Overheating at Low Speed with Mishimoto E-Fans - Revert to OEM Clutch Fan

Coolingbeginner✓ OP Confirmed

Problem

After replacing the stock mechanical clutch fan with a Mishimoto dual electric fan kit (with aluminum shroud), the 7M-GTE overheats during low-speed driving, particularly on hill climbs. The car runs fine at highway speeds where ram air provides sufficient cooling, but temperature gauge skyrockets during sustained low-speed climbs (e.g., 60 km/h on steep twisty roads). The engine belly undercover was also not installed.

Temperature gauge skyrockets during low-speed hill climbsOverheating at in-town speeds (around 60 km/h) on steep roadsNo overheating at highway speeds or during full-throttle pullsElectric fans appear to move air with hood open but insufficient airflow under real operating conditions

Root Cause

The Mishimoto dual electric fans provide drastically insufficient airflow compared to the OEM clutch fan setup. Rated at only 2300 CFM (at zero static pressure), they deliver far less under real-world conditions where radiator backpressure is 10-15 mm-H2O. The OP confirmed they flow roughly 25% of what the stock setup provides. At low vehicle speeds where ram air is minimal, the fans cannot keep up with the cooling demands of the turbocharged 7M-GTE iron block engine.

Confidence

High confidence — Original poster confirmed this resolved the issue

View Original Thread →Posted July 2022 on SupraForums.com