Another improvement, introduced with the Merlin X, was the use of a 70%–30% water-glycol coolant mix rather than the 100% glycol of the earlier versions.
En yderligere forbedring, introduceret med Merlin X, var anvendelsen af en 70 % – 30 % vand-glykol blanding af kølevæsken, i stedet for den tidligere anvendelse af 100 % glykol.