Temperature Gauge Reading High - Wrong Thermostat Rating and Bent Valve

Coolingbeginner✓ OP Confirmed

Problem

Temperature gauge reading higher than its normal position (slightly below center) during driving, particularly noticeable with AC running in hot weather. The issue was progressively worsening beyond what was typical in previous summers.

Temperature gauge reading above its normal slightly-below-center positionHigher than normal temps especially noticeable with AC on in hot weatherCondition worsening over time compared to previous years

Root Cause

The aftermarket Motorad thermostat installed ~10 years prior was the wrong temperature rating (82°C/180°F instead of the OEM-spec 88°C/190°F) and had developed a bent valve that was likely sticking intermittently. While it still opened at its rated temperature when bench-tested in boiling water, the bent valve caused unreliable operation in the car.

Confidence

High confidence — Original poster confirmed this resolved the issue

View Original Thread →Posted June 2024 on SupraForums.com