Engine Temperature very slow on reaching temperature.

[c7w]

My Engine service light keeps coming on. The mechanic diagnosed the DPF being blocked, but most of my journeys are motorways. The second item that has come to our attention, is that the engine takes a long time to heat up, and the exhaust is low temp. The DPF was reset, but the fault continues.

The mechanic says that there is an auto vent on the radiator, that enables the engine to heat up quicker and this may have failed.

Advice please

 

 

[alanfp]

Does it eventually get up to a steady temp (needle pretty much in the middle of the gauge)? Or does it fluctuate and hover in the lower half of the gauge? If the latter, then faulty thermostat. 

I assume the mechanic means the auto louvres immediately in front of the rad. If they are like my Focus had, you can see them closed when you start the engine from cold. They rest in the open position when the car's electrics are off.

[c7w]

Hi Al

Thank you for your reply, 

Yes it reaches temperature and the needle is steady, Yes it is the auto louvres in front of the rad, the issue is they are stuck in the open position and the engine management flags this as an issue.  On a cold start up it takes to long to reach the desired operational temperature and it brings up the service light.

C7W