Hello,

I got a Check Oil Level warning the other day so I drove to the nearest petrol station, bought some oil and topped it up. Check Oil Level warning disappeared straight away so I thought everything was fine but when I got home I noticed an engine judder when I turned the car off.

Next day I drove maybe 10 miles to supermarket and other nearby places and every time I turned the car off I noticed the same judder, and also noticed the engine warning light had come on (may have been on since Check Oil Level warning, I am not sure). So at the end of the day I open the bonnet and discover to my horror that I had left the oil cap off after I had topped it up! Some oil had spewed out over nearby engine parts but nothing seems to have been damaged due to that.

However I am really worried by the engine warning light being constantly on now! Does anyone have any idea what might be happening? Have I ruined the engine by leaving the cap off?

It might help to know that the judder doesn’t happen when I turn off engine with clutch engaged. It could be that the judder was always there, and I only noticed now because I was more attentive due to Check Oil Level warning. At no point has the Oil Pressure warning appeared. I have put the cap back on and run it more a couple miles but engine warning light is still on. It’s a Fábia  Mk III if that makes any difference.

Thanks in advance for any help!

As long as it had sufficient oil remaining and there are no knocking sounds from the engine, it should be fine. Hopefully the judder stopped once you replaced the oil cap, its absence would have caused an uneven tickover.  Hopefully the EML light illuminated because the onboard diagnostics saw an imbalance caused by the missing oil cap and will extinguish or it needs a VCDS reset.

It will be OK, relax. 

Top up the oil again to compensate for what has spilled, 

With the cap off, the engine has a major 'false air' input that will have temporarily messed around with the engine control electronics' ability to regulate air/fuel mixture conditions. 

Hence the warning light and juddering. Once it 'relearns' normality with cap fitted properly all should return to normal including disappearance of warning light.

May take a few drive cycles.

I once checked my oil on my previous Octavia 1.9 TDI before setting off to Germany from York. Drove down via Dover, did 100mph+ on the Autobahn, and drove around a couple of days (total of about 800 miles later) and checked the oil again to discover I'd left the cap off!

 

Was a bit of oil splatter but it was fine. Bought a new cap from a local car place, topped up by a tiny bit and all was well.

 

The warning light and judder is due to the engine sucking in air where it shouldn't. So there is suddenl more air entering that hasn't come via the air flow sensor so the ECU is confused and puts a warning up.

Thanks very much for the replies! Ok I am more relaxed about it now. I’ve just driven it again, still warning light on but judder seems to be going away. Have booked it into garage on Monday but I’m less worried that I’ve wrecked my engine 😂

 

cheers! 

Engine warning light now gone! Thanks again for the replies, much appreciated 🙂

Yeah. Probably just needed some time to realise that everything was ok again.