#thermostat
6 posts in Car Diagnostics blog about "thermostat" — OBD-II diagnostics, DTC codes, repair. ← All posts
-
Temperature gauge going up and down: thermostat or air lock
A needle that will not settle is telling you coolant flow is intermittent. Whether that is a lazy thermostat, trapped air or a failing pump is decided by when it happens.
-
The thermostat: two ways to fail and two very different consequences
Stuck open, a thermostat never lets the engine warm; stuck closed, it destroys it. The signs of each and what diagnostics shows.
-
Heater blowing cold: seven causes in order of cost — from free to expensive
In winter this is not a comfort question but a visibility one — a fogged, iced windscreen. The causes in ascending order of cost, and a ten-minute check through live data.
-
Preparing a car for winter: what to check over OBD and what by hand
Winter does not break cars — it exposes what was already broken. A weak battery, slow warm-up, and a small vacuum leak are invisible in summer and become a morning call-out in the cold.
-
Coolant Leak Diagnosis: OBD-II Detection Before Overheating
How to detect coolant leaks through OBD-II: P0128 thermostat, P0116 ECT sensor, P0217 overheat — step-by-step diagnosis and causes. Catch it before engine damage.
-
P0128: why the engine won't warm up — thermostat, sensor or something sneakier
Deep dive into P0128: when it appears, why thermostats fail stuck open, how to diagnose without teardown, and why a "cold" engine burns 10-15% more fuel.