[LUX3]

I have owned this 5 year old 330i for a year and driven it about 5000km, the car now has just 27000km on the clock.
So I check the engine coolant regularly and have so far added near 2 litres over the year. The intercooler coolant level has not dropped.
Never seen any leak on the garage floor or smelt any hot coolant around the motor.
This can't be normal. Where is it going?
Anybody had this problem?
I guess the next step is to get a pressure test on the system?

[Aussiefalcon]

You could try cleaning any white residue around the filler neck. Then apply a tiny smear of silicone grease inside the filler neck where the "O" ring seals. Also a new cap may be a good investment. "O" ring can become hard over time. Please let us know results.

[LUX3]

Thanks for the suggestion.
But the filler is clean, no residue.
Unfortunately, that would have been an obvious fix .

[adge7]

I had a similar issue, except a low coolant warning would pop up on occasion. During a service, I mentioned it to the mechanic and they tested the system and confirmed there were no leaks. They swapped the coolant reservoir cap for a new one and that fixed the problem.

[LUX3]

Apparently this is a "thing" with B48 and B58 motors. As per Google search:

"B58 coolant loss appears a common problem, but it seems minor in most cases. Don't sweat it if you're only topping up small amounts on occasion."

[LUX3]

WATER PUMP LEAKING at 28000km!!!!
Finally detected by BMW techs. Just remove the lower cover and look at the water pump for crystal deposits. This leak was NOT detected by pressure test.
Must be some sort of record, failing at such low km.
So much for buying expensive quality vehicle!
😒

[Aussiefalcon]

At last you have a diagnosis. Pretty rubbish quality component though.
Thanks for letting us know.

[JBT2]

Pathetic quality. No wonder BMW only have a 3 year warranty. They should repair this under good will.

[LUX3]

Originally Posted by JBT2

Pathetic quality. No wonder BMW only have a 3 year warranty. They should repair this under good will.

"Good will" - makes my blood boil..
When I bought the car a year ago from a car dealer, it had 23000km and was supposed to have statutory warranty.
I reported the coolant loss issue right after buying it, and the dealer's response was "it's not covered"!!!!
So now I've got a $big repair bill.
Leaves me with a sour taste in my mouth for sure.