Getting a faint coolant smell after driving my 2015 F32 435i hard. No visible puddles under the car, coolant level hasnt dropped noticeably, no overheating. But the smell is definitely there, especially when I park in the garage.
N55 engine with 88k km. Where should I start looking? I know these engines have a few common leak points.
On the N55, the most common coolant leak spots are:
Since you smell it but cant see it, my bet is the expansion tank. The cracks are tiny and the coolant evaporates before it drips. Use a UV dye kit to find it.
Pressure test the cooling system. Rent or buy a cooling system pressure tester (about 50 EUR). Pump it up to 1.5 bar and watch for pressure drop. Then inspect with a flashlight.
Also check the charge pipe to intercooler connection. On the N55 the charge pipe can crack and if coolant is leaking near the turbo it evaporates instantly - you smell it but never see it.
had this exact symptom on my N55. turned out to be the electric water pump weeping from the electrical connector. very small leak that only happened when hot. replaced the pump and smell went away.
the pump is about 250 EUR aftermarket and maybe 2 hours labor.
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