Because engine coolant recovery tanks are typically made of plastic, having one crack on you is not uncommon, especially if you're a rigorous build-break-repeat Jeeper. Fortunately, 4WD carries a full line of coolant recovery tanks, also called radiator overflow tanks or coolant overflow tanks. If you've already cracked a few you may wish to go all in with a metal recovery tank from Be Cool, Mishimoto, Mr. Gasket or Flex-a-lite. Metals available include polished chrome, polished aluminum, natural aluminum or polished stainless steel. On 4WD you'll also find the yellow "warning" reservoir caps with the "Engine coolant only" text written on the top.