307 2.0 hdi 136 turbo low pressure - fixed

Post by **tmead** » 20 Mar 2017, 18:05

Just thought I'd share my joy at having found the cause of this.

The car has a reasonably serious oil leak, marking its territory like a big cat whenever it is parked for a few minutes. Or maybe more like a rat, continually dribbling, but lets not go there.

I took a good hard look all round the flywheel end of the engine on Saturday morning, including removing the airbox, battery tray and starter motor. Everything is dry above the gearbox, so its not the HP pump seal on the end of the camshaft. Everything was cleaned and wiped up as best I could before a run out. Car was dramatically down on power, very flat as if the turbo wasn't kicking in. No error messages for around 30 miles, then the useless 'antipollution fault'. Mpg pretty much as normal, car starts and drives fine, just down on power

At home, PP2000 showed only one message related, which was turbo low pressure fault. All manner of things go through my mind - turbo failure, vacuum valve failure, injectors issues (there is a clacking noise when warm).

I went through checking all the hoses were in place and secure, nothing seemed wrong. Only by chance I touched a small vac pipe down over the top of the starter under the air doser, and it was flapping in the breeze. plugged that back in by feel (cant see) and everything is right again ! Just goes to show - the vaccum circuit is so critically important, but leaks are very badly detected on Pugs and Cits. (Previous C5 had a split rubber elbow in the vac line and reported the turbo as failed).

The motto is - always check the vac pipes, and don't jump to hideous conclusions about the most disastrous failure possible !

Oh yes, the oil leak sadly must be the crank seal, which was changed around 12-15K ago with the clutch - proper PSA part too ! That will need doing again soon, but will need to wait for a weekend with a good forecast. I'll put a sleeve on the shaft to, it didn't look scored, but the last one was starting to leak and it hasn't taken long for this one.

Tim