Lehman 120 cooling hose collapse
I have twin 120 Lehmans. On the port engine, the large diameter cooling hose coming up to the expansion tank on the port side of the engine collapses when the engine cools down after a normal 185 degree engine run. After the engine has cooled, I open the expansion tank cap and the hose comes back to normal. When cool, the coolant level is just below the bottom of the cap and the same as the starboard engine which does not have the collapsing hose issue; and I lose no coolant during running.
Any ideas what is going on? I do not have the tank coolant recovery upgrade done on either engine.
If it is cap related, I could swap starboard and port engine caps and see if the problem moves to the starboard engine hose...