I have recently discovered that there are at least 2 types of rad cap that will fit on a mini radiator.

One is 'longer' than the other, but both have same pressure rating.

My new cap seemed to leak when I turned off the motor. This happened to me years ago with a Torana too. Not uncommon??

I have a lot of spares, and on a spare rad there was a newish cap, but the part that goes into the neck looked longer. I thought I would try it out.

Didn't leak when I turned the car off, so I thought 'great, I will use this one'.

It seems that the pressure in the cooling system was too much with this cap, and 1 or 2 welsh plugs started to leak with it. I have heard stories of welsh plugs BLOWING OUT with too much pressure.

So what cap is right? Or are there different rad necks that need different caps???

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Website: www.justanothermini.com

Jack Read
was showing me some smaller necked ones the other day that I think were for when you have an overflow resevoir fitted.
Cheers Gerard

If radiator is full it is common to push some out when it gets hot. Water expands..
If you use one that's too long, it will be infinite pressure not 13psi, you will blow welch plugs, radiator hoses, bypass hoses..
Ask kazjim, he knows.... harhar

<edit> if you expect it to suck back from that plastic header tank you have, as it cools- you need a cap with an outer rubber seal. Minis don't have this... so good luck.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Yea the theory behind me fitting that plastic tank was to catch the coolant that was expelled from the rad.......so it didn't splatter on my nice shinny undercarraige

I never expected it to be sucked back in....although if my memory serves me correctly, Jill from WA has a rad / cap that sucks it back into the rad from an overflow bottle.

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Website: www.justanothermini.com

I had a overflow bottle on my old LS years ago. fitted the rad with a Flat cap and the overflow bottle(out of an 1100 or moke) with a pressurised cap. Never dropped any fluid and rad was always full after fitting. No drama's with overheating due to lack of water after that.

Cheers

Aaron

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Anton i use a cap from a holden v8 same presure as the mini one but it set up for a recovery tank works well it did leak a little but a bit of white teflon tape on the rim sorted it out
Cheers

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ooohhhh......part number??

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Website: www.justanothermini.com

Just check the neck length..
My Fiat 124 had a similar one, they do work well if no vacuum leaks on the hose or cap.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

it has D7 stamped on the centre pin and recovery system stamped on the bottom

was for a 308 kingswood HJ

cheers
gadget

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the mini's or mokes with the recovery system had a flat cap with no spring am i correct or was that atop the recovery bottle
makka

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Anonymous moderation means the agro that is built up towards the mods isn't aimed at an individual (fewer "Makk" attacks). Less stress for mods means less moderator "retirements".

ta

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Website: www.justanothermini.com

Yeah but that's a different recovery system, also used on XJ6.
Anton's now has a plastic overflow tank, as used on most modern cars. Pressure cap is on the rad and a vented one on the bottle.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

no worries always good to help a nOOb out

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bah ha ha ha ha

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Website: www.justanothermini.com

my newish radiator cap takes a bit of effort to put on, take it this might be too much pressure. Should i swap back to the oldy? I dont seem to lose any fluid at all.