DS4 2011 take too long to heat up

[Manchinga_]

Hi guys, I don't know if it's just me or if really takes that long to heat up this model. I was checking the coolant temperatures with my OBD and it takes almost 20 min to reach 100° any one else is having problems to have heating during winter? I'll attach a graphic of that so you can see it. Also after 10 min running when it get to 90° it opens up and drop the temperature down to 75° after that looks working fine

[PaulC5]

Is it a diesel or petrol engine, which one and is it just the same in warmer weather ? Diesels being more efficient can take longer to warm up. It could be the thermostat needs replacing, it should not open until about 90°C but if the radiator top hose starts to get warm before this then consider replacing it.

If not the thermostat and it is not blowing warm air into the cabin then possibilities can include the heater matrix being blocked, the heater warm air flap not moving.

[Manchinga_]

It is a petrol engine 1.6 VTi, not sure during warmer weather, never tried it. I'll take a look in the hose to see if it opens up a bit before it should

[PaulC5]

We had a 2010 C3 1.4 vti petrol with manual air con controls and the warm air flap cable from the rotary knob kept getting bent and not moving the flap. A new cable did not help and in the end it needed a new heater as the flap was seizing up and not moving to the warm position. This was around 10 years ago and cost around £1k at the dealer to replace.

[Mihael_M]

The thermostat opens at a lower temperature, it needs to open at 102 to 105 C. But after that it works fine. I would leave it because it often happens that new thermostats work the same way.
Now its working temperature is good, but if later the working temperature decreases and the engine never reaches 100 C, then the thermostat needs to be replaced.

[PaulC5]

A quick search does suggest the 1.6 vti thermostat should start to open at 105°C so something odd looks to be happening at 90°C that has dropped the temperature. Is this when the cabin heater blower was turned on ?