What happens when you take the oil filler cap off a 1.4 16v Fabia?

[2638tim]

Hello,

I have a 1.4 16v Auto (BBY engined) Fabia. It has suffered from a thirst for oil since I got it about 2 years ago (4 litres every 5000 miles or so. I've read about the crankcase breather hose issue and checked this and all looks ok (i.e. no gunk and certainly not bocked). In fact I ran the engine at idle without the hose connected to the air box as I thought it might be blowing air... it was actually producing a reasonable amount of suction... Is this normal? This did give me a error which I read with vag-com - 17912 Intake Air System: Leak Detected P1504 - 35-10 - - - Intermittent

I'd read that removing the oil filler cap sometimes you might hear a slight hiss if it was the crankcase breather. I did this with the engine idling and this is where it got interesting... with the car idling, removing the oil filler cap made the car nearly stall---> recover ----> over rev----> nearly stall and then over rev... and would have repeated until the engine popped out of the bonnet I'm sure. This also created the following vag-com errors...

17961 - Barometric / Manifold Pressure Signals: Implausible Correlation P1553 - 35-10 - - - Intermittent

01166 - Engine Torque Signal 03-10 - No Signal - Intermittent

01166 - Engine Torque Signal 16-10 - Signal Outside Specifications - Intermittent

01314 - Engine Control Module 79-10 - Please Check Fault Codes - Intermittent

All of which seems excessive as a result of removing the filler cap! However, I could quite easily believe this could be normal given the complexity of modern engines. I search the forums and the web and can't find anyone else (stupid) enough to have tried taking the oil filler cap off while idling. Has anyone else come across this?

Anyone got any ideas what to check next to solve the oil consumption issue? EGR valve, recirculation pipe and throttle body are on the list but slightly worried it's the piston seals as normally (i.e. oil filler cap located where it should be!) the car runs great (i.e. no lumpy idle, responsive accelerator, smooth running etc)?

[seboni121]

Is that a petrol or diesel? You shouldn't remove the filler cap as the engine is under stress to drive the oil around, by opening the cap you are breaking the vacuum, never heard of anyone deliberately opening when engine is in idle ?

[gadgetman]

Not to mention risking hot oil splashing on you and the engine bay.

[Chadruharazzeb]

What a lunatic!!

[GeneralPurpose]

Tim, all the errors you list are normal if you remove the oil filler cap or the engine breather hose. Suggest you don't do it again though. It interferes with the engines tightly controlled emissions system and plays havoc with all the sensors around the intake and exhaust area. That's why you get the errors you mention. Those errors will now be stored in the ECU KAM (keep alive memory) so you may need to explain this if you visit the workshop techs and they do a diagnostic as they may actually think you have had or have a fault.

As for the oil consumption...I think it is a bit heavy but actually may well be within tolerance for this engine. I don't have the figures on what it should use but it can be quite a lot before it's regarded as being faulty or worn. How many miles has the car covered? What oil are you using? You may also want to try a different oil perhaps but one approved by VW/Skoda. For example, if you are using a 0-40 synthetic oil, switch to a 5-40 oil. This will make quite a difference to oil consumption usually.

One other thing. Depending on your mileage covered it is very unlikely your piston rings are worn. More likely is worn or damaged valve stem oil seals. These can let quite a lot of oil into the combustion process and account for high oil consumption. However, these are normally quite easy to replace with minimal engine strip down and they don't cost much. Come back with the info requested above.

Edited 28 September, 2011 by Estate Man

[barrheadred]

if the valve steam oil seals (or any fault causing burning oil) are away there would be blue smoke coming out exhaust,you said you've had it 2 years ? is that from new ? if so dought piston rings or valve steam seals are worn.

but yeah,dont take oil cap of when running !!!

[2638tim]

Thanks for all the replies!

It's a petrol automatic 1.4 16v BBY engined 2003 Fabia with just over 55000 miles on the clock. I'm using Castrol EDGE 5W-30 which is on the list of VW 504 00 spec oils.

It doesn't smoke at all and passed it's MOT emissions test ok.

I'll give the thicker oil a go next time I top up to see if this stems the flow (thanks Estate Man).

At least when someone else is thinking of taking the oil cap off they will know what happens! So... don't take the oil cap off when running and risk hot oil splashing on you and the engine bay - lunatic!!

[barrheadred]

I'm guessing you've obv checked for no external oil leak ??? no mention of this in you're first post

i.e sump gasket,rocker cover gasket etc etc

[2638tim]

I'm guessing you've obv checked for no external oil leak ??? no mention of this in you're first post

i.e sump gasket,rocker cover gasket etc etc

Yes - checked all that and it's clean.

[GeneralPurpose]

Tim, It may just be that the engine was run in with the foot hard down from new (usually results in more oil usage later on in the engine's life), or it was run in too slowly at low revs, low speeds etc etc (always results in more oil usage later on in the engines life). But again, don't worry about it unless it sound mechanically very very noisy. Switching to a 5w-40 oil will certainly make a difference, but not sure by how much. Can't think there is anything wrong with your engine if it passed emissions ok. It's just an oil user, and some are so, again, I would not worry too much about it, just check it regularly and top up when required. Good luck mon amie!

[fabdavrav]

Thanks for all the replies!

It's a petrol automatic 1.4 16v BBY engined 2003 Fabia with just over 55000 miles on the clock. I'm using Castrol EDGE 5W-30 which is on the list of VW 504 00 spec oils.

It doesn't smoke at all and passed it's MOT emissions test ok.

I'll give the thicker oil a go next time I top up to see if this stems the flow (thanks Estate Man).

At least when someone else is thinking of taking the oil cap off they will know what happens! So... don't take the oil cap off when running and risk hot oil splashing on you and the engine bay - lunatic!!

I have the earlier AUB engine and run Mobil 1 0W-40 spec oil no probs......5W-40 min......no way would I run on a 5W-30 spec!!!....Also they do need long hot runs and use the rev range please! And use Shell Vpower in them as they require 98ron petrol. When you do the next oil change do an engine flush using Wynns to get rid of all the old oil/varnish etc and fit a new oil filter as well!!

P.S. please remember to post in the MKI Fabia section next time!!

[rum4mo]

I have the earlier AUB engine and run Mobil 1 0W-40 spec oil no probs......5W-40 min......no way would I run on a 5W-30 spec!!!....Also they do need long hot runs and use the rev range please! And use Shell Vpower in them as they require 98ron petrol. When you do the next oil change do an engine flush using Wynns to get rid of all the old oil/varnish etc and fit a new oil filter as well!!

P.S. please remember to post in the MKI Fabia section next time!!

Fabdavrav, you are talking about the older higher output engines there, the BBY is a later kind of sorted out engine, but it only has 75PS output and will not be able to make good use of 97 or 98 RON fuel - as its engine map was written for the lower octane fuels. Both my VWs use what I would call "too much" oil, but maybe that is VAG engine designs for you, better a bit of oil useage than heavy wear.

[fabdavrav]

Fabdavrav, you are talking about the older higher output engines there, the BBY is a later kind of sorted out engine, but it only has 75PS output and will not be able to make good use of 97 or 98 RON fuel - as its engine map was written for the lower octane fuels. Both my VWs use what I would call "too much" oil, but maybe that is VAG engine designs for you, better a bit of oil useage than heavy wear.

Sorry...forgot that the OP has the Auto...which has the 75bhp version of my engine tunned for the autobox. :S

[TeflonTom]

What a load of old cobblers on this thread,

The 16v engines are well kown for eating their own piston rings then drinking their own oil, they do tend to breath out pretty heavy through the crankcase breather too, try replacing the breather pod on the back of the engine block and cleaning out the rubber hose that comes from the pod to the air filter housing. By your description you must have pretty high crankcase pressure for it to suddenly falter when you release the oil cap..

Whilst you are in there it's worth cleaning the inside of the airbox too, it will be caked in oil.. The other thing to be careful of on the 16v engines is that you don't overfill the oil, I get hideous oil surge on mine when it's over full, on hard cornering oil gets sucked up through the breather pipe and burnt in e engine in spectacular fashion

Don't worry about the fault codes, you don't even need to bother clearing them, intermittent codes automatically get erased after 50 starts of the engine if the fault doesn't reoccur.

Edit, oh and don't undo the bolts that hold the rocker cover on that engine in a vain hope of checking the gasket, you will cause yourself a whole world of ball-ache if you do, there is no gasket in there as it uses a sealant.