If under pressurising you might get coolant boil off earlier than you expected, especially if the coolant isn't good eg. mostly water. If over pressurising you have the risk of leakage or component failure. I'd be worried about expansion tank failure as this seems to be the general point of failure on other car makes where they used higher pressure caps.
Ok, thanks Jeff. Cap service is now on my list for spring when I next have the engine cover off. Thanks again, your videos are my trusted source for my 981s maintenance. Still building up the courage to do a coolant change 😁. Barrie
@@jeffrichardsoncardiyWell that's so interesting, especially important as aging plastic parts are subject to failure. It would be really cool if the cooling system had a pressure gauge! (pun intended!) to know what is really going on.
