Joined: May 2019 Posts: 3 Threads: 1
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Location: Haddenham
Car type: 1934 RP
Hello, can anybody tell what the two small (about 1mm diameter) holes are for in the radiator neck (where the filler cap fits). I have found that when my cooling system gets too hot then it spurts rusty water out of the two holes over the bonnet. I thought that the expanding water should leave the radiator via the overflow tube that can be seen in the radiator header tank but on my car it seem to prefer jetting out of the small holes. So I would like to seal off these holes, any thoughts?
Joined: Aug 2017 Posts: 1,462 Threads: 26
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Location: North Yorkshire
Are these the holes that should have small pegs in them that the radiator cap engages with?
Steve
Joined: May 2019 Posts: 3 Threads: 1
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Location: Haddenham
Car type: 1934 RP
No Steve, there are four pegs for the cap to engage on and two holes. I will try and add a photograph
Joined: Jan 2019 Posts: 1,565 Threads: 20
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Location: Bala North Wales
Car type: 1933 RP Standard Saloon
I don't think that the holes should be there. My RP radiator hasn't got any. My rusty water comes out between (imperfect and home-made) seal on the cap and the top of the neck. However, since I have flushed the radiator out and discovered that the level in the header tank should only reach the bottom of the semicircle below the filler neck when the engine is hot, I have considerably lessened the problem. And the water level doesn't need topping up nearly so frequently.
Joined: May 2019 Posts: 3 Threads: 1
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Location: Haddenham
Car type: 1934 RP
[img]IMG_3099.HEIC[/img]
Hello David, I think you are right in saying the holes shouldn't be there. The radiator is not a very authentic one and I think they serve no purpose so I will seal them up. Many thanks.
Joined: Aug 2017 Posts: 2,400 Threads: 33
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Location: Deepest Frogland 30960
Car type: 1933 RP Standard Saloon
To prevent coolant splashes I always smear some clear silicone around the rad cap seal and the rad top, to ensure that any splashes either stay inside the header tank or go down the overflow tube. Make sure of course that the overflow is free. I have stuck a piece of rubber pipe on the bottom end that passes between the damper arms so that any drips don't go anywhere other than on the deck. The bit about not filling any more than the bottom of the cut out is a good point.
Joined: Aug 2017 Posts: 2,748 Threads: 31
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Location: Auckland, NZ
Water loss under braking is unavoidable. A discreet catch tank (not plastic) enablee expensive fluid to be returned. 9Very effective inespensive non antifreeze additive was/is available here)