Good day everyone, 

 

 

As per the title, today I noticed my BBZ 2007 Fabia sort of puffs blue smoke during road trips, when hot and after a few hours of continuous use, only after coasting. It only happens after long sections of downhill coasting with zero throttle input, but as soon as the throttle is applied after the fact, *puff*, blue smoke. The appearance of smoke is sporadic, the car doesn't smoke at idle, nor under load most of the time, only after engine braking has been used for long periods. Oil was changed two weeks ago, and even if oil consumption has been noticeable since I got the car (5 years ago) the smoke issue is new. Oil is Shell Helix Ultra if that matters, compliant with VW 502.00 specification. I change oils every 7500 km. The car has 141.000ish km now. 

 

I wonder if it's just a case of replacing valve stem seals (about time anyway) or it could be something more serious.

 

About the fuel leak issue, it just popped up in the past two days. After a trip with my family to the countryside, we noticed a strong fuel smell in the cabin. I went to check the pump under the back, lo and behold, there's fuel pooled inside the top of the fuel pump and to the sides. Testing the pump in-situ didn't yield any obvious results, there aren't any apparent faults while pumping, so it looks like the fuel leaks while the car is moving, as it sloshes around or something. Is it common with these fuel delivery units to leak at the top? Fuel lines seem intact and everything is tight. The whole pump assembly was replaced two years ago for a genuine unit.

 

As always, I appreciate your input on these issues. 

 

TIA.

 

 

 

Is that white pipe fractured?....

 

16 minutes ago, TMB said:

Is that white pipe fractured?....

 

Not that I could feel. That's just a bit of paint flake.

OK. I presume you've checked that the big plastic retaining ring is tight? If so, you might have to remove the pump and check the rubber seal.

9 minutes ago, TMB said:

OK. I presume you've checked that the big plastic retaining ring is tight? If so, you might have to remove the pump and check the rubber seal.

Yes, I've checked it and it's quite tight. You're correct, rubber seal is next, plus a general inspection on the pump. Otherwise I'll have to drop the tank and filler neck I guess.

The oil smoke is the valve stem seals allowing oil to be sucked down worn valve guides when cylinder vacuum is high during closed throttle conditions.

8 hours ago, juanse_2691 said:

I wonder if it's just a case of replacing valve stem seals (about time anyway)

Like @sepulchrave I'm pretty sure this is oil being sucked past the inlet valve stem oil seals on overrun.

Thanks everyone, I'll get the car checked and fixed as soon as possible.

Turns out I was wrong.

 

 

The pump gasket was indeed knackered, but it isn't the source of the leak. The pump inlets look healthy, so I guess the clips securing the lines to the pump itself are faulty. Since I have no means of dropping the tank or testing the lines or the clips to rule them out, I'll have to take the car to a shop and solve that problem.

Fuel leak solved. A very small crack in the return inlet was responsible for the pooling of fuel over the pump. A bit of epoxy resin did the trick, as I'm not in the mood for shelling out (again) the near £300 they are asking for a new genuine pump where I live.

 

 

 

Replaced the valve stem seals, I think after 15 years and 150000 km it was fair to exchange them. Also solved various oil drips and leaks around the engine block and crankcase cover/oil pan.

 

But the new stem seals didn't do much to stop the blue smoke after coasting. Oil consumption seems to have diminished a little, though.

Edited 16 February, 20224 yr by juanse_2691