PID 05°C
Coolant temperature
Coolant temperature.
What is normal
After warm-up it holds 85–105 °C. Wandering — look at the thermostat.
These figures hold for most cars, but the maker has the last word: some engines run hotter or idle higher by design.
Codes about this parameter
P0117Engine coolant temperature circuit low inputP0118Engine coolant temperature circuit high inputP0128Coolant thermostat — temperature below regulating temperature
We have a detailed piece on thisGeely over OBD-II: what answers and what stays silent
Step by stepHow to tell whether the thermostat is to blame
Codes behind this reading
If the value is out of range, the unit usually says so with one of these codes.
P0116Engine coolant temperature circuit range/performanceP0117Engine coolant temperature circuit low inputP0118Engine coolant temperature circuit high inputP0128Coolant thermostat — temperature below regulating temperature
How it feels behind the wheel
The same fault shows itself in different ways. Each sign below says what to look at in the live data.
It stalls while drivingThe engine dies while the car is moving — at speed, in a corner or when lifting off. The steering and brakes go heavy at once.Hard to start when hotIt starts instantly from cold, but after a drive it cranks for a long time and catches reluctantly. Pressing the throttle sometimes helps.The temperature gauge is climbingThe needle goes above its usual place, there is a hot smell from under the bonnet, and the heater may blow cold on a hot engine.Knocking under loadUnder acceleration or on a hill the engine makes a metallic rattle, as if small change were being shaken. It goes away at steady throttle.The heater blows coldThe engine is warm but the heater blows cool or barely warm air. Sometimes one side is warmer than the other; sometimes it only gets warm while driving.The air conditioning will not come onThe button presses, the light comes on, but there is no cold air. Sometimes the compressor clutch does not click when switched on; sometimes the cold disappears only in heat or in traffic.Idle speed huntsThe tachometer needle wanders up and down with the car standing still: 1200, then 600. Sometimes the engine nearly stalls and picks up again.Fuel consumption has gone upYou refuel noticeably more often for the same driving. The lamp is usually off — the unit thinks it is coping.It cranks but will not startThe starter turns the engine over briskly, but it does not catch. Sometimes it catches and dies.Slow to warm up, the heater blows coldThe temperature needle sits low for ages, the cabin stays cold, and on the motorway it gets worse. Consumption rises noticeably.Smoke from the exhaustVisible smoke from the tailpipe. The colour is the clue: white, blue and black mean entirely different things.The cooling fan runs all the timeThe fan roars right after starting and does not stop even on a cold engine or in frost.
How to see it
In CarScan: the Live data tab, «Start polling». The app asks the car several times per second, draws a graph and remembers the highest and lowest value of the trip.