Temperature Gauge Wandering and Dashboard Gurgling - Radiator, Thermostat, and Coolant Flush

Coolingintermediate✓ OP Confirmed

Problem

Temperature gauge would warm up beyond the halfway mark and fluctuate up and down several notches, never settling at the normal Toyota 4 o'clock position. Dashboard had a gurgling/waterfall sound indicating trapped air in the cooling system.

Temperature gauge wandering above midpoint, not settling at normal 4 o'clock positionDashboard gurgling/waterfall sound from heater core areaLack of confidence in cooling system for sustained high-load driving (long highway grades)

Root Cause

Combination of a degraded original radiator with internal deposits, a cheap low-quality aftermarket thermostat (from Pep Boys), and contaminated coolant system causing poor heat transfer and air pockets in the cooling system.

Confidence

High confidence — Original poster confirmed this resolved the issue

View Original Thread →Posted May 2020 on SupraForums.com