6 replies to this topic

[Robdavmtb]

Hello everyone

 

Not long bought a mini (1983) and in the process of getting a few things sorted.

 

The previous owner has fitted a 1380 and a aluminium radiator.

 

I find the radiator cap lets water out (rated at 1.1) the system is not pressurising though, and when the engine cools you can hear the cap sucking air back in.

 

The cap has two rubber seals and i was wondering if it was meant for the later minis that have an expansion bottle.

 

I bought a new cap but as you can see in the picture it is alot bigger.

 

What are your thoughts? fit an expansion bottle? can i get another (1 rubber seal) cap for the rad?

 

Many thanks

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Edited by Robdavmtb, 11 April 2016 - 08:36 AM.

[nicklouse]

1.1 Bar should be fine as it is 15 PSI

 

but it does sound like it is not actually sealing.

[carbon]

The cap with the two rubber seals looks correct type for your radaitor. It's only the smaller seal which keeps the cooling system under pressure.

 

There is no expansion tank, so you need to have some air space at the top of the radiator to allow for coolant level increase when it's hot.

 

If it's too full then the excess coolant will be vented. With mine it tends to run about 1/2 inch below the top face of the radiator.

[dklawson]

As Carbon said, there needs to be a little air in the header tank.  If the radiator is 100% full to the top, it will let coolant out.  However, it looks like the radiator does have an overflow tube nipple on the filler neck.  Could you not buy a generic overflow bottle and tubing and fit it to refill the radiator on cooling?

[Robdavmtb]

Thanks for this.

 

Carbon, 1/2 inch below the fins of the radiator?

 

I have made up a temp solution of a coke bottle on the end of the overflow tube and i will see how this goes.

 

Cheers

[dklawson]

Remember when placing the tubing from the filler neck into the Coke bottle that the tube needs to go to the bottom of the bottle, not just into its neck.  The idea is that vacuum created as the cooling system cools down will draw fluid from the bottle back into the radiator header tank.  If the overflow tube doesn't go to the bottom of the bottle all that happens is you draw air back in.

[carbon]

Thanks for this.

 

Carbon, 1/2 inch below the fins of the radiator?

 

I have made up a temp solution of a coke bottle on the end of the overflow tube and i will see how this goes.

 

Cheers

The top of the fins has to be covered, the half inch level is below where the smaller rubber seal on the rad cap seals against the radiator.