JISUMOTO JISUMOTO new Degas (Coolant Overflow) Bottle and is made from 6061 aircraft grade aluminum which is TIG welded and pressure tested for maximum strength. This fabrication method makes JISUMOTO tank significantly stronger than factory tanks which are molded from two plastic pieces which are sealed together causing stress, cracking... JISUMOTO JISUMOTO new Degas (Coolant Overflow) Bottle and is made from 6061 aircraft grade aluminum which is TIG welded and pressure tested for maximum strength. This fabrication method makes JISUMOTO tank significantly stronger than factory tanks which are molded from two plastic pieces which are sealed together causing stress, cracking...