Originally Posted by SSEi_MN
me and a friend did our engines recently and used sink and basin cleaner..... it comes in a can and foams. spray it on... let it sit.... use a dish sponge with a scrubby side and mines brand new looking....
that cleaner worked for everything in the engine that was dirty
I think the problem was dirt and grunge on the _inside_ of the reservoir...
I cleaned mine by removing it from the car (was doing a flush-and-fill of the cooling system anyway), pouring half a capful of TurtleWax Liquid Car Wash in, filling it about half-full with hot water, and sloshing it around big-time. After some shaking and soaking, it came out spotlessly clean; looked brand new.