radiator caps

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Sloppy 2000
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radiator caps

#1 Post by Sloppy 2000 » Mon May 15, 2017 6:31 pm

Hi,

I have had cooling problems (correct that), my mk1 has had cooling problems. The radiator I have bought looks slightly different. Mine is more square and this is rounder and has slight horns, What I need to know is, How do I choose the radiator cap. Some cars had 7lb and some 13lb caps (i don't know for sure but think this is the case). How will I know which one? Were they stamped anywhere. Currently the one I have is 7lbs
Is the pressure down to the pump or down to the radiator?

Jeff
Triumph 2000 estate mk1 1968

Mike Stevens
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Re: radiator caps

#2 Post by Mike Stevens » Fri May 19, 2017 8:55 am

Hi Jeff,

The pressure is down to the water heating up and expanding in a sealed system. Having a higher pressure allows a higher coolant boiling point.

As to the correct cap, I have a feeling that it should be 13lbs, but it may be that Mk1 cars use a 7lb and Mk2 13lb, but I am not sure. Hopefully, one of our Mk1 experts will be along to advise!

Cheers,
Mike.
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David Withers
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Re: radiator caps

#3 Post by David Withers » Fri May 19, 2017 6:11 pm

From distant and unreliable memory of the 1965 Mk 1 that I ran from 1970 to 1975, it was fitted with a 7 lb cap. The Mk 2 had a 13 lb cap. The two caps differ in the shape of the lugs and slots so that only the correct one will fit.

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Re: radiator caps

#4 Post by Dazzer » Sat May 20, 2017 5:01 pm

Use the 13lb Ive used both on my MK1 didnt overheat with either just gives you a little higher boiling point with the 13lb and they are more common as well.

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Re: radiator caps

#5 Post by Dazzer » Sat May 20, 2017 5:11 pm

Use the 13lb Ive used both on my MK1 didnt overheat with either just gives you a little higher boiling point with the 13lb and they are more common as well.

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