⚠️ With the weather getting colder we are starting to see lots of vehicles with faulty thermostats causing no end of issues with DPF lights coming on, increased levels of black smoke and poor MPG.
❄️ Vehicles running cold due to lazy/sticking/stuck thermostats won’t trigger engine codes so simple diagnostic code reads won’t identify the issue. You need to know what to look for and how to test them.
❗ If coolant temperatures are too cold then DPF regeneration will be delayed. Ironically driving fast in cold weather actually cools the radiator down further the faster you drive so thrashing it up and down the motorway trying to get it to regenerate is counter productive.
If you see temperatures dropping on the dashboard as you drive then get your thermostat checked. As well as affecting DPF regeneration, cold running engines won’t be efficient causing a drop in fuel economy, a rise in emissions and as a consequence much faster rate of carbon buildup causing poor running.
We took a call from one of our regular customers – a Transit of theirs had the DPF warning appear and then limp mode issues. After some guidance and checks over the phone we identified the thermostat the likely culprit.
This was changed yesterday morning and once done the DPF started regenerating again.
After continued driving here’s the feedback on MPG…
💬 ‘Hi Adrian, just another update, MPG has gone from a bad average of 24-26 to 33.8 👍🏻👍🏻‘
👨🔧 A thermostat check is just one of the health checks we perform on your vehicle at every Which? Trusted Traders approved Engine Carbon Clean booking.
See more examples here…