Very nice setup. Clean looking install. I cant believe you have not seen a bigger drop in temps even while not towing.
Don't forget, the thermostat opens at 200, so temps will always be above that. Also, the 25-row SUSA cooler is just not big enough, IMHO.
Once I get the trailer on, that'll be the test! And getting the larger 60-row "Earl's" cooler on there will make a great difference, I'm certain.
Cant really beat liquid to liquid for efficiency.
Yes, that's true, liquid-to-liquid is better. But then I would be imparting even more BTU's into the coolant, and then that would require a bigger cooling system radiator. Heat is heat... just gotta get it out! LOL
But you really don't have anything to worry about unless your oil temps get up to 300F or so. Even at 250F you aren't really hurting your oil (or your engine). Like 79jasper said, a liquid to liquid cooler is way more efficient than liquid to air.
my 2 cents worth anyway.
I know 240-245 is not THAT hot, for modern engine oil. But, cooler is always better. My experience with industrial engines and hydraulic systems makes me lean towards keeping everything around 215-230. Oil life begins to drastically shorten once temps reach into the 240 range and above. Even modern synthetics, while much tougher than their predecessors, will begin to degrade much faster as the temperature increases above 240. In the last 30 years of wrenching, I've been through hours and hours of trainings and seminars, on industrial engine and hydraulic systems, and this is what I have gleaned from that.
Modern auto manufactures run the oil much hotter than they used to. It's part of the "designed obsolescence" (IMHO)... after all, they don't want their engines to last TOO long! LOL
And yes, liquid coolers are more efficient, however, in the end, it all ends up in the air (since this isn't a boat!).
Anyway, thanks for the positive feedback. I appreciate it. Time will tell as to how well it works!