Coolant query

[Mitchen]

Fellas I've got a coolant leak and the lights come on warning that the coolant level is low. Before I take it to BMW and they tear the arse out of my bank account, I need to fill the coolant up. Anyone know by chance what type of coolant I need? Obviously shouldn't just be picking anything off the petrol station shelf. I do realise this is a proper newbie question!

[PG325]

I believe you shouldn't mix colours. If you don't know what's in it, I would drain and refill with fresh solution.

[hongkongfuey]

Blue antifreeze/coolant

[Brianmoooore]

If its leaking, and about to be fixed, I'd just be putting water in there. Coolant costs money!

[Mitchen]

Would water be ok? If I topped it right up, it would probably be 95% water rather than watered down coolant.

[Brianmoooore]

If there's only 5% coolant left, you have a pretty severe leak! What makes you think it's as weak as that? There's 10 litres in there in total. If you top it up every time the light comes on, then you're only diluting it around 10% each time.
Any idea where the leak is?

[Mitchen]

Well I'm sure there was no leak, until I took it to Kwik Fit for the MOT a couple of days ago. After they passed the car, they told me it had a coolant leak, I then saw a puddle by the car and they told me it looked like it was coming from a hose leak or something. He didnt seem like he gave a toss tbh. I thought he was mistaken because before this I hadnt noticed puddles like this wherever I've parked. Wouldnt surprise me if they caused it when they were doing the MOT. I dismissed it as their mistake because I hadnt seen any puddles since, but then tonight after work when I started the car, the coolant light came on.

[Brianmoooore]

There's a short hose that goes from the back of the cylinder head to the bottom heater stub pipe on the bulkhead that leads a hard life and is often neglected because of its semi hidden position that's worth checking out.
Slow coolant leaks usually make a bit of a mess at the site of the leak, which should make it easy enough to find yourself, without paying some apprentice monkey at the dealers to do the same thing.

[Mitchen]

I'll give it a crack, I'm assuming if it is the hose, it's going to need replacing rather than any kind of repair job. Thanks for your help as always Brian!

[Brianmoooore]

It's not necessarily a leaking hose as such - it can be just a hose clip needs tightening, the alloy piece that the hose connects to at the back of the head can corrode, the throttle body heater gasket can leak, the thermostat housing can corrode, there's a steel pipe across the front of the engine that can rust, the water pump can leak at the pulley, or of course, radiators have been known to spring a leak.
Look for coolant stains.