My 120k 90bhp 1.6TDCI has recently developed a noise I'd describe best as similar to noisy tappets though I can't be sure. I've been getting a diesel exhaust smell in the cabin though uncertain if related - gather this is likely related to the leaky injector on no4 though no3 showing similar to a lesser extent. I've posted a video here, any suggestions? TIA, Dave

 

leaking injectors have a pool of diesel cooking nicely in the heat around the injector which smells inside the car   and/or    have the chuffing sound.

My fiesta 1.6tdci did this on a few occasions as each one leaked at a different time. Each time one started leaking I did the two retaining bolts up tighter and this cured it.

My brother now has the car and one has started leaking again which i previously tightened. Bit I reckon it lasted at least 25k miles before leaking again.

You must not overtighten , it you strip thread or snap the stud you will have MAJOR problems sorting it out.

they are special nuts which need a hex bit putting inside the top of them.  When mine were leaking they were not very tight , I put a hex bit in the end of a screwdriver type handle and could do them up tighter with my hand on the handle (no T bar or anything) so that shows they were not tight at all. I think mine started leaking at about 80k-100k miles.

I did not have to remove any pipes etc but I had to undo the two bolts holding the injector wiring loom to move it sideways a bit