Weird... higher oil level

[Breezy_Pete]

Does the owner have maybe 0.5 litres of the oil unused?

If so, you could do a density comparison if you have some good weighing scales. If the used oil out of the engine is lighter than the same volume (at same temperature) of new, unused oil, that would be suspicious, I think.

[MTX]

The Skoda crankcase is vented through the lifter side and the oil from the head/valves goes the same pathway back into the crankcase. I would try a new membrane on the fuel pump, or change the pump just for a short time to see if its bad. The best oil for favorit/felicia engine is 10w40, the 5W40 is to thin for the construction of the engine. 0,5 liter of coolant would make emulsion in the oil. Fuel from the carburator would evaporate when the engine is hot and to get that amount in the crankcase some cylinder would have to be flodded and it would't start in the morning. My bet is on the fuel pump....

[KenONeill]

This makes no sense that I can see, particularly given that 5W-40 synthetic will be more stable and foam less than 10W-40 mineral (I think the cold viscosity is a bit of a red herring too, because this specific engine never sees 0C, more like 20C minimum?)

[RicardoM]

This makes no sense...

Of course it doesn't. Hence the word weird in the title of this topic.

[KenONeill]

Ricardo, bear with me.

 

Does the oil pressure on his car rise more slowly than you'd expect on a cold start? And more normally on a hot start? At this point note that I did once switch a car I owned from 10W-40 mineral to 0W-30 full synthetic, and was seeing faster oil pressure build up to the point where the warning light went off before the engine fired.

 

If so then the volume of "extra" fluid is about the typical capacity of an oil filter, so if the new filter has a failed (open) non-return valve or is a copy with no NRV, then it might add up.

[RicardoM]

Ken

Skoda Felicia has not an oil pressure indicator.

As for the oil filter hypothesis, I mentioned it 7 days ago then ruled it out.

Read above.

[KenONeill]

Ken

Skoda Felicia has not an oil pressure indicator.

As for the oil filter hypothesis, I mentioned it 7 days ago then ruled it out.

Read above.

Did you actually just say that a Felicia has neither an oil pressure warning light nor a gauge?

 

Also. by my reading (I re-read the whole thread before posting) you'd ruled out the filter bypass valve, which is a different thing to a non-return valve.

[RicardoM]

Did you actually just say that a Felicia has neither an oil pressure warning light nor a gauge?

 

Also. by my reading (I re-read the whole thread before posting) you'd ruled out the filter bypass valve, which is a different thing to a non-return valve.

Skoda Felicia has a low oil pressure warning light but has not an oil pressure gauge. Didn't you know that?? Furthermore, the warning light shuts off instantly during cranking. I hope you'll see why your lack of knowledge about specifics of Skoda Felicia made me tell you numerous times in the past that your generic, far fetched replies make more harm than good to people. But it seems you don't care. Trust me, I have a lot of grease on my hands from years of doing repairs on Skoda Felicia. Over 500 specific replies in this section stand proof to that. So let's forget about semantics on oil valves. Real auto mechanics is in a garage not in a Haynes library.

 

Bottom line is this: I have convinced the owner of the car that I don't have the means to analyze locally the used oil for contaminants, unless he is willing to send a sample to USA and pay $20 + shipping. I have showed him that people on this forum did their best to help and I thank them again for support. I will replace the oil and filter and ask the owner to monitor the oil level each morning for a month.

Edited 26 July, 2015 by RicardoM

[SaltySkoda]

Too bad we couldn't reason out the problem here.

Laboratory analysis is expensive, but there is one crude (but free) method anyone can try. See this page

It's about the so-called "business card test" used for testing the oil for contamination. Clean oil leaves an uniform blot on the paper, contaminated oil has a distinctive pattern (some examples here).

I do this on a weekly basis, a drop of oil from the dipstick and a piece of blotter paper is all you need.

[RicardoM]

Very interesting links. I will try it myself. Do you have more example photos for fuel contaminated oil?

[RicardoM]

Here is the test of engine oil in question on blotter paper (one drop left overnight to spread).

Anyone has an accurate interpretation? I couldn't find a similar looking sample photo.

 

[SaltySkoda]

Unfortunately I don't have any pictures of fuel contaminated oil to share with you. The blot you've posted looks fine.

The blotter paper acts as a filter for your oil drop. It tries to soak it in, leaving behind any deposits the oil may contain. That's what's left on the paper's surface. It seems that your oil is fairly fresh, because the central (black) spot isn't very large. So that's good.

Now, if the oil is diluted with fuel, it'll be less viscous. It would have the opposite effect of glycol, which thickens the oil and helps accumulate soot and other contaminants. If the oil lost its viscosity it will advance through the paper easily, i.e. it will soak in faster.

So you need a "control" sample of clean oil which will tell you the expected absorption time. You need to compare exact amounts of oil samples at exactly the same conditions (temperature, type of paper etc.)

As I said, this is a crude method and can lead to wrong conclusions, but the difference between clean and contaminated oil will be more obvious the more severe contamination is.

 

By the way, I also have a problem with "fuel cooking" in the summer because I couldn't fit an insulation plate between the carb and the manifold (I have a replacement Weber). It runs ridiculously rich on a hot start but it soon returns back to normal. I try to use the car only on long trips (at least 50 km) so the fuel could evaporate from the oil. But I'm also using thicker oil (15W-40), and it may help retain the fuel from passing by the pistons. So far I've had no issues with oil level going the wrong way.

Edited 31 July, 2015 by SaltySkoda

[RicardoM]

Thank you for advice, SaltySkoda. My concern is the outer thin ring (blueish, in fact transparent when viewed in light) that to me indicates gasoline...

 

Update: the owner of the car decided to do a thorough inspection of engine's health, just in case. That is before changing the oil, the filter, and the coolant. So now I am building a cylinder leakdown tester from local parts (a ready-made one is ridiculously expensive).

 

I am wondering how could I 'see' if the vaporization of fuel from carburetor's float chamber really occurs after stopping the engine. If only the carburetor was made of glass Anyways, the carburetor, the intake manifold, and the cylinder head are all hot. I don't see where gasoline vapors condensation could occur in such amount that liquid gasoline would pass an open intake valve then would seep around piston rings into the oil pan.

[KenONeill]

I'd suggest repeating the ring test with a drop of fresh 5W (was it 5W-30?) since one of its key points is that it is a light oil, and at 0C not much thicker than petrol. Obviously you won't get the central carbon disc, but it may give the same blue/clear edge ring. On the presumption that the used test was done at, say, 20C I'd expect petrol to vapourise.

[RicardoM]

Here is a drop of new engine oil on blotter paper (same brand, same type, car owner had almost half a liter left in a bottle).

 

 

Today I have looked closer on carburetor. I think that I've found something that might explain how fuel seeped down into intake manifold then past an intake valve and finally past piston rings.

 

Here is what I did. I took out the upper cover of the carburetor exposing the float chamber. I filled it with gasoline and let it sit for half an hour. To my surprise the float chamber was almost empty. I took out the carburetor and indeed the intake manifold was wet from gasoline.

 

 

The gasket of the so called part throttle enrichment valve was partially ruptured...

 

[Breezy_Pete]

Good work Ricardo.

The vacuum feed to that is from the base of the carb isn't it? So fuel was leaking straight down that vacuum drilling into the manifold.

 

My gut feeing looking at your first oil 'blot' was that the pinkish colouration made me think "petrol", but I, like you, couldn't find any similar photos online.

 

The car may start better and go better once you've replaced that gasket. Can you get hold of a refurb kit for that part in your location? It would be nice to change the outer gasket/diaphragm too, if you can.

[RicardoM]

Good work Ricardo.

The vacuum feed to that is from the base of the carb isn't it? So fuel was leaking straight down that vacuum drilling into the manifold.

Exactly. Now I can finally say I've found evidence for higher than normal oil level. Furthermore the owner of the car remembered that he had to pump the throttle pedal each morning when starting the engine. Obviously that is not normal. The engine should start without touching the throttle (well, after priming it 1-2 times to set the choke). He put it on fuel vaporization, but that happens only if the car sits in the sun for days.

 

I will replace the entire valve with a new one. It comes with a new gasket. I will replace the cardboard gasket between upper and lower bodies of the carb too. Luckily I had them both from my friend in Czech Republic.

 

The owner of the car went out for holidays and the car will stay in my garage for another 2 weeks. I will still do a cylinder leakdown test when he returns. I'll keep you posted.

[RicardoM]

I have finally managed to build my own cylinder leak down tester (CLDT) for under 50 USD.

I have tested the engine using 7 bar of compressed air. All cylinders passed the test having less than 10% leaks.

 

 

 

 

 

[D.FYLAKTOS]

On 16/07/2015 at 21:54, RicardoM said:

 

 

 

No "fresh air from the filter" from the left hose

only sends emissions into the throttle body.

[RicardoM]

On 13/06/2020 at 21:41, D.FYLAKTOS said:

 

No "fresh air from the filter" from the left hose

only sends emissions into the throttle body.

Totally wrong.

Not to mention there is no throttle body. It is a carburettor.

Edited 14 June, 2020 by RicardoM

[D.FYLAKTOS]

On 15/06/2020 at 00:26, RicardoM said:

Totally wrong.

 

 

So, the ''fresh air from the filter'' as you said helps where?

[RicardoM]

One month ago you suddenly felt the unneeded urge to reply to a 5 year old post without having a basic understanding of PCV.

I will not bother myself answering to your innuendo. You don't want to learn anything. You just want to stir trouble.