Thread: Smoking Habit (blow-by)

If you sit the cap back over the hole without screwing it down does the blowby blow the cap off, my rule of thumb is if the cap just sits there bobbling about it's ok, if it gets blown clear off the rocker cover, then I would worry. You didn't mention how many klms up, so it could be rings, do a compression test. Also get the radiator fluid checked for combustion gasses in case it's a head gasket on the way out, good luck, Regards Frank.

Originally Posted by Taz

Folks,

Is this excessive for a 300Tdi...

http://youtu.be/00o7w_OOSZ4

I recently noticed the oil trail from the oil filler cap running along the top of the cover down to the rear of the engine. Also what appeared to be tiny oil spray droplets on the top of the injector lines - oil seems to have been sprayed from the filler cap under pressure.

I normally have a a little oil leaking from around the rocker cover gasket, but leaking through the oil filler cap is new.

A few months ago I discovered a hole in my power steering lines (metal on metal contact wearing thru) and I gave the engine a few revs (no load) whilst trying to find the leak. It's hard to know how many revs I gave it as I had my head under the bonnet at the time. I'm wondering if I have broken a ring in the process. I guess head gasket is another possibility - I'm loosing a little coolant but I think that is due to the thermostat gasket (about to be replaced). There is certainly no pressure in the coolant system (yet?).

So is this amount of blowby excessive and a pointer to impending doom, or just another element of 'character' and the old girl should continue to solder on?

Thanks in adv,
Taz.

That looks like a textbook head gasket blow into the pushrod gallery to me, better get onto it before it pressurises the crankcase enough to run on its own oil

JC

Thanks Gents,

Filler cap resting in place does a little dance but doesnt bounce off. Nevertheless, following Justins advice and that the blow-by was never this bad until recently(engine rebuilt 240,000km ago) together with the slight coolant consumption - time for new head gasket.

Thanks again,
Taz.

Could it also be caused by the engine breather filter being blocked?

I remember a while ago someone else had a blocked one and it pressurised things up.

I'm with "nice1guv", check your crankcase breather filter and the line returning to the air intake trunking, I reckon it's better to start looking there you may save yourself a lot of dramas, not to mention work. So unless you have noticed a big drop off in performance you can safely say the head joint is ok, most IC engines have a bit of fuming when they get on in life a bit, but if crankcase breathing systems are working ok they will "soldier on" without bleeding to death.
It seems to start and idle ok, it sounds like a Tdi, hope for the best.