Fitted recovery tank, new radiator cap. Still loosing coolant from under radiator cap. Empties top tank but does not overheat. Any clues??? Anybody????? HELP!!!!!! MINI74

what BRAND radiator cap did you buy? I had problems a while ago and even though I had the right part number, a brand new Tridon brand cap didn't work, but a CPC one did - see here: http://www.ausmini.com/forums/viewtopic ... diator+cap

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I agree that the radiator cap may be incorrect, go with the CPC brand and see if that sorts the problem out.

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Mini, its in my blood........

Have tried CPC 13/90. The original cap is same brand and same pressure but the original cap has a shorter 'neck''. Both are exactly the same to look at except for the length of the neck.

the original has a shorter spring & shaft (neck) than the new one?

is it harder to get the cap on now?

does it seem like you've gotta crush the spring completely to get it on the radiator?

which one from the photos in the thread I linked above is your new & old?

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answer to questions

Yes
Yes
Yes
short new long old
both caps let water out between radiator and cap, but vehicle doesn't overheat

mini74

Get the longer neck cap. Short the wrong cap for a clubby. The radiator needs to be placed under pressure or else it will boil over and coolant will leak out the cap.

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Lillee - 1969 Morris Mini K

Thanks for that, will get longer cap. If doesn't fix what do you suggest?



Mini74

I thought you already had the longer neck cap

I'm confused

let us know if it doesn't work

could be lots of reasons why it chucks water out - maybe you're just putting too much in, maybe the radiator neck is damaged - the water in the engine always expands when it gets to operating temperature (physics!) so there needs to be some air that pressurises, then the radiator cap keeps the pressure in. We need to be able to vent that pressure as well, hence the right sort of cap & good condition

and an obvious question, how is the overflow/recovery tank fitted up, pictures might help - I'm not sure how they're meant to be configured, but usually you put the 'pressure' cap on the overflow tank, and a flat sealing cap on the radiator

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Sorry about confusion, got mixed up.
Recovery system is overflow going into plastic bottle (not pressurized), now water spewing out between cap and radiator neck, but doesn't overheat.
Could it be head gasket?
Sorry to be a pain.

when it's spewing water out, does it do it with the engine running, or after you switch it off?

if the radiator cap is to blame, it'll usually be after you switch the engine off, as hotspots in the head and the water not flowing cause the water close to it to boil and it escapes out of the cap...

if it's when the engine is running (and not overheating), then gas is getting in there



I was kinda thinking that, but wanted to be clear on the rest before bringing it up....

you should be able to CAREFULLY (disclaimer disclaimer) take the radiator cap off while the engine is running and see what it's doing. Fill it with water while its running and watch for bubbles, big burping bubbles, or masses of little white ones

maybe time for an expert to chip in

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To use an overflow bottle you need a recovery cap. They have a rubber seal around the side of the cap to seal on the neck of the radiator.

No bubbles while motor is running, but losing coolant when motor is turned off.
Thanks fellas.

the water level in my radiator stays at about 1cm above the core - are you trying to keep too much water in it?

whenever I add water, I fill it to the top of the tank, but it'll always settle to that level - 1cm above the core. I drove to Adelaide and back for Minis At The Mill - 1800km return, plus a fair bit of running around in hot weather in Adelaide, and I didn't add a drop before I left, and hadn't lost a drop when I got back (+ 2 weeks driving to work etc.)

When they were new, the radiators had a "water level" indicator plate in them, most have been removed and thrown away, but it was down from the neck, not far above the cores

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did I tell you that I won a trophy?

i had a issue with coolant bursting out after i turned the car off i found i could check if if the radiator cap worked by squashing the top hose with my hand a few times and feeling for air or fluid coming out the drain hole its a simple test which answered all my questions sounds like youve already figure this bit out tho. its good for when you buy a new cap tho and want to test it out the front of the store without going for a massive drive (providing your cars cooled down enough before you remove the cap just incase it is pressurising and the cap was doing its job)

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Enjoy Chris