Hi all.

Skoda superb 2.0 tdi LnK 155,000 mileage.2016 plate.

Car is loosing oil. Has been an ongoing issue.

1st mechanic I took it to said rocker cover gasket, so had that replaced. No difference.

2nd mechanic said oil gasket seal, so had the cambelt/water pump and oil gasket seal replaced. Car still loosing oil.

3rd mechanic pulled the oil dipstick whilst the engine was hot and running, saw smoke coming out of it and said pistons are going, and probably need a new engine as the car is burning oil inside the block.

Is this correct?

There are no visible oil stains on the driveway Or visible oil marks anywhere.

I have put oil dye in and checked with a uv light,but couldn't find anything.

Any suggestions on what to check besides a new engine.

Thats odd because mine has a similar issue and with similar miles as well. When my car was last at the official service dept they told me that the engine was very wet with oil and that they would have to book it in for further investigation as they were unable to pinpoint its origin. They said they would have wash the engine down, then spray it with white powder, take it for an extended drive and get up on the ramp and trace the leak back to its source as it would be visible in the powder.

Now just like yours, there is not a single drop of oil on the ground where I park outside the house, no signs of anything leaking on the ground, watter oil or anything. The car does not lack power at all, starts on the button, no visible smoke from the exhaust and there is no oil smell from the hot engine either.

I took the car to my indie garage for a MOT and also booked in with them for another date to look for the oil leak. They said that while they are doing the MOT, they would have a quick look at see if they could find any sign of the leak, and that would enable them to get the parts in ready for the following week to fit.

The car passed its MOT with flying colours and not a single advisory and they said that there was zero sign of an oil leak, the engine was clean as was the entire engine bay and all the under engine protection shield was clean and bone dry. Mechanic also said that if ever I was looking to sell it, he would like first offer on it and then cancelled the date made for the following week.

So, given that car had also just passed the MOT and also passed the emissions test with ease, where is my oil going? It is using 5 litres in approx 3,500 miles, that is slightly better than yours but it is way higher than what I'm used to so I'm guessing here that we do indeed have the same issue, so over you guys for your collective thoughts on what is happening here?

Edited 10 May, 20251 yr by Graham Butcher

Hi,

I admit this is way too high... Usual oil consumption on TDI engines is less than 1l per 15000km (this is my humble experience after 5 TDI engines from 2004)

However, I've often read that 1l per 1000km is still within VAG tolerances. 🙄 A good way for VAG not to pay for repairs when an engine starts overconsuming...

Considering the total oil capacity is 4.7l (incl. filter) on Superb Mk3 TDI engines, a complete oil renewal just by topping up, way before service or inspection (I never can remind which one is the smaller) due mileage should alert any VAG tech...

I cross the fingers for both of you, that's a quick and cheap fix.

@Bap33 I hear what you're saying and I agree it is too much, my other 4 superbs used to go for the full service interval with maybe half a litre of oil, but then, I had those from new and they were never thrashed and the last one I had for 10 years and it only had 78k on it when it was written off. But here's what I don't understand, neither @gidi19 or me, have any reports of smoke from the exhaust and I've had friends and family following me and nobody has seen any smoke from the car even when changing gears or slamming the pedal to the floor, and the car passes emission tests, so if the block was burning oil, where is the smoke?

The Vag TDI engines have had some issues with piston rings (at least on the Octavia version) which I guess is quite similar to the superb version.

As you have a DPF in a diesel you are unlikely to see smoke from the exhaust if it's burning oil as the DPF will catch it.

I would suggest to look for signs of oil just before the DPF or in the exhaust manifold somewhere.

Best case your engine is burning it and they'll be no problems.

But if there's too much oil to fully burn it'll build up in the DPF and can cause it to crack when it Regens...

I have a 2024 TDI 2l 200PS engine in my superb which uses 1L of oil every 7.5k km since new. (Currently at 37k km)

My previous Octavia TDI would do 30k km without changing the oil.

The title says 'Leak'

but if no oil is leaking it is actually about Using Oil. Different things.

Strictly correct, but in my case I was told by the Skoda repair centre that I had a leak and the indie shop said not, so not sure at the present time, hence the post requesting peoples thoughts on the matter.

Logic tells me that there is no leak externally as already mentioned both @gidi19 and myself are seeing any signs of oil on the ground, but could it be leaking into the exhaust, possibly via the turbo, but then surely the DPF would become blocked and the engine run lumpy and also the DPF light come on in the instrument cluster?

Edited 11 May, 20251 yr by Graham Butcher

If I had such oil consumption from burning and not leak or turbo, I would try piston soak. Won't harm and it's cheap. If the piston rings are stuck, that would unstuck them. Of course, if the oil rings are worn out, nothing could help, unfortunately.

My wife is driving the famous KIA/Hyundai oil burner 1.6 GDI engine, and at 160k km, it was burning 1L per 2000 km(~1200 miles). After the piston soak, it now burns 1L per 10k km(6-7000 miles). Yes, it still burns oil, but it's a great improvement.

What I would be very careful on a diesel is, how to unscrew the glow plugs since very often they've never been changed..

Surely if the piston rings are stuck, wouldn't that kind of suggest that the cars had not been used for a long period of time and maybe some corrosion had set in? Certainly is not the case with my car, it is use daily.

29 minutes ago, Graham Butcher said:

Surely if the piston rings are stuck, wouldn't that kind of suggest that the cars had not been used for a long period of time and maybe some corrosion had set in?

Nope, hers is used for daily work commute of 5-10 km.

Stuck rings are a side effect of the direct injection due to increased carbon deposits.

Often happening when the car is mainly used for short distances, gently driven and with long-life service intervals.

First two perfectly apply for my wife’s car, and even though I was changing the oil every 10k km, the oil consumption increased over time until it started to use more oil between oil changes than the amount used for the actual service.. 😅

There is official procedure which KIA/Hyundai have for such cases. I can share it, if someone is interested.

Edited 12 May, 20251 yr by fr1nklyn

48 minutes ago, fr1nklyn said:

Nope, hers is used for daily work commute of 5-10 km.

Stuck rings are a side effect of the direct injection due to increased carbon deposits.

Often happening when the car is mainly used for short distances, gently driven and with long-life service intervals.

First two perfectly apply for my wife’s car, and even though I was changing the oil every 10k km, the oil consumption increased over time until it started to use more oil between oil changes than the amount used for the actual service.. 😅

There is official procedure which KIA/Hyundai have for such cases. I can share it, if someone is interested.

Please do share it, I to tend to drive mine gently, not slow, but gently 😁

I have been driving in Eco mode taking advantage of coasting when ever possible, so went back to normal mode and engine braking was very noticeable, so it may be a worn turbo? I now have it booked for a diagnostic test on 4th June as I don't want the oil flow becoming so bad, if it is getting into the combustion chambers and let a runaway engine develop.

Here is the Hyundai/KIA TSB for excessive oil consumption, skip to page 4 https://static.nhtsa.gov/odi/tsbs/2021/MC-10205426-0001.pdf

I've also used the instructions in this video https://www.youtube.com/watch?v=bTEwZgXhzRs

As most of the folks having this issue recommend, I used the Berryman's B12 Chemtool and not the official Hyundai/KIA injector cleaner.

That's really quite a lot of work to get them out of having to replace the engine.

How often do you need to run the procedure?

4 hours ago, Gabbo said:

That's really quite a lot of work to get them out of having to replace the engine.

How often do you need to run the procedure?

How often, I don’t know. I guess it depends on the driving conditions.

On the petrol engine it takes 20-30 minutes to remove the plugs, add injector cleaner, rotate the engine and finally crank it without fuel pump fuze. You have to repeat it once or twice every 12 hours.

At the end you need to remove the remaining injector cleaner with oil pump or turkey baster.

It’s not a lot of work but it takes time. A weekend is enough.

Hi

Sorry all, I got busy over the weekend and just read the replies. Thank you all.

So as fr1nklyn suggested I am going to try a piston soak. I have already ordered the Berryman B12 and yesterday evening took the glow plug connectors off and squirted some wd40 into the glow plugs too loosen them up. Plan is to give it a 24 hour soak starting today after work.

I normally use quantum oil from TPS for the yearly service. Still leaking. I've also bought a 20 liter drum of Mannol 507 oil, just to keep topping the car up every time the oil low sign comes on. This time after the piston soak and a couple of engine flushes I plan on using Castrol 5w30 Edge, which was currently on offer at Costco for £30 for 5 litres. The thinking behind it being maybe a better quality of oil might help.

I also initially thought that it could be DPF related and had a DPF delete done. So technically the car doesn't have a DPF anymore so should not be doing any regens. (had it done at a reputable place for £450 so i'm assuming it was done properly)

I will do the soak over the weekend and reply back on Monday with any results.

The video I watched was for a soak on a 2.0 petrol engine where the B12 was poured into the piston chamber after removing the spark plugs. As mine is a TDi, i'm assuming the same procedure would be done but after removing the gow plugs? If anyone else has done a piston soak on a diesel I would be grateful to know how you did it.

On 13/05/2025 at 07:15, Graham Butcher said:

I have been driving in Eco mode taking advantage of coasting when ever possible, so went back to normal mode and engine braking was very noticeable, so it may be a worn turbo? I now have it booked for a diagnostic test on 4th June as I don't want the oil flow becoming so bad, if it is getting into the combustion chambers and let a runaway engine develop.

It was also suggested to me that can be a turbo issue, but the car drives completely fine. Please let me know how it goes for you.

46 minutes ago, gidi19 said:

It was also suggested to me that can be a turbo issue, but the car drives completely fine. Please let me know how it goes for you.

Will do, this morning I did notice that the engine sounded different when started from cold.

54 minutes ago, gidi19 said:

I also initially thought that it could be DPF related and had a DPF delete done. So technically the car doesn't have a DPF anymore so should not be doing any regens. (had it done at a reputable place for £450 so i'm assuming it was done properly)

Did you notice any sign of smoke from the tailpipe at all after the DPF delete?

4 hours ago, Graham Butcher said:

Did you notice any sign of smoke from the tailpipe at all after the DPF delete?

Car does not smoke at all.

Would have to double check in the morning.

I had someone follow me and they daid they couldn't see any smoke.

28 minutes ago, gidi19 said:

Car does not smoke at all.

Would have to double check in the morning.

I had someone follow me and they daid they couldn't see any smoke.

So that kinda suggests that either the DPF is still present and preventing any smoke from exiting it, or that oil is being burnt without any tell-tale smoke. Are you using proper oil or synthetic?

1 minute ago, Graham Butcher said:

So that kinda suggests that either the DPF is still present and preventing any smoke from exiting it, or that oil is being burnt without any tell-tale smoke. Are you using proper oil or synthetic?

Im using quantum 5w30. Im not sure if it was fully or semi synthetic.

The mannol one is fully synthetic and the castrol im going to put in doesnt say what it is.

Quick update.

Managed to take glow plug 1,2 and 4 off without any issue.

Glow plug 3 however is just spinning round and round. Im guessing its snapped. I was very careful and spray lots of wd40.

Im going to pour the b12 in the 3 plug holes.

Let it do its job and hope that glow plug 3 doesn't cause a major issue once its all back together again.

30 minutes ago, gidi19 said:

Quick update.

Managed to take glow plug 1,2 and 4 off without any issue.

Glow plug 3 however is just spinning round and round. Im guessing its snapped. I was very careful and spray lots of wd40.

Im going to pour the b12 in the 3 plug holes.

Let it do its job and hope that glow plug 3 doesn't cause a major issue once its all back together again.

Ignore above.

Glow plug 3 has come out successfully.

I was just being overly cautious. It needed turning alot more then the other glow plugs. I also kinda had to pull it towards me to get the threads to grip.

Just for anyone who wants to attempt it in the future. Here's a pic of joining got the b12 into the chamber.

I got a smaLloyds funnel and attached some clear plastic tubing at the end.

One thing to note,the area around the glow plugs was filthy. I should have sucked it all out but didn't.

Im going to try suck it all put somehow after the piston soaking