Hi

I posted a topic a few weeks back because I was having problem with the "control system for exhaust" light coming on, on my 1.2 petrol fabia 1

My story last time was that this light came on (shortly after having a service). I checked all my levels to find that my oil had been overfilled during service. A local garage drained out an excess of 1.5litres and turned the fault light off for me. It came back on after 50 miles.

I have had the fault code read 3 times now, and it has been something different each time. First time (when i had the excess oil removed) it was 02 sensor, second time MAP sensor, and third time the mechanic said that loads of sensors came up so it could be any. Each time they turn it off it comes on again after about 40-50 miles.

I am unsure what to do next. The garage said the cheapest option to begin with is for them to clean the 02 sensor and see how it goes; so I have it booked in for this saturday but I feel unsure that this is the right thing to do, they have quoted me £45 +vat, and it may not solve the problem.

Would the over-filling of oil at my service have caused this fault problem? The local garage said that too much oil can damage sensors, and therefore I may need to get one or more replaced; but because it comes up with a different fault code each time they dont know which one may need replacing.

More recently I have noticed a smell, the smell only happens for about half a minute, it smells like a dustbin lorry. My boyfriend said it could be the catylic converter?

I just have no idea what to do next, if all of this stuff is connected, please help!

Who overfilled it by that much? If it was a professional, surely it's up to them to fix each and every resulting problem, entirely at their cost. What engine code is it? I think if it's like the slightly older 1.2s it's meant to have less than 3 litres of oil, so 1.5L of overfill is a very big margin of error.

If it was an amateur, that's unfortunate.

Who overfilled it by that much? If it was a professional, surely it's up to them to fix each and every resulting problem, entirely at their cost. What engine code is it? I think if it's like the slightly older 1.2s it's meant to have less than 3 litres of oil, so 1.5L of overfill is a very big margin of error.

If it was an amateur, that's unfortunate.

It was a professional who did the service, and I have contacted them about the issue but unfortunately this garage is 5 hours away and I only used it because my service was due at the time I was visiting family. I was therefore planning on sending them a letter soon as I get it all sorted, with a full summary of all the costs I have incured

Although all of this started straight after the service I dont know if the problem (whatever that actually is) it is a result of the overfill of oil or not...

Overfilling by 1 litre above the maximum mark would definitely help cause issues with sensors of the type you describe, as well as potentially damage the very expensive catalytic converter. Look under the bonnet and you will see the dire warning on the oil cap. Can you get the garage that drained the oil to write a letter saying it was overfilled? If the garage that overfilled is otherwise unwilling to help, you could try threaten small claims court action against them.

I must admit I find the VW style dipsticks difficult to read, as they always seem to get oil on above the bit with the markers on, presumably from the sides of the dipstick tube. I now just look for a dry bit at the top of the segment with markers on.

Edited 20 February, 201313 yr by anewman

Overfilling by 1 litre above the maximum mark would definitely help cause issues with sensors of the type you describe, as well as potentially damage the very expensive catalytic converter. Look under the bonnet and you will see the dire warning on the oil cap. Can you get the garage that drained the oil to write a letter saying it was overfilled? If the garage that overfilled is otherwise unwilling to help, you could try threaten small claims court action against them.

I must admit I find the VW style dipsticks difficult to read, as they always seem to get oil on above the bit with the markers on, presumably from the sides of the dipstick tube. I now just look for a dry bit at the top of the segment with markers on.

I will definately be doing everything I can to get my money back once it is all sorted, but for now I need to find out what is going on

I think the problems must have been caused by the overfill- its too much of a coincidence especially as you say it can damage the catylic converter. If a mechanic was to inspect this part, would he know if it is damaged?

It would be interesting to know which sensors could have been damaged by the oil overfill, does anyone know if there is something like a sensor map I can look at, does that even exist?!

Many thanks for your replies!

if the O2 sensor is covered in oil when its removed, then the chances are the CAT will be full of oil. The overfilled oil and excess crankcase pressure this will cause has to go somewhere, and will find any means of escape it can. So via combustion chamber, piston rings, oil seals etc. Overfilling by 50% is very bad indeed, especially given how far the garage must be from you to be many hours away. Chances are that considering 1.5 litres were removed it was overfilled by a lot more.

if the O2 sensor is covered in oil when its removed, then the chances are the CAT will be full of oil. The overfilled oil and excess crankcase pressure this will cause has to go somewhere, and will find any means of escape it can. So via combustion chamber, piston rings, oil seals etc. Overfilling by 50% is very bad indeed, especially given how far the garage must be from you to be many hours away. Chances are that considering 1.5 litres were removed it was overfilled by a lot more.

Good point that.

If it's the same set up as our 1.2, once the O2 sensor is removed (assuming it's the primary, pre-cat one they're thinking of cleaning), a bright torch shone down the manifold hole it comes out of gives a limited, but decent view of the cat honeycomb. Ask your local garage to assess the state of the cat while the O2 sensor is out, in this way.

MAP sensor also may be contaminated, as its location in the inlet manifold will have been subjected to a hell of a lot of oil mist, I'd suggest. Visual inspection (two screws to remove) advised.

thanks so much for your helpful replies!

Worryingly I had done over 1000 miles before discovering the oil overfill, as I didnt think to check the level initially (didnt think i'd have to, having just had a major service!)

My car is booked in to a garage on saturday so I will ask them to check the catylic converter once the 02 sensor is removed. And i'll ask them to inspect the MAP sensor too

I'm guessing the combustion chamber, piston rings, oil seals etc could all be damaged too, then...

thanks so much for your helpful replies!

Worryingly I had done over 1000 miles before discovering the oil overfill, as I didnt think to check the level initially (didnt think i'd have to, having just had a major service!)

My car is booked in to a garage on saturday so I will ask them to check the catylic converter once the 02 sensor is removed. And i'll ask them to inspect the MAP sensor too

I'm guessing the combustion chamber, piston rings, oil seals etc could all be damaged too, then...

Wait and see, but no point in being unduly pessimistic. Is the car leaking any oil onto your driveway?

Wait and see, but no point in being unduly pessimistic. Is the car leaking any oil onto your driveway?

no, no spillage.

Before the excess oil was removed I had an intermittant burning smell, though.

Now i'm left with the "bin" smell

Any news?

took it to the garage on saturday, they were unable to remove the o2 sensor, said it had fused into place and that if they forced it they would ruin the threads and need to replace the whole unit. so anything is yet to be done!

They said they'd like my car for a whole afternoon, but they dont have a courtesy car for another 2 weeks, in 3 weeks time I am visiting family again near the garage who originally caused the problem so I may as well just go back to them!

Do you think I am in my rights to get them to pay for the diagnostic I had to get at a different garage?