A week after the 1st service on my 1.4tdi last year I checked the oil and found that it was just under halfway up the hatched area on the dipstick. I was concerned as I assumed that the oil had been filled to maximum when it was changed and that there was a problem that had caused the consumption to increase. I filled up to the top of the hatched area and checked the level frequently. I needn't have worried as, apart from one small top up, it has used virtually no oil in 6500 miles.

This year I checked immediately after the service and found it was low again.I took it back to the dealer who topped it up. When I got home I rechecked it and topped up a bit more.I took the car for a run and then left the oil to settle for 20 mins. and it was exactly on the top line of the marked area. (rechecked today)

The technician said that he had filled with the recommended 4 litres. I know the oil level was in the safe area but I would expect it to be filled to the max. line not left at a level that I think needs topping up.(After driving a series of oil using commercial vehicles I am in the habit of keeping the level close to max.) Between us we must have added about a 1/2 litre - it sounds more when you say a pint.

I wondered if the recommended fill of 4 litres is insufficient to fill the filter as well, but I can't really believe that VW/Skoda haven't got their figures right.

Anyone else come across this? I've googled and can only come up with one other comment from someone on an Honest John forum.

I suspect they haven't allowed for the amount that goes into the oil filter, and maybe had filled it just short of the full mark anyway. After starting it fills the oil filter and they haven't topped it up so it shows up halfway down the hatched area. Either that or the calibration on the oil fill machine is incorrect and they haven't realised it. They set it to the amount of oil they want delivered into the engine and then just pull the trigger. It delivers...but the wrong amount in your case. I normally find mine overfilled a little after a service so I get my sucker machine on the go!!!

It is common practice on DPF equiped cars to only fill the oil to half way. This is because the DPF regeneration process is known to cause fuel dilution of the oil and hence increasing oil level.

Mark

Edited 21 April, 201115 yr by mark999

It is common practice on DPF equiped cars to only fill the oil to half way. This is because the DPF regeneration process is known to cause fuel dilution of the oil and hence increasing oil level.

Mark

Mark, from what I'm hearing from my tech colleagues, fuel dilution isn't that common, although it can happen under certain circumstances of course. Are you saying that manufacturers are now actively short changing their customers on oil for something that might happen but probably won't? If that's the case why did the garage top up Eastbournians oil? That would be a mistake if what you are saying is correct. I have several friends with the CR1.6 and none of them have experienced fuel dilution. One of them uses her car everyday but only does 90 miles a week. Her oil is always spot on when I've checked it. She has 4,000 miles on the clock now.

FOOTNOTE: Just noticed Eastbournians car is the 1.4TDI. Don't know if it has DPF but his sig doesn't say it's a Greenline. Even if it's a Greenline the PD engines are not noted for 'fuel dilution' as they only pump twice per cycle similar to my standard PD engine.

Edited 22 April, 201115 yr by Estate Man

Thanks for the replies Gents. I think you're right Estateman. The oil should been topped up after the engine had been run and the filter filled. The technician told me that he had filled it from a container not the bulk tank.

I don't have a DPF on my car but I think you raise an interesting point Mark999. We have to use a high spec. oil in PD engines to prevent wear in injector cams? (I'm no expert) operating at high pressure. I think that the only PDs with a DPF are the Greenlines. What would happen if the quality of their oil is diluted with fuel?

P.S. Wrote the above before I saw your last post Estateman. Maybe there's no problem with the Greenlines.

Edited 22 April, 201115 yr by Eastbournian

My Octavia was delivered with the oil level half way betweem min and max, I later questoned my dealer who stated that ther only filled them to this level.

A couple of months ago I had to remove approx 300ml of oil with my vacuum pump to drop the level below max and I'm close to having to again. A collegue who had a 1.6cr Fabia had the same problem.

Mark.

Hi Mark, I would seriously consider an oil change if it's fuel in the oil. Fuel dilution can have consequences if not dealt with properly. Dropping the level back down is not really the way to do it. You will still have fuel in the oil. I would also be seeking a professional opinion on whether it is actually fuel in the oil, and if so why? As a tech I worked on new cars that used to come in straight from the manufacturer with the oil level filled to half way up the stick. This was normal and most cars are delivered from the factory like that, even before DPF's came into being. It's the garage techs job to top off the oil to the correct level. Some garages just leave it as it is, not advisable in most peoples view on a new engine as most will use some oil during the first few thousand miles and owners are notorious for not checking the oil. But, fuel dilution is not a new problem. It has always existed, but is slightly more prevalent now with the DPF equipped cars. However, you should not be getting fuel dilution such as you describe unless you do a considerable amount of short journeys or drive very slowly not using the revs much. Or you may have an engine fault. It really isn't something that is or should be always happening, it is not very common. Incidentally, some people have confused fuel dilution with a build up of condensation in the oil which causes the oil level to rise in a similar way. This happens more in winter but can occur in summer too. A blocked or partially blocked engine breather can contribute to this, and is fairly common on diesels that don't do many miles especially in winter. The condensation causes a gunk that blocks the engine breather over time. This condensation in the oil happens on short journeys when the engine and or oil doesn't reach normal working temperature and be maintained at that temperature to evaporate the moisture. Don't forget that for every gallon of fuel burned (petrol or diesel) one gallon of water is produced, some of which always goes into the sump with the oil. It builds up in the oil if the car is not properly used on a hot run regularly.

Edited 23 April, 201115 yr by Estate Man

The older 75BHP 1.4TDI Polos have a oil capacity of 4.3 Litres. I have confirmed this over quite a few oil changes (6x). What is the later 80 BHP engine capacity as specified in the makers manual ?

The handbook for my 1.4tdi 80 bhp says 3.8 litres including filter change.

That's spot on Eastbournian...sorry for almost taking over your post earlier!

"Don't forget that for every gallon of fuel burned (petrol or diesel) one gallon of water is produced, some of which always goes into the sump with the oil. It builds up in the oil if the car is not properly used on a hot run regularly."

Surely that 1:1 ratio can't be correct.

"Don't forget that for every gallon of fuel burned (petrol or diesel) one gallon of water is produced, some of which always goes into the sump with the oil. It builds up in the oil if the car is not properly used on a hot run regularly."

Surely that 1:1 ratio can't be correct.

Fuel is a hydrocarbon with hydrogen atoms. It has no water in it but as we all know when you burn hydrogen in oxygen what do you get.....water vapour. Most of a cars exhaust is water vapour. I think he was suggesting that some of this gets past the rings and dilutes with the oil. Normally if the oil gets fully up to temp it just boils of the water. I remember my old Ford that loved to produce loads of that horrid mayonnaise type emulsion you get when this happens on a car with short journeys. We have all seen the large white cloud out the exhaust in winter, thats just the water vapour condensing.....or in the case of a Nissan Micra being driven by people of a certain age it glugs out the exhaust as liquid water as it pootles along at 20mph.

If any of that sounded patronising or teaching you to suck eggs I apologise.

Cant say any of my cars have increased the oil level because of water. I used to do lots of short journeys and only ever got the mayonnaise blocking my breather line. My 1.4TDI DPF Greenline never increases it oil level. Incidentally the garage on the two oil changes it has had filled to just below the max line.

1 gallon of fuel doesnt contain water, it contains the hydrogen that reacts with the air to create water so the statement he makes could very likely be correct.

"Don't forget that for every gallon of fuel burned (petrol or diesel) one gallon of water is produced, some of which always goes into the sump with the oil. It builds up in the oil if the car is not properly used on a hot run regularly."

Surely that 1:1 ratio can't be correct.

Hi Black...amazing isn't it and I understand your query, it's hard to believe. Raisbeck is correct in what he says. In the trade, during training we used to have to study this stuff so we could diagnose problems and properly understand an engine and fuel relationship. But yes it is roughly correct give or take a bit, allowing for winter or summer fuel. IIRC summer fuel gives just a bit more than a gallon of water due to slightly higher calorific value. Winter fuel slightly less. Although for analysis most measurements are taken in weight rather than volume. Each gallon of petrol produces approximately 8.3lbs of water. An imperial gallon of petrol weighs in at about 8lbs. I would point out petrol and water have differing weights per volume but not much. As Raisbeck says, there is no water in petrol or diesel, well there shouldn't be but there is actually because of the way it is stored, but not enough to interfere with the calculations...but the water is produced by chemical reactions between molecules. It's true most people are amazed at this revelation and wonder why it is important to know about this stuff. Here is why...

When an engine is started from cold considerable water content is created and is blown by the piston rings during the first few minutes of operation. this happens because the pistons and rings don't fit too well in the cylinder bores when the engine is cold. This 'blow by' contains unburned petrol and other hydro carbons as well as the other water content of course. On a two mile journey it was estimated about one quarter of a pint of water enters the oil during the first two miles of driving on the average modern petrol car. If the car is used only for very short journeys this water content remains in the oil causing 'oil rise'. It also turns to sulphuric acid within 3-4 days and starts to eat away at your engine parts. Your oil has neutralising agents in it to prevent damage but it gradually loses it's power as the mileage increase on that oil. This oil rise happens because the oil doesn't get hot enough for the oil to boil off the water content. So if you continually use your car for short journeys...also make sure you take it for a good run at least once a week to clean out the oil. It needs a very good long run to remove it if a substantial amount of water has built up.

Hope this doesn't sound patronising or as Raisbeck mentions, too teachy!

FOOTNOTE: Just found this interesting link for those of you that might like to take a look. Bear in mind it's an American site and measurements are US galls etc

My link What happens when I burn a gallon of gas? How much H2O (water is made)?, OXYGEN IS USED? etc etc. It's quite shocking to read!

Sorry Eastbournian...well off topic now!

Edited 24 April, 201115 yr by Estate Man

Hi Estateman. That's one of the things I like about this forum. It's often when posts go off topic that it gets most interesting and informative.

Hi Estateman. That's one of the things I like about this forum. It's often when posts go off topic that it gets most interesting and informative.

Hi Eastbournian, yes...I have to say that happens and as you say it can be interesting. Most of us find this site really useful and informative. I learned loads about Skoda and my Fabia on here. Over the last few years I've been mostly involved with motorcycle engine research and development on a very small part time scale. I also had another 'day' job away from that so have been away from the everyday car industry for a bit. This site brought me bang up to date again. We can all thank Colin D and his moderators for the way they conduct the site. They don't jump on us too much if going a bit off topic!

"Don't forget that for every gallon of fuel burned (petrol or diesel) one gallon of water is produced, some of which always goes into the sump with the oil. It builds up in the oil if the car is not properly used on a hot run regularly."

Surely that 1:1 ratio can't be correct.

This why you can see water dripping from some car's exhausts shortly after startup before the engine & exhaust have fully warmed up.

Edited 26 April, 201115 yr by vwcabriolet1971

Hi which oil is best for the 1.4tdi 70bhp?

Hi which oil is best for the 1.4tdi 70bhp?

Whats best is a matter for debate. Mine uses Castrol Edge 5-30. Meets all the VW specs regardless of DPF PD CR or whatever. I believe its also approved directly by Skoda also.

Whats best is a matter for debate. Mine uses Castrol Edge 5-30. Meets all the VW specs regardless of DPF PD CR or whatever. I believe its also approved directly by Skoda also.

Well it's Castrol I was plumbing for it's says shell helix in the engine bay but my crtdi has Castrol so I'll use same in both! Thanks