Thread: Tdi Engine Fumes / Bypass??

Originally Posted by sumo

G/Day all, My 130 Tdi is showing signs of excessive bypass on idle'

If you take the oil filler cap off on idle it wants to blow you away, Give a few revs, and i mean just a few!!, and there is no bypass at all

The oil consumption is pretty good over a 6000k interval.. 500ml.


The motor has done about 219000ks sounds ok, little bit rattley around the big ends on very cold start up, but not overley concerned about that yet. Its just this fumming thing on idle, is this normal with the 300 motors.??, Makes them look like they leak oil

Cheers Sumo

Harmonics. The internal engine space on a 5 cyl is not constant so you are feeling piston pulses at idle. Under load at revs is what counts so yours sounds fine.

A difficult thing to quantify, some have a little more than others but at 200K I would be concerned that yes it does have a little too much clearance in the cylinders or glazed bores if it has had a life of no load and lots of idling. I have seen 550K engines with minimal blowby, and 100K engines with heaps. I have even seen one that was overpressurising enough to leak out the front and rear crank seals, the crankcase vent into the turbo inlet pipe was dripping in oil aswell.

Dusting an engine will cause this too, in a very quick period of time...

One of The reasons the blowby disappears when you rev slightly as the low pressure of the intake air rushing into the turbo draws the fumes into the turbocharger, circulating them through the intake system aswell.

To test the theory, disconnect the intake vent pipe from the intake hose near the turbo inlet, leave the filler cap on and see how much pressure there is. Now remove the filler cap also and see how much there is.

If it keeps on pushing it out then yes, it is excessive.

Also there is a slim chance of a head gasket leak into the pushrod galleries between 3 and 4 cylinders, but this will be chronic, even under revs. There will also be a severe popping type of noise from in the rocker cover.


As just mentioned by others though, some will go forever with symptoms like this, not getting any worse or using oil etc, so don't be too worried yet.

JC

219 is bugger all. Mine has 310 and no spanners yet. Burns no oil but yeh a bit rattley. Dont worry, its fine for years and years...