MINI One - Problems with cooling system - tweb

Recently I've been having some problems with the cooling system.

The temperature gauge has been going all over the place, the fan is on pretty much the whole time I'm driving and stays on for about 2minutes after I turn off the engine, despite not being that hot.

The water also seems to be disappearing, I top it up everytime I drive and after driving, the water cap is up, often has steam coming out and there's considerably less water in there.

There's also been a grinding noise recently, usually after I've been driving a while and sometimes after I turn the engine off. I've tried to hear where it's coming from but by the time I've popped the bonnet it's stopped.

I've had both the temperature gauge and water pump replaced but still having the same problems.

Any ideas?

MINI One - Problems with cooling system - thunderbird

If its steaming, using water and making grinding noises STOP DRIVING IT AND GET IT TO A GARAGE. If youa carry on you will potentially wreck the engine.

Take it to a different garage, its clear yours did not have a clue.

MINI One - Problems with cooling system - Cyd

Yeah, I'd second that.

MINI One - Problems with cooling system - Cyd

Sounds like the cap may have lost its ability to keep the system pressurised. Without the required pressure in the system the boiling point of the coolant is reduced (to about 105C). Water may be boiling away as a result (probably around the exhaust valves), escaping from th ecap. Adding more water and diluting the coolant further (towards being only water) makes this worse because the boiling point of water is even less (100C) and so it gets worse.

Presumably this is a petrol engine? Is it turbo (even higher exhaust temperatures!!!)?

The gauge varying like that may indicate either an air lock moving round or steam bubbles (no coolant round the temp probe).

MINI One - Problems with cooling system - Collos25

I think the grinding noise is a worry could well be the water pump.

MINI One - Problems with cooling system - madf

Don't drive it without a new radiator cap.

If it still has problems, then find a competent garage .

If it has no problems after a new cap , find a new garage to fit new antifreeze. Yours will al have gone. One hard frost and ice..

You are doing your best to destroy the engine and have £1000s bills.

MINI One - Problems with cooling system - Ollie102
Hey, I'm having exactly the same problems and am currently stuck at the road side as my car was steaming so much. What was the problem in the end so I can tell the garage and stop them charging me lots of un necessary stuff? Thanks!
MINI One - Problems with cooling system - unthrottled

The temperature gauge has been going all over the place, the fan is on pretty much the whole time I'm driving and stays on for about 2minutes after I turn off the engine, despite not being that hot.

Do you mean that the radiator isn't getting hot? Have you checked that you're getting a temperature drop across the radiator? ie the lower hose should be cooler to the touch than the upper hose?

If the coolant is being lost via boiling out of fthe pressure cap then most of what is lost will be water since water boils much more readily than antifreeze. So you can top up with water. Antifreeze only raises the boiling point of the coolant very marginally anyhow.

MINI One - Problems with cooling system - Cyd

Ethylene glycol anti freeze raises the boiling point of water at STP to around 102 with 30% and around 105 with 50%. The addition of pressure raises it further, typical system pressures of 1.4bar will raise it to about 120.

Loss of pressure via a faulty cap may be sufficiently critical in some engines (turbo petrol especially) to allow boiling around the exhaust valves. This prevents the coolant from carryng away the heat efficiently and the problem is quickly compounded.

I'd also recommend that once you've sorted the overheating problem, you flush the system with a proprietory cleaner and refill with fresh coolant.

 

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