2.0 TDI 150 excessive blowby?

[pcspinheiro]

Me again...

So, my car has never needed any oil top up between services, but recently I got the low oil warning light and had to add over 0.5L to bring it to the top mark on the dipstick... I know some oil consumption is OK/normal, and a call to the dealership told me that for the amount of Km travelled since the last service it was within range. Fine. But I checked a couple of weeks later and it seemed to be lower again... I also had the coolant level drop to below minimum in the reservoir around the same time, was topped up at the dealership but seems to be down a little again. In the previous years of ownership it also never needed a coolant top up... 

I'm very hypochondriac when it comes to my cars, so today I started it and remembered this simple test for excessive blowby that I saw being done on old mercedes W123, which is basically to unscrew the oil filler cap and see if it dances around with the pressure or if it stays put. Well, mine was dancing violently and on the verge of being blown away, and there was quite a lot of smokey air coming out of there. Sadly I didn't remember filming it, but I  can do it some other time. Is this a bona fide indication of excessive blowby? If so, how should I approach the stealership about it? The head mechanic there is a fu****g wizard, he guesses that nothing is wrong without even looking at the possible causes and dismisses any of my suggestions immediately... For example, my car keeps pulling to the right after they aligned it, and it gets worse under throttle load (as he himself observed). When I suggested some play/wear on suspension bushes, causing the arm fall back under load, he immediately dismissed this without even looking at the car... This is what I have to deal with here: him and the lady at the reception that cannot stop herself from rolling her eyes right to my face when I complain about things, even when they are sooo obvious.

 

Any input?

[pcspinheiro]

Ok, got home and took a video with a hit engine. Now, I'm only a DIYer that learns things from forums like this, service manuals and, obviously, YouTube, but this seems like an awful lot of blow by...

 

https://photos.app.goo.gl/HTCT8iZqDHJ67Rpi9

[ApertureS]

You say it needed 0.5L, youve not said how long over? When was it last serviced? And who serviced it? Was it ever at the maximum? 

 

If it was serviced at a dealer its only ever filled to the half way mark.

[pcspinheiro]

Always at the dealer, yes. I can't say how many Kms it did since the service but I could find out, and I know how many it had when it asked for oil. Still, it never consumed any oil between services before... Maybe it is within spec, but specs seem like an unrealistic figure, right? I mean, manufacturers often say that 0.5l/1000km is normal 😒

What worries me is this enormous pressure coming out of the oil filler opening... 

[Ootohere]

The owners manuals for all VW Group engines says that May use as much as 0.5 litre in 1,000 km / 621 miles, under certain conditions.

 

They have for over a decade.  That does not mean 0.5 litres in 1,000 km is acceptable.   0.3 litres in 1,000 km might not be if you are not towing an elephant over a high Alpine pass in high summer. 

 

So you need to do an accurate Oil Consumption test. & then there are official oil consumption tests where the new oil is weighed after being dropped and then the km / miles driven and then dropped and weighed.

........................

But unlike this muppet doing it, 1 litre is not 1,000 grams.  it is 857 grams. @ 15*oC.

(The owner got a new engine.  Because the official test was crap as was the report.)

Edited 2 June, 2022 by roottoot

[Ootohere]

This is how it used to be done.

*5,000 km not miles, by the VW Group bumf on the example of an owners manual at the bottom.*

Edited 2 June, 2022 by roottoot

[ApertureS]

1 hour ago, pcspinheiro said:

Always at the dealer, yes. I can't say how many Kms it did since the service but I could find out, and I know how many it had when it asked for oil. Still, it never consumed any oil between services before... Maybe it is within spec, but specs seem like an unrealistic figure, right? I mean, manufacturers often say that 0.5l/1000km is normal 😒

What worries me is this enormous pressure coming out of the oil filler opening... 

Engines always have pressure in the crank case, thats why the crank ventilation is there.

 

Youll need to tell us when it was last serviced and how many miles it has done since or we wont be able to work anything out.

 

The dealer only ever fills a car to half way on the dipstick. This means your car has lost 0.5L if its dropped to the minimum mark, if youre saying youve only added 0.5L to bring it to the maximum mark then that makes sense and doesnt indicate a loss, the reason for the warning light im not 100% on and may have a faulty level sensor, but if youve added 0.5L to bring it to the max, then it would of never been below the minimum.

[J.R.]

11 minutes ago, ApertureS said:

Engines always have pressure in the crank case, thats why the crank ventilation is there

 

Or not there (blocked) in this case judging by the video.

[pcspinheiro]

36 minutes ago, ApertureS said:

Engines always have pressure in the crank case, thats why the crank ventilation is there.

 

Youll need to tell us when it was last serviced and how many miles it has done since or we wont be able to work anything out.

 

The dealer only ever fills a car to half way on the dipstick. This means your car has lost 0.5L if its dropped to the minimum mark, if youre saying youve only added 0.5L to bring it to the maximum mark then that makes sense and doesnt indicate a loss, the reason for the warning light im not 100% on and may have a faulty level sensor, but if youve added 0.5L to bring it to the max, then it would of never been below the minimum.

I'm not sure anymore it went to max level when I topped it up.... When the oil warning light came on the oil wasn't touching the dipstick at all, IIRC. I checked the bottle and I actually added about 600 mL. It's almost down to the minimum mark again in under 5k km, so while the oil consumption may not be excessive it's definitely, possibly, maybe there.... I think I drove about 12.000 km from the last service until it asked for oil. Car is now clocking 74k km.  

 

Regarding the blow by, to me it looks excessive, you can see the oil cap wanting to jump off and a lot of smoke. If anyone else that owns a 2.0 TDI superb would be kind enough to to the same simple teste to see if it's a thing or not, I'd really appreciate it. 

 

One thing's for sure, my 21 yo, almost 400k km petrol Opel Astra has a LOT less blowby as tested like this. I'd say nothing comparable even. Car runs like s clock still, always starts right away. My superb has, on occasions, krancked the engine quite a lot to get it to start, and then does it a little "violently". What got me worried was this mechanic specialized in old mercedes, that said that this test was a simple way to see if the Merc was in need of an engine overhaul due to worn piston rings. Why would a modern, relatively new car with - I reckon - much smaller tolerances, have so much pressure coming out of the engine top? Doesn't this seem off, or am I worrying for nothing? As I said, I'm a car hypochondriac, I like my machines running flawlessly 😅

Edited 2 June, 2022 by pcspinheiro

[pcspinheiro]

31 minutes ago, J.R. said:

 

Or not there (blocked) in this case judging by the video.

I don't know what to believe in anymore. I also read that, if everything is working well, there should even be a slight suction at the oil filler opening...

[J.R.]

Correct.

 

With a healthy engine and the PCV (positive crankshaft ventilation) system working well there would be some pulsing if you left the cap on loosely like you did but not of that amplitude and it should be sucking more in than pushing out.

 

Your oil consumption does not sound excessive & may be less than you think (depends on what level it was previously filled to), I would start by inspecting, removing, cleaning and testing the PCV valve & hoses, that alone may be responsable for the oil consumption.

 

I would also do a compression test to be certain.

[pcspinheiro]

XThanks for the replies. The car is still under a warranty extension plan, there's no way I'll get them to look at anything. The head mechanic will just put on his guessing hat and dismiss everything, as usual. What I need is to see other similar engines running to see if this is the norm or not for these 2.0L TDI...

[pcspinheiro]

12 hours ago, roottoot said:

This is how it used to be done.

*5,000 km not miles, by the VW Group bumf on the example of an owners manual at the bottom.*

 

Thanks for this, it's very thorough and good to know!

 

[pcspinheiro]

So, back to this after contacting what is supposed to be a knowledgeable ex VAG tech... I sent him the video showing the oil filler cap almost being blow off and all the smoke coming out. As a reply he LITERALLY called me stupid for opening the filler cap with the engine running, said this causes a massive pressure loss in the engine and turbocharging pressure and could even have caused loss of engine timing if this was chain-driven...? I don't know if he's being serious or just telling me off from touching the engine. Surely the oil filler cap cannot be such a crucial player in a engine's functioning, otherwise it would be inaccessible to the common user, OR have a big red flag "don't remove while in operation!"

 

So, again, I don't know what to believe regarding crankcase pressure. Is this normal or not? Seems excessive, if coming only from piston ring blow by...

 

Unrelated or not, I also started having some coolant loss, after 4 years of not touching it. Had to top it up once (took it to the dealer to let them know it was under the minimum. They topped it up and it has lowered a little already, in a couple of weeks... 

 

I refilled the oil to the top mark on the dipstick and took note of the Kms on the car. Will be keeping a close eye on theis. Hopefully, none of this is a problem, but if it is I want to catch while the car is still in the warranty extension period. 

 

Just yesterday I marveled at the simplicity of older cars: Did a full service on my 21 yo, 380.000 km petrol Opel Astra and that thing really just needs oils, filters and fuel. Starts first time every time, drives fine. Most repairs it ever needed i did myself, some harder than others, but no fuss.

[Breezy_Pete]

7 minutes ago, pcspinheiro said:

said this causes a massive pressure loss in the engine and turbocharging pressure and could even have caused loss of engine timing if this was chain-driven

Sounds like nonsense. 

I only have petrol engines to play with, but slight suction is what I know as normal, I'll take a vid when I get home if I remember.

If you're lucky @J.R. might do the experiment on his 2.0 TDI and describe the outcome for you.

[pcspinheiro]

Thanks Pete_Ex_Wino! It does sound like nonsense aimed at the gullible... Yes, I was sort of hoping someone (not afraid to doom their engine..) would just briefly see if they get the same as me on a similar 2.0 diesel. It's enough to unscrew the cap and screw it back on. 

 

I was curiously just going over the manual and nowhere does it say to !!!NEVER REMOVE THE OIL CAP WITH THE ENGINE RUNNING!!! If it was such a big deal to do it I'm sure there would be a warning in red in the manual. As there is for so many things

Edited 6 June, 2022 by pcspinheiro

[Breezy_Pete]

So on my car there is slight suction pulling the cap back down, resisting removal, at warm idle. Not sure how clearly this snippet shows it.

[pcspinheiro]

It shows perfectly, thanks. But that's a petrol, right? My very old astra petrol also doesnt blow the cap off, but I wonder how TDIs compare...

[Breezy_Pete]

Yes, naturally aspirated 1.4 4 pot petrol, 160k miles. So vacuum in inlet manifold makes PCV system relatively easy to implement. 

Edited 6 June, 2022 by Pete_Ex-Wino

[J.R.]

I tried

1 hour ago, Pete_Ex-Wino said:

If you're lucky @J.R. might do the experiment on his 2.0 TDI and describe the outcome for you.

I tried it and it caused a massive pressure loss in the engine and turbocharging pressure and  caused loss of engine timing

 

😆

 

I know why you suggested me, I'm the only one stupid enough to open the filler cap with the engine running, and do you know what, you are right!!!!!!

 

back in a minute!

[J.R.]

Guess what!

 

I tried it, there was positive pressure, the cap was jiggling up and down like the OP's, maybe not quite as bad but I didn't want to take my hand away as it was blowing out millions of dead mosquitos that had taken their last drink from the spillage ring, I did not want any to get in the engine.

 

In future I will make removing the cap with the engine running part of my maintenance regime to blow away any muck and foreign bodies which might otherwise get in during an oil change.

[J.R.]

My engine has done 110K miles & I think had a hard life for 80K before my ownership, it does not use a drop of oil between oil changes, no smoke visible on my test but I really should do it on a hot engine and remove the cap totally.

 

I will repeat the experiment in the week but for now I would say pulsating positive pressure if not normal is not causing any ill effects on my engine.

[pcspinheiro]

@J.R.Hahaha, this was both very helpful and made me laugh my butt off. Thanks!!!👍

[J.R.]

I have that affect on people!

[Micky 32]

I have a 2017 2.0 BiTDI 240 Passat. I have done 150k. My filler cap dances too just like in the video but my car doesn’t use a drop of oil between services. I suspect it’s normal for some of these engines.