<p style=”text-align: left;”> the cap on the expansion tank does it need to be sealed completely tight or does it need to be left slightly loose for air to escape?</p>
so if it is done up tight, to as tight as it can go if it over pressurised how does it vent,if the cap is closed tight ? sorry I am not a mechanic and don’t know much about engines etc etc.
its a closed loop system and the cap or something will be self venting at a certain pressure. all this stuff in the owners manual about why it should be tight.
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