Peugeot 508 2013 – 1.6 e-HDi Automatic

[AhmetGk]

**Peugeot 508 2013 – 1.6 e-HDi Automatic

Engine Does Not Reach 90°C / Low Operating Temperature – Thermostat Replaced, Issue Persists**

Hello everyone,

I have a 2013 Peugeot 508 1.6 e-HDi automatic and I’m experiencing a persistent low engine operating temperature issue. I would like to explain the situation in detail to get informed opinions.

Work Already Done

Complete thermostat housing replaced

Thermostat was purchased from an authorized dealer using VIN

The new thermostat housing came with a pre-installed ECT (engine coolant temperature) sensor, so the sensor is also new

No coolant loss

No overheating

Radiator fan never activates

Problem Description (Clear Observations)

Even with ventilation completely OFF, the engine does not reach 90°C

During normal driving, temperature stays around 80–85°C

In stop-and-go traffic or at idle, temperature drops further

On highway driving (80–100 km/h):

Radiator fan does not turn on

Temperature stabilizes around ~80°C

Even in summer, engine rarely reaches 90°C

Ventilation / A/C Clarification (Important)

A/C is OFF (compressor not engaged)

Only the blower fan / ventilation is used

Despite this:

Engine temperature drops at low speed or idle

Cabin heating is not very hot

When ventilation is OFF, airflow from vents feels cold

Fan and Thermostat Behavior

Radiator fan never comes on

Coolant hoses are warm; mechanic states the thermostat is “open”

However, the engine fails to warm up properly

Fan inactivity suggests the ECU does not see high coolant temperature

Ruled-Out Causes

Water pump failure (no overheating, circulation present)

Head gasket or blocked coolant passages (no coolant loss, no pressure issues)

A/C compressor load (A/C OFF)

Suspected Causes

Even though the ECT sensor is new, the ECU may be reading coolant temperature lower than actual

Possible ECT wiring, connector, or engine ground issue

ECU strategy may be:

Opening thermostat early

Never commanding the cooling fan

Keeping engine in 80–85°C range

There are no fault codes or warning lights.

My Questions

Is 80–85°C normal operating temperature for the 1.6 e-HDi, especially in winter?

Has anyone experienced this behavior even after thermostat replacement?

Can ECT wiring / connector / ground issues cause this without triggering a fault code?

Is it normal that the radiator fan never activates in this scenario?

Any technical insight or similar experiences would be greatly appreciated.

Thank you.

[PaulC5]

Are you reading the temperature with a code reader and live data or just from a gauge on the dash ?

[Mihael_M]

The thermostat on that engine should open at 83 C, and the temperature should be around that before a little below. If you connect an ELM327 cheap reader, you can monitor the temperature with your mobile phone. If everything is fine, then the temperature does not go up to 90 C.