1992 Aerostar Cooling System

I have a 1992 Aerostar with 3.0 L automatic. The cooling system appears to have an overflow tank located below the battery and behind the washer fluid reservoir. There is a hose that runs from the radiator neck to a small cap on top of the overflow tank. But I see no other way to fill this tank or even check the level. All my other cars have cap on the overflow tanks to allow for filling of the tank, but I can't find one on this Aerostar. Is there something I am missing or was this another way for Ford to save pennys per car. Any help would be appreciated.

I have a 1992 Aerostar with 3.0 L automatic. The cooling system appears to have an overflow tank located below the battery and behind the washer fluid reservoir. There is a hose that runs from the radiator neck to a small cap on top of the overflow tank. But I see no other way to fill this tank or even check the level. All my other cars have cap on the overflow tanks to allow for filling of the tank, but I can't find one on this Aerostar. Is there something I am missing or was this another way for Ford to save pennys per car. Any help would be appreciated.

I have a 1990 4L and the overflow tank is likely the same. There is a 1/2" flat grommet on the tank part that stickes out past the battery toward the engine. Remove the rubber grommet to fill the over flow tank.
TTFN