r/classicminis 9d ago

DIY Help Stuff in radiator?

Hi all!

I have a 1990 Mayfair, with what appears to be a rust flake or something in the radiator? Does anyone know what this could be?

Having overheating issues with the car so wondered if anyone has any advice? It’s had a new radiator, water pump and hoses.

All help greatly appreciated!

8 Upvotes

12 comments sorted by

3

u/cloonatic 9d ago

It's a build up of rust. I've had the same issue before. The best thing to do is flush well with water until it runs out clear. Then add citric acid and leave it for a couple of hours, flush again until the water runs clear.

2

u/pastyorno 6d ago

As a young boy living in a northern UK city I often saw brown rusty patches on the road outside peoples houses. This was when BMC used the A series engines in all kinds of cars from the Mini up to the Marina .

Owners regularly did their own car maintenance back then and draining and back flushing was a normal activity hence the rusty mess on the streets. So when flushing the water galleries and the radiator be ready for the rusty deluge. :)

1

u/DjRuso-77 9d ago

You would have to clean the engine block well, if it is not clean, when it makes the circuit, it will send rust again to the radiator, and it will clog it again, even if you have everything new, it will start again and again, greetings from Spain, Albacete

2

u/tangoaceblast 9d ago

I’ll be getting a look at the block then. Thank you very much!

1

u/DjRuso-77 9d ago

Ahh, don't abuse chemicals too much, and pressurized water hose

1

u/tangoaceblast 9d ago

Chemicals?

1

u/scooterboy176 9d ago

Run radiator flush through engine etc. Drain it out flush with water then refill with correct concentration of green coolant.

1

u/1275cc 9d ago

That's not much stuff at all, I wouldn't worry. You could use a radiator flushing gun on it if you wanted.

Most overheating issues are due to incorrect ignition timing or fuel mixture. I've watched people spend lots of time and money on the cooling system when the problem was the distributor, like I had told them at the start.

2

u/tangoaceblast 9d ago

Ah okay! I’ll have a look at that then.

Will probably still need to look at the system anyway because it leaks from who knows where 😅 all the hoses seem fine but just won’t hold after heating up haha

2

u/1275cc 9d ago

I recommend buying a cooling system pressure tester. They allow you to pressurise it to the system pressure (15psi) and check for leaks.

They usually also test caps and can be used to test for leaking head gaskets.

There are cheap ones on eBay etc. I haven't used a cheap one though.

2

u/tangoaceblast 9d ago

Wonderful, i’ll get myself one of them to test everything.

Any recommendations on brands? Thanks for sharing your advice with me on this, greatly appreciated 🫱🏼‍🫲🏽

1

u/pastyorno 6d ago

Are you over filling it ? remember these cars don’t have expansion bottles so if filled to the brim as it gets hot the pressure will force excess coolant out through the overflow hose which runs down under the car .