As to the Oil expansion as your 'table'.

If you have 4 litres there just put it in a pan, test the temp using a cooking thermometer or any device you like, then heat to 90*0c or the 100*oC and see how the level has risen.

I have done that.

Size, depth, surface area, capacity obviously makes a difference how noticeable a rise in the level is.

Dipstick tubes and dipsticks are not like watching a pipe level in an experiment heating liquids.

 

I have also fried chips and battered mars bars or pizza crunchies often enough and observed the oil in the pan and the difference out of the bottle 

and then when ready to start frying.

 

If you want to check the actual temp of the oil in the sump when dipping, then a 43 pence Digital Thermometer is as good as anything, 

and is actually good for checking the indicated oil temp the car is showing and the actual oil temp.

Edited 24 October, 20187 yr by Offski

Stage one of data collection went to plan, with support from Staropramen to aid my patience...

 

Spoiler/executive summary:-  (on this engine) it makes very little difference whether you measure the up-to-temp oil level 10 seconds after switch off or 25 minutes after (max level difference 1.5mm). If you wait 4 minutes, you'll be within 1mm of the reading you'd get if you waited for 6-25 minutes.

Graph and raw data to follow tomorrow, with a cold level to compare to as long as I remember in the morning. (Setting reminder alarm now). 

 

This is with Quantum Platinum 5W40 oil - very recently changed - in a BBY-code 1.4/16V engine, so not bang up to date tech, but not fundamentally different really from a lot of today's small petrol engines. Aluminium alloy sump. Plastic sumps may well have a higher expansivity coefficient though.

 

If any other VCDS owners would like to add to this data, that would be awesome.  I can start a thread to pool results, somewhere or other on the forum.

Module 17-Instruments, I logged MVBs 3, 7, and 1. Won't be very successful unless your car has an oil level/temp sensor in the sump, obviously.

 

Edited 24 October, 20187 yr by Wino

Only on the Briskoda forum can we take something so simple as dipping a sump (in which the difference between min and max level is probably 20% of the total volume) and make it sound like we need lab conditions to be able to check the oil. 

 

Good effort @Wino looking forward to seeing the rest of the data.

 

 

 

 Bet he forgets to check in the morning....

Well I didn't forget, but I wasn't as thorough this morning so I'll probably have to repeat it tomorrow.

 

At first glance, the oil level was 0.5mm higher than at its highest reading yesterday/warm, but that dropped on the very second 'read' to the same as yesterday's peak reading, and carried on falling over the ~3 minutes I logged for this morning.  Difference today was that I didn't support the battery voltage with an external supply. Whether that laziness on my part explains the drooping reading I don't know, but if I repeat that bit of the experiment tomorrow and try it with the external supply I may know more then.

 

Raw data for both logging sessions here Oil level 25Oct18.CSV, along with a lightly annotated plot of yesterday's data only below. The vertical blue line near the start of the plot is engine shutdown. I'd let it idle a while after getting home (only 5 miles) and then raised the revs for a while until the fans kicked in, then started logging.

 

The quantum of reported oil level is 0.5mm, and it does a lot of jumping about between reported levels, but my impression of the 'warm' data is that the level had peaked and was just starting to drop back from 'more 55.5mm than 55.0mm' to more 55.0mm than 55.5mm at the end of my session.

 

With my external power supply on the battery yesterday, set at 12.7V, initially no current was drawn, but over the 25 minutes that gradually went up to about 1.4A by the end.

 

 

 

Edited 25 October, 20187 yr by Wino

There must be a joke here, somewhere along the lines of how many forum members does it take to check the oil level?

@xman can you think of any other explanation for the descending reading this morning, unrelated to a drooping battery voltage?  Data right at the end of the linked spreadsheet.

I would've thought the level/temp sensor would be designed to work reliably independently of supply voltage within reason, but never had occasion to test that before.

 

This is normal. Boys and toys. 

 

Don't be dipsticks.

I think you will find that is why you have a min and max. Keep somewhere between the lines and you'll be ok, keep above and/or  below by more than a small degree, then you will be in risk territory! Remember, the oil not only lubricates but also helps maintain steady heat transference. It cools the engine, along with the coolant of course. So too little will allow the engine to overheat somewhat and this will thin the oil even more and perhaps hinder the lubricating process. 

 

I think the short interval in this instance will not have a great effect overall and it was spotted and rectified but also noted so any issue SHOULD be rectified by Skoda anyway as they are aware of their fault. As for the brake discs, if this photo was accurate of the whole of both front and real of both discs, I think the dealer was "Advising" you of something that was perfectly typical of motoring applications. He may have been covering his own back, whilst fishing for work. I had a few tyres replaced yesterday and the fitter verbally mentioned my brakes being worn. I said I spotted that and they were around half way there but that still leaves half, perhaps less as you don't want metal to metal contact! I also stated I do those myself and they are quite simple to which he agreed. So, no work from me changing pads and discs that I can change myself at the CORRECT interval but had they have been well worn, he would be neglectful to NOT mention things!

There is the 'Zabozuma'  check i do on TSI engines with the Oil Filter on top of the engine.

 

I open the car and pop the bonnet.  Dip the oil and see the cold level.

Put the key in and start the engine and stop it right away, only runs for seconds.  Then i dip the Oil.

The Oil pump had the oil up to the filter and the head. 

Shut the bonnet.

 

When done a good 10 miles or so or when i get where i am going i dip the oil after a few minutes.

Surprise surprise the level when hot shows the same as having started and stopped the engine. 

    Simple enough to try and see with ones own car or any car, see there is enough oil before setting off or if you need to put some in or go buy some.

 

For some cars it was important, they could use 1/3 of the oil capacity with just 1 tank of petrol and no warning lights or message.

http://briskoda.net/forums/topic/288698-oil-usage-in-fabia-vrs

 

Edited 25 October, 20187 yr by Offski

13 minutes ago, Wino said:

@xman can you think of any other explanation for the descending reading this morning, unrelated to a drooping battery voltage?  Data right at the end of the linked spreadsheet.

 

I know it's early in the morning, but my attempt at a joke was aimed at the whole thread and not you, Wino.

 

Just now, xman said:

 

I know it's early in the morning, but my attempt at a joke was aimed at the whole thread and not you, Wino.

 

No, I wasn't complaining about your joke when I asked that question, it was a genuine appeal to your expertise, unrelated to your post.

Read this  J00137_Oelniveausensoren_GB_TT_korr1.pdf

Page 10 ultrasonic oil level sensor

 

It made my brain hurt.

35 minutes ago, Wino said:

@xman can you think of any other explanation for the descending reading this morning, unrelated to a drooping battery voltage?  Data right at the end of the linked spreadsheet.

I would've thought the level/temp sensor would be designed to work reliably independently of supply voltage within reason, but never had occasion to test that before.

 

 

Is your power supply man enough to power the car without the battery? The ability to adjust the voltage would show us how sensitive the sensor is to voltage changes.

 

Do you know the principle of operation  of the sensor, as an instrument tech i'm intrigued to know. At a guess it seems it may be a capacitance probe of some kind.

Thanks xman, but I don't think it's exactly that one in my sump, mines this type: https://www.ebay.co.uk/sch/i.html?_from=R40&_trksid=p2380057.m570.l1311.R1.TR1.TRC0.A0.H0.X1J0+907+660+C.TRS0&_nkw=1j0907660c&_sacat=0

 

I did just find a photo of the innards that I seem to have done some work on a while back, and it looks like everything on the PCB is  powered off a regulated supply, so ought to be immune, but there might be +12V connections to stuff via tracks on the other side which I can't see from that pic. Also, I'm not sure what's on the other end of the via hole at the left end of the inductor that says 100J (upside down) on the right of image.

It's making my brain hurt now.

 

Edited 25 October, 20187 yr by Wino

2 minutes ago, SuperbTWM said:

 

Is your power supply man enough to power the car without the battery? The ability to adjust the voltage would show us how sensitive the sensor is to voltage changes.

 

Do you know the principle of operation  of the sensor, as an instrument tech i'm intrigued to know. At a guess it seems it may be a capacitance probe of some kind.

 

Good call, and yes, at 5A max output I should think it would do the job.

I believe it's an ultrasonic sensor, but how it works in physical principles has eluded me so far. There are two prongs like a tuning fork, but joined at the top, and each has a buried - inner layer - serpentine track going up and down the length  of the fork:

 

How do those buried tracks make ultrasonic vibrations? Maybe it isn't ultrasonic?

Better (but still poor) pic of the tracks (commoned at the middle pin):

 

Edited 25 October, 20187 yr by Wino

Well I haven't got a clue either really. In my world ultrasonic sensors sit above a tank or vessel and use the ultrasonic waves to calculate the distance between the sensor and the fluid giving a level or volume depending on the parameters you put into them.

 

This looks like a completely different beast, but very impressive for such a small device.

My brain is still hurting.

 

How did we get from dipsticks to this?

6 minutes ago, xman said:

My brain is still hurting.

 

How did we get from dipsticks to this?

 

 I wondered if it might be a cleaner, more reliable way of reading oil level, for those with level sensor and VCDS. The jury is still out.

 

Actually, the main point was to investigate the effect of cold/hot dipping and timing of hot dipping. Seems like on my car, it makes very little difference when you dip/measure the oil level; IFF we believe what the sensor tells us...

Edited 25 October, 20187 yr by Wino

Looking at that PDF it looks like the ultrasonic emitter may be in the base of the sensor and then the long part is the receiver, I don't think ultrasonic waves can transition from air into fluid or fluid to air so i presume this is how the level is worked out

Simplest way to know the difference between cold and hot dips.

 

Dip the oil before setting off or starting the engine.

When you get back home or where ever park in the same place and dip the oil before leaving to go where you are going.

?

What difference is the level on the dipstick.   Maybe rather different with an engine with 2.8 litre capacity and one with 4.6 litre.

The cross hatch area will not be 1 litre difference with a 2.8 litre oil capacity engine.

7 minutes ago, Offski said:

The cross hatch area will not be 1 litre difference with a 2.8 litre oil capacity engine.

 

It may well be because the x-y dimensions of the sump will tend to scale with engine size.

^^^ 

Again simple to see about 'may well be',  anyone with a engine with 2.8 litre oil capacity can check.    It is all 'Simply Clever really'.

 

Those with a 1.2 44 kw that read the Owners Manual might see they are told to check them cold.

Edited 25 October, 20187 yr by Offski

6 minutes ago, Offski said:

It is all 'Simply Clever really'.

 

Well instead of providing endlessly repeated comments about what exact state/time of engine warmth to dip the engine in, why not provide dipstick measured data about how much difference it makes, on each engine type you know about?

And you keep telling us about your heating oil in a pan experiment, and recently you confirmed you'd actually done it, but you don't tell us what the pan was made of, what heat source was used, what diameter the pan was, or even what the level difference was when you tried it. Vagueness just doesn't explain anything.

Edited 25 October, 20187 yr by Wino