Best way to clean expansion tank after head gasket failure??
 

I have just had the head gasket repaired on my 120 but was wondering how i could clean up the expansion tank? A system flush did help to start with but the tank is getting slightly oily again from what i assume is the remains of some left over oil in the system. I was going to get a new expansion tank but want to leave it long enough for some more of the oil to come out..

Thinners and give it a good shake and flush through

Dishwasher if you have one.

pressure washer and a good degreaser, also worth using a little brush similar to a chimney sweepers brush but smaller lol

I think you're talking about a bottle brush...?

thats the one lol

just go to a breakers and get another one for about £5

Bleach.

Remember your whole coolant system will be full of gunk not just the expansion tank so you'll need to flush the whole lot. Pointless doing just the expansion tank as soon as you drive the car it'll be full of gunk again.