I have about 60k on my E and had some problems with the factory coolant. I got air bubbles in it and change it out with prestone universal. Since I changed their have been no air bubbles and no coolant loss. I was thinking of changeing out again because all I did was a drain and fill. I dont know if I should use prestone, honda, or amsoil? I've heard good things about the amsoil coolant but what do you guys think?