[chrisveal]

So my 340i randomly dropped about 2 litres of radiator fluid yesterday at lunch (drove to lunch, about an hour for lunch, walked back to car and it was over the ground). I couldn't see where it came from, it also "sounded" like the water in the reservoir was boiling which seems odd/wrong as the temp never even got to 110C. I had no low level coolant warning or over temp either.
So I filled the system with fluid, bleed it and took it for a drive 30-40 min, got home, parked it up. I check post 30 min, no leak. Got up in the morning and it had dropped about a litre over night. It also is dropping in both reservoirs, I thought they were independent of each other?
Can anyone give some advice please?
Cheers

Chris

[BMWILUVU]

Originally Posted by chrisveal

So my 340i randomly dropped about 2 litres of radiator fluid yesterday at lunch (drove to lunch, about an hour for lunch, walked back to car and it was over the ground). I couldn't see where it came from, it also "sounded" like the water in the reservoir was boiling which seems odd/wrong as the temp never even got to 110C. I had no low level coolant warning or over temp either.
So I filled the system with fluid, bleed it and took it for a drive 30-40 min, got home, parked it up. I check post 30 min, no leak. Got up in the morning and it had dropped about a litre over night. It also is dropping in both reservoirs, I thought they were independent of each other?
Can anyone give some advice please?
Cheers

Chris

Pressure test the coolant system. Most of our leaks are (in order of most to least frequent):
radiator cap leak
reservoir leak
turbo leak

[chrisveal]

I have dropped my car off at Brisbane BMW, it turns out that the water pump has a leak and requires replacement.

[chrisveal]

Originally Posted by chrisveal

I have dropped my car off at Brisbane BMW, it turns out that the water pump has a leak and requires replacement.

Picked up my 340i today and can not fault the guys at BMW Brisbane. They covered the pump plus extras under warranty and my cars back home running sweet.

[cfm56d7b]

Originally Posted by chrisveal

Picked up my 340i today and can not fault the guys at BMW Brisbane. They covered the pump plus extras under warranty and my cars back home running sweet.

Glad it all worked out on the first service visit.

[misguided_will]

how many kms has your car done?

[chrisveal]

Originally Posted by misguided_will

how many kms has your car done?

Hey mate, my car had done 67k

[juld0zer]

Originally Posted by BMWILUVU

Pressure test the coolant system. Most of our leaks are (in order of most to least frequent):
radiator cap leak
reservoir leak
turbo leak

Don't take this the wrong way but I don't think this is correct. The high temp cap has been around for ages and is a proven design. They usually fail from oil contamination (yet to be common on B58) or mishandling (impact damage to the tip).

B58 F chassis cars usually come from the factory improperly bled. This will confuse a lot of people but a pressure test will yield nothing. Most should have been taken care of by now as this issue usually occurs within the first 15k
Next is either stone impact to the low temp radiator (the two circuits are linked) or the belt driven water pump leaking at either the weep hole or the reservoir cap on the pump.

B48 models are getting on with age and we are seeing the vent pipe to the cylinder head fracturing underneath the manifold. It's a crap design. Thermal cycling and vibration

[BMWILUVU]

Originally Posted by juld0zer

Don't take this the wrong way but I don't think this is correct. The high temp cap has been around for ages and is a proven design. They usually fail from oil contamination (yet to be common on B58) or mishandling (impact damage to the tip).

B58 F chassis cars usually come from the factory improperly bled. This will confuse a lot of people but a pressure test will yield nothing. Most should have been taken care of by now as this issue usually occurs within the first 15k
Next is either stone impact to the low temp radiator (the two circuits are linked) or the belt driven water pump leaking at either the weep hole or the reservoir cap on the pump.

B48 models are getting on with age and we are seeing the vent pipe to the cylinder head fracturing underneath the manifold. It's a crap design. Thermal cycling and vibration 🤦🏻*♂️

Lot of people have coolant residue around the cap. Mine did leak.