Talk Morgan Forums Morgan Sports Cars Morgan Plus Four, Supersport & Plus Six (CX & CXV Generation Vehicles) Coolant Dipstick

I am in the factory next week so if I remember I'll ask them. I am ok with a 50% solution filled to the line though.

Just in reply to this: https://www.talkmorgan.com/ubbthreads.php/topics/832743/re-coolant-dipstick#Post832743

In May 2023, they issued redesigned coolant tank caps (mine is a MY22 Plus Four). I was about to head off for a long trip and couldn’t drop the car off, so instead I was mailed a new coolant cap - along with instructions for how to refill the coolant:

“ Do this when the car & engine are cold - You need to open passenger side bonnet,
Take old cap off coolant tank, suck out all fluid in the coolant tank with syringe - bottle it all up, then put back exactly half a litre, and fit new cap. The warning sticker should also be fitted to the side of the coolant tank.

Less fluid gives less pressure. Should equate to it pressuring the whole system less. “

I didn’t dilute the coolant - used BMW HT-12 (Green). The 50% level warning sticker (as others have said) is the fill level, not the dilution.

My owners handbook says 50% by volume viz:-
Cooling System
The coolant expansion tanks and coolant systems are situated under the bonnet.
Under the left hand bonnet is the engine coolant circuit and under the right
hand bonnet is the low temperature intercooler circuit. Both coolant systems
should be filled to half way up the tank with HT-12 coolant and should be
inspected only when the engine is cool. It is essential that the engine is supplied
with sufficient water/HT-12 mixture at all times. In an engine of this type, HT-12
must be present in the water at all times. HT-12 should be kept at a minimum
of 50% by volume.

My manual says the same thing as John's.

Whoops - you are completely right, Clemens & John - I remember now that I did dilute the coolant 50:50. It was just the 50% sticker I recall being used to show the liquid half way up rather than full.