My car started draining battery after the leaking head gasket was fixed. It worked nicely tuesday, but yesterday battery was dead. Had to jumpstart it and it again it worked nice. But today, battery was dead again. Battery is only 7 months old.

After jumpstarting, checked the voltage when car was running, 13.8 idling. Turning car off, voltage dropped little bit under 13v and every few seconds it dropped a little bit.

Removed battery cable and it voltage remained at 12.8. So battery and alternator are OK, I think?

Removed power cable of my amplifier and headunit, still kept dropping.

Have to check the fuses tomorrow. Is there any other reasons which can cause the draining? No electric windows, but it has a towing hook, which has some damage on its socket.

All tips and help are appreciated!

Try unplugging the alternator overnight or when parked up for long periods. Could be a leaking diode pack in the alternator which would still work when the engine is running. If the tow socket is damaged you should get that sorted asap.

Well, wasn't that big problem after all..

Tried 2 other batteries, both were rapidly draining. Multimeter showed 4,4A, and tried all fuses. Nothing.

Went through all the wires I saw under the hood and one of them was damaged by timing belt and had contact to the engine and car body. Covered it with electrical tape and multimeter showed 0,0A. Voltage remained at 13,4V.

Fixed!

Nice and simple!