E46 330d Battery Drain

[Mexman]

Strangely, my 330d seems all of a sudden to take forever to get to half way temperature on the guage, it seems quite happy to sit at a quarter.... this has only started happening in the recent cold spell?

[helix402]

Re op, your main thermostat will be broken. Also worth doing the egr thermostat at the same time if it has one. Don’t use cheap ones, they don’t last.

Re batt probs. It may not be a drain. Start with the basics, get battery tested not just a voltage check.

If its ok, then you need to check closed circuit current drain, when the car is in sleep mode. This should be around 30mA max.

The battery could be failing again, as could the hedgehog. Particularly if it’s a non gen one.

Drain probs are rare on the E46 so it may well just be a battery. My 330 original battery lasted 220k miles and 16 years!

[SebringMan]

Depends on what battery was fitted. Alot the cheaper ones and Bosch Silvers (S5s) fail within that time.

However, some do seem to last quite some time. Have you tried putting the battery on a charger? It will charge it more effectively than driving the car around.

if that doesn't solve it I'd check for a drain with a multimeter in line to the battery. Of course you won't be able to lock the car etc. but it will show a significant drain if one is present.