I was going to have the old radiator cleaned and flushed. I took it to the local radiator shop and as soon as pressure was applied we saw a pin-hole leak, the guy there then pushed his fingernail into the core and a new leak happened. You could almost cause leaks just by pushing on it with your finger. Radiators get old, it's just a fact and most of use have busses that or 20 years old or more. The best thing you can do to make your bus last is keep the motor cool. You can't keep the motor cool and running very long with an old clogged radiator. The material the core is made of just gets old and weak. HEAT KILLS MOTORS! Take extra care to make sure your radiator and water pump are in top working order before you go on any trip. That is why I replaced my radiator and water pump with new "in the box" parts.