i used the ford yellow coolant. Thats what yours has in it now. you can replace it with the yellow but you NEED to still add the sca additive, even though fors says you dont. It took 2pints for mine to get up to par. Ive heard the CAT ELC is about the best. You have to get darn near every drop out of your system to get the full benefit. I believe it is a 300k coolant and needs zero additive. If i were to do it over thats the route id go