Failed MOT on Emissions Ford Focus 1.6 diesel (2014 – 53,808 miles)
Reason for booking in…
‘Hi my car has just failed it’s mot on emissions, do you have any advice that could aid this?’
Ford Focus 1.6 Diesel Engine Mount Wear and the MOT Emissions Fail
Initial inspection found an engine wobble and a significant amount of rumble and shake from the carbon present.
The owner was typically doing short trips and using cheap fuel which had got the engine in this condition. The engine was struggling against the carbon buildup and this meant the engine mounts were degraded.
Initial code read found some unrelated historic codes spread across the vehicle that we documented and cleared for the owner.
Live data all showed injector fuelling was acceptable, coolant temperature values fine, etc.
On with the clean and it soon smoothed out, quietened down and by the end it was quiet, smooth and responsive again. The owner can now take it for retest, look to get the engine mounts inspected and replaced and switch to better fuel.
Why Engine Mount Wear Causes an MOT Emissions Fail
This is a textbook case of Ford Focus 1.6 diesel engine mount wear building slowly until it was enough to fail an MOT emissions test. Engine mounts do more than hold the engine in place, they absorb vibration so the engine runs smoothly and burns fuel efficiently. Months of short trips and low-grade fuel let carbon build up until the engine was working harder than it should, and that extra strain wore the mounts down further. A worn mount lets the engine rock and vibrate under load, which disrupts combustion and pushes emissions levels up.
Under the DVSA’s MOT inspection manual, an engine mounting that’s severely damaged or deteriorated enough to cause excessive movement is a Major fault, and one that’s fractured, missing or excessively loose is Dangerous. The carbon clean addressed the underlying build-up so the engine ran smoothly again, and the owner was advised to get the engine mounts inspected and replaced separately ahead of retest. For this vehicle, Ford Focus 1.6 diesel engine mount wear was the root cause behind the failed test, not a fault with the DPF or emissions system itself.
Frequently Asked Questions About Ford Focus 1.6 Diesel Engine Mount Wear
Can worn engine mounts cause a car to fail its MOT on emissions?
Yes. Worn engine mounts let the engine vibrate and move more than it should under load, and that extra movement can disrupt combustion enough to push emissions levels over the MOT limit.
What are the signs of engine mount wear on a diesel car?
Common signs are a noticeable engine wobble, extra vibration through the cabin, rumbling at idle, and clunking noises when pulling away or changing gear.
Does an engine carbon clean fix worn engine mounts?
No, a carbon clean removes the build-up causing the engine to run rough, but it does not repair the mounts themselves. Worn mounts still need inspecting and replacing separately.
How often should a Ford Focus 1.6 diesel have an engine carbon clean?
Most owners return roughly every 15,000 to 20,000 miles, depending on driving style, journey length and fuel quality, with a clean just before a service or MOT being ideal timing.
