I did a 40,000 mile service on my Octavia (90 bhp TDI) over the weekend, but I've just got a couple of questions.

Firstly, having changed the fuel filter (using the 2 new o rings), the Haynes manual says to check that there aren't bubbles in the clear pipe when the car's idling. There are bubbles, even after taking it for a drive. Haynes make no mention of what to do if there are bubbles.... Wobbling the pipes, etc, on the filter whilst it's running makes no difference. I remember when the car was pretty new, there was always a fairly big bubble at the top of the clear pipe with the engine off, and when I mentioned that to the dealer at the time they said it was fine, so I'm wondering if it's always had bubbles and it's maybe nothing to do with the new filter... Should I worry, and if so what should I do?

Also, I started the engine after the oil & filter change & it was fine. I started if after the fuel filter change and it started instantly (I pre-filled the new filter). I think I maybe started it once more without problems, but then the next time I started it (to check something else) it took a little while to fire. The final time I tried to start it (a couple of days later) to drive it out of the garage, it took quite a while to start... I was beginning to worry that I'd broken something, but having run it upto temperature yesterday night, it started perfectly this morning. I think I remember it being slightly slow to start once before after I'd started it a couple of times just to move it a few feet. Has anyone else noticed that? And, if it is normal, just out of interest does anyone know what actually causes it?

Thanks for reading all that!!!

Alan

are we talking petrol or diesel here??

if it isn't starting first flick of the key i would suggest checking you have attached the hose in the right places, there should be a static holding pressure in the fuel supply line even when the ignition is off, and when you put the key in it should prime itself anyway..

Sorry - diesel - can't believe I forgot to say that!

90 bhp TDI, and I'm pretty sure the hoses are in the correct places.

Thanks,

Alan

did you remove the hoses from the control valve??

or did you lift out the control valve from the top of the canister??

is the o ring on the bottom of the valve seated properly??

is the split pin that holds the valve down securely fitted in place??

the best way to purge the air from the system is to blip the throttle loads of times then let it return to idle each time

did you remove the hoses from the control valve??

or did you lift out the control valve from the top of the canister??

Lifted the valve from the canister

is the o ring on the bottom of the valve seated properly??

The new o rings were correctly seated on the control valve before I inserted it into the canister. It's hard to be sure what happened when I pushed it into place, though. Could they have come adrift?

is the split pin that holds the valve down securely fitted in place??

Yes, the split pin's in correctly.

the best way to purge the air from the system is to blip the throttle loads of times then let it return to idle each time

I've done that 3 or 4 times, with no change, and taken it for a short drive on the road.

I think the car's always had a bubble in that pipe when the engine's not running (but I've never checked before with it running - really wish I had now!), so I'm not convinced that it hasn't always been like this... Still doesn't seem right though...

try putting a little bit of vaslene over the fuel hoses where they come into the filter houseing.

Any air ingress means the fuel will leak back to tank overnight etc.

Just to update you, I started off putting vaseline on the hose joints under the engine cover (as I was about to put the cover back on, and I think there had always been an air bubble when the engine wasn't running, so I wasn't convinced it was the filter joints).

Put the cover back on, then had to go out - first time I'd used it since my previous posts. When I got back there were no bubbles at idle. So, either it was fine all along and just needed a longer run, or it was a joint nearer the pump. Either way thanks for your help!!! And now, as long as vaseline doesn't do anything bad to the fuel pipes, it should be sorted for the next 4 years at least!

Thanks again,

Alan.

PS I think the slow starting must just have been a result of several start, idle for a few seconds, stop, as it's been perfect since. No idea why that would affect it though...

they copper greased mine at the main dealers.