My 525i seem to be losing a little coolant... advise?

[525iZA]

Well, yesterday morning when I fired up the car, I got the COOLANT LOW message in the instrument cluster.

Opened up the bonnet and coolant level was indeed low. Off to a service station and topped up coolant. Thing is, I cant seem to make out where the max mark on the bottle is.

Anyhow, this morning before starting the coolant level was about 5mm lower than the level that I filled it to the day before.

Checked it again now when I parked the car. Must be about 2cm lower than the level filled to on yesterday morning.

I've looked around the engine bay and I can not see anywhere where the cooling system leaks coolant. Not a single drop on the floor after standing a while either.

Opened oil filler cap and luckily no "mayonnaise" in there.

Where could the coolant be going? Should I be concerned? I'll obviously be monitoring this closely.

[whiskychaser]

Well, yesterday morning when I fired up the car, I got the COOLANT LOW message in the instrument cluster.

Opened up the bonnet and coolant level was indeed low. Off to a service station and topped up coolant. Thing is, I cant seem to make out where the max mark on the bottle is.

Anyhow, this morning before starting the coolant level was about 5mm lower than the level that I filled it to the day before.

Checked it again now when I parked the car. Must be about 2cm lower than the level filled to on yesterday morning.

I've looked around the engine bay and I can not see anywhere where the cooling system leaks coolant. Not a single drop on the floor after standing a while either.

Opened oil filler cap and luckily no "mayonnaise" in there.

Where could the coolant be going? Should I be concerned? I'll obviously be monitoring this closely.

The 'max' mark is about half way up the bottle. Its the one with the longer line but its a pain to see. Have a look at the chanel under the rad - a little weep might collect there. Feel round the back of the water pump pulley to see if the pump is weeping. Assume you checked hoses. You probably know these motors dont like to get hot. Do be aware that the low coolant warning wont come on with the engine running

[525iZA]

The 'max' mark is about half way up the bottle. Its the one with the longer line but its a pain to see. Have a look at the chanel under the rad - a little weep might collect there. Feel round the back of the water pump pulley to see if the pump is weeping. Assume you checked hoses. You probably know these motors dont like to get hot. Do be aware that the low coolant warning wont come on with the engine running

Thanks! I know these engines are a disaster waiting to happen when the cooling system isn't up to scratch.

In that case, I think I overfilled and the excess might just have drained away. Phew!

Will poke around a little more and see what I can find.

[e34.535i.sport]

The radiator cap could be letting some out as vapour... I know some e34s had a recall and replacement on them due to a fault... Might be worth a phone call to BM if you cant find any trace?

[Dr. evil]

i had a similar problem. turned out the raditor had small leaks in it, you could barly see it but the atifreeze gives it away

anouther good place to look is the bottom of the coolant resivor. some times the large o ring will start to leak