After my car engine is heated up there is a distinct vibration or judder at idle speeds (when I increase the engine speed this goes away). One mechanic has suggested this may be the dual-mass flywheel and another thinks it may be the fuel injectors. The dual-mass flywheel is a mechanical part and I don’t see how this could cause vibration only when the motor is hot and not when it is cold. Could anyone shed some light on this?
You are correct. The mechanic who suggested this was the problem doesn’t understand the dual mass flywheel and so condems it for problems he cannot fix.
When the car is cold does the engine idle at a higher speed, preventing the vibration?
just a thought. have you checked your motor and tranny mounts? if one is bad it can cause a vibration.
My nonmechanic gut says the car is just plain running rough. The flywheel has as much to do with that as the phase of the Moon. If you’re going to listen to someone, make it the fuel injector guy.
What is the vehicle year, make and model?? Any codes present?
The car is a Ford Focus 1,8 litre diesel, built in 2008.
Just my 2 cents but I would make sure the compression is good seeing how this is an aged diesel with ? miles on it.
An injector could certainly cause a problem like this but so could a cylinder dropping pressure.
I also do not think this is a flywheel issue.
Testing injectors and compression on a diesel requires special tools with the former being a bit pricey. Odds are neither mechanic has either of those tools so having it done might require a diesel specialty shop.
Point behind a compression test is to make sure the engine is not dropping a cylinder. One does not want to throw parts/money at a failing motor.
Along with a compression check, do the valves need to be adjusted?