've heard that the original pressure was so low because the original "aneroid" type thermostat tends to close as the pressure goes up. But I've never tried it.

Only other concern I can see is the original round-core heater may not be able to take the extra pressure. But mine is safely on a shelf in the garage, so I don't worry about it :crazyeyes:
 
Have been running a TR4 7-pound cap in my TR3, with heater, for a couple of years now. No problems.
 
Howdy Folks,

I just recently asked my Brit Car Guru Mech. the same question.

He says; If its a stock, Orig. set-up; The "4lb" cap is suggested with the "Long Reach".

He spec. out a "Stant #10205" that can be purchased from "Advanced Auto" etc. They will probably have to ord. it for you as its not a stock item.

I`m going to find out today the cost, availability etc. & will advise.

Regards, Russ
 
Well, check it out carefully. Last time I ordered the Stant cap that was listed for TR4, it turned out to be a short reach cap for a late TR4.

Amazon claims they have 3 left in stock, for $.94/each :smile:
 
Hi Randall,

"Amazon"?? Whats the website or any contact info?

"$.094"; Really! Heck, I`ll buy all 3 they may have just for the heck of having them.

Thanx, Russ
 
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