Review on Derale 18217 17-inch High Output Radiator Fan in Black by Dmitriy Kingsley

Installed on Chevy Blazer with SB 350 engine. This is a two speed, very high RPM fan. Fan with thinner protection on the radiator side. I removed the original metal fan and installed it as a direct replacement. Wired to a low speed so it turns on as soon as the engine starts (e.g. when the engine fan starts spinning as soon as the engine starts). Connect the high speed to the 190(on)/180(off) thermal switch mounted on the intake manifold. Uses two separate relays for each speed. Rarely shifts to high speed even when hiking in the desert.