G'day,
Run into a bit of a problem with the drain plug on a C-ARA4442 radiator today. First time I've drained the radiator after running in on water and now ready for coolant.
The plastic plug was very tight to undo and it looks like it has been cross threaded when it was assembled (new radiator). No matter how many times I've tried, I can't get it to screw back in - the plastic threads are buggered. Starts off ok but cross threads again about half way in.
Just wondering if anyone knows what thread is on the drain hole? As I understand it, the drain hole also allows for fitment of the sender for a fan switch which is part number C-ARA4445 I think.

I've tried a 7/8" UNF but it's not that. Would the thread be metric perhaps - maybe a 22mm?

I don't really need a fan sender and am looking at just a plug of some sort. Either that or a bush that would allow me to screw in a tap like the original one would be good.

Cheers, Rocky

The general opinion is 22mm x 15 but Ido not know for sure, However this may help

https://www.minispares.com/product/Clas ... o%20search

Do you have access to thread gauges to test.

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Cheers Dave.

Thanks for that Dave. I searched for the replacement plugs on the minispares site but couldn't find them. The boss would say I must have had a "man look"

I don't see them listed on the minisport site. I'll check with Karcraft and see what they have. I'd reckon I'm not the only bloke who would need a replacement plug. The plastic ones seem to damage pretty easily. A brass one would be the go.

I don't have any thread gauges to check the radiator. Access is a bit tight with only about 2" between the radiator and body.

Cheers, Rocky

There’s also a fan switch that should fit, hard to tell from the photo but it could be one piece brass on the threaded side?

http://www.minispares.com/product/Class ... 0catalogue

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Thanks Timmy - that looks like it should fit. Would be better than the dodgy plastic plug. Hoping that if I can ascertain the thread, I'd be able to get a sender like that to suit at my local autopro.

Rocky

Something like this perhaps if I can't get a suitable plug.

https://www.tridon.com.au/products/Trid ... 272/TFS100

If it helps, I recently replaced my chewed out radiator drain plug with a brass one, it was 1/8" BSP from memory and went in fine.
Mine was a parallel thread (not taper) and I put an O ring on it to seal - no leaks so far (fingers crossed).
BSP threaded fittings can be found at any plumbing/irrigation store or even Bunnings might have them.
[EDIT] sorry that won't help - different radiator.
1/8" is nearly 9mm OD and you're trying to fill a ~22mm hole - my bad!

This is the relevant section of the drawing for the radiator used in the Australian Clubman/Leyland Mini - AYG2244. Don't know if yours is the same or not, but this may help.

_________________
ex-NSW Police 1970 MK II Cooper S
VMCI #43

From memory I think the thread in the radiator is straight not tapered. I vaguely remember a rubber sealing ring around my plug.
Agree not much space to play with

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1969 Cooper "S"
1967 Mini Deluxe
1973 Clubman Van (the fleet spare)
1978 ex 1275 LS ("Wizard" Eaton Supercharged)
2015 HSV GenF GTS(occasional drive & tow car)
2019 MINI F55 Cooper S

Thanks Soldar and Winnabey.

The radiator I've got is a new one - part C-ARA4442- and unlike my original one, doesn't have a drain underneath with a drain cock but has a drain on the bottom corner at the front of the car. The corner is on a 45 degree and the drain comes out of that 45 degree bit. It's a bit tricky measuring the hole size in the radiator but it's around 20.6mm. The outside diameter of the plastic (nylon?) bung is approx 21.7mm.
According to the minispares website, the radiator comes with wither a bung like mine or is fitted with a thermo fan sensor for the later model cars. I've been trying to find out the thermo fan sensor part number = to the part numbers quoted by minispares but no luck yet. This is the sensor that I think fits the drain hole but there's no specs listed for it. I've found lots of fan sensors with M22 x 1.5 threads but nothing listed under Rover Minis.

https://minisport.com.au/mini-radiator- ... ch-uk-cars.
Could get one of these but with postage it's up around $65 which is fairly dear for a plug.

If the thread is M22 x 1.5, I've found a brass plug similar to the one in the link at a hydraulic joint 100km down the road. It's fitted with an O ring to seal. $7 each. I'm heading down there tomorrow to get one and hopefully it fits. It's a pity that the new radiators aren't fitted with something a bit more robust than the plastic bung from new.

http://www.spraymart.com.au/metric-hex-plug

I've also tried the local wreckers and radiator joints to see if they had any old sensors that would do the job. No luck so far. I'll let you know how I go with the brass plug.

Rocky

Yes Michael - the thread is straight, not tapered so needs a bung with a collar with either an O ring or gasket like a sump plug. By the way, tried to get a M22 sump plug but none in town. Stocks of 20 and 24 but not 22.
Would have been OK to check thread but being metal, not brass, would corrode over time I reckon.

Just an update on the plug - got the brass one and can confirm that the thread is metric - an M22 x 1.5.

Fitted the new plug and filled with Penrite 10/10ths race coolant. Minnie's back on the road.
Thanks for the help.

Cheers Rocky