I did try a search, but there are so many threads about oil temperatures, and none of them addressed anything similar to my concern, so I posted a new question. I have a built small block (417ci & around 500hp) in a 1987 Corvette, with an Earl's "Temp-A-Cure™" sandwich-style oil cooler/filter adapter. Why does my oil temperature rise when I am cruising at around 3500-4000 rpm? Around town and in traffic, even on a hot day such as today, the oil temperature runs right around 235-240° with the coolant temperature at around 200-210°. But if I run the engine at higher rpms the temperature starts to rise until I'm looking at 275° or more! The coolant temperature at this point is usually right around 210° which is fine considering. If the oil temp starts getting high, all I have to do is lower the rpm, or slow down, and the temperature returns to normal shortly thereafter. I cruised around today for a while and got it up to normal (240°) operating temperature, and then hosed the cooler down with cool water, and the oil temp started coming down immediately. This indicates that my oil cooler is installed and functioning properly, right? It has been suggested that I add a fan to the front of the cooler, but geez, I have it right out there in front of everything as it is. How much more air could I blow on it? The lines to and from the cooler are wrapped with Earl's Flameguard too. You can see pictures of the installation here. Thanks for any help in diagnosing this one.