[Tom Wells]

Mike,

My 521 overheated when I first got it, usually when I stopped for gas which does happen fairly often LOL

Your car's cooling system may or may not be like mine, which has the fill cap below the level of some parts of the hoses.

You say you burped the cooling system, which is how I prevented mine from ever overheating again.

Here's how I burp mine:

When I fill the radiator after draining it, it will take a minimum of five burping and heat cycles to get rid of the air.

With the engine cold, squeeze the upper hose to get all the air bubbles out, adding coolant as needed to get the level back up to the top of the filler, then squeeze some more, add coolant etc.

Make sure the overflow bottle is relatively full and there aren't any leaks in the overflow hose or cap.

Then run the car up to operating temp. After it cools, remove the filler cap and burp more air out - and yes, at first there's more air...

Repeat this process five times! It'll take more than a day to do it, as the car really needs to be cool before the filler is opened again.

If I do this process thoroughly, overheating doesn't happen. I can take the car and idle along in a parade for literally hours without getting above 100C even on a hot day here in Florida. Absent the multiple burping process, the car wouldn't last 15 minutes...

Hope this helps.

If not, how about putting up some specs and photos of your cooling system so we can take another shot at it?

BTW, 460s use two gaskets and a backing plate between the water pump and the front cover. If the backing plate isn't there, the thing will surely overheat.

Let us know,

Tom