AFN Engine Cold Start Knocking Noise

Hello,

I would like to find out how long the 'knocking' phase typically lasts for other AFN engines before the oil reaches the cylinder head.

'My car takes about 3-5 seconds to start in this situation, and the clacking noise is quite loud when the engine is cold. Once the oil has circulated, it runs normally. The current mileage is 206,000 km, and I use 10W40 oil; the performance is perfect.'

Is this normal, or should I be concerned about the lifters or something else?

I would say that 3-5 seconds is still acceptable.

I've even heard a relatively new Passat making ticking noises from the hydraulic lifters for 1-2 seconds.

Sure, you can replace the hydro cylinders and hope that fixes it, but my '87 JP ran perfectly fine for 10 kilometers with those same hydro cylinders!

Okay, please provide the German text you would like me to translate into English. I will only provide the translation.

Hi Boro,

Sure, I'll elaborate a bit more. I suspect you're referring to typical room temperature, around 20 degrees Celsius (68 Fahrenheit). In winter, the oil becomes thicker, and it takes longer for it to circulate.
What kind of oil are you using? What is your idle speed?
For me, with 0W30 oil, it's less than 2 seconds at idle (below 900 RPM).

'Pour in a thicker oil and it will take significantly longer!'

My recommendation: Use 0W30 oil that meets the Volkswagen standard.

@ Garth

Is the AFN not actually designed for 0W30 oil, or what?!?!

At least, there was no 0W30 oil available at the time of the introduction of the AFN engine.

Okay, please provide the German text you would like me to translate into English. I will only provide the translation.

Okay, I also use 0W-30 Longlife II (Castrol) oil in my Audi.
I don't know if it's good for the engine after 200,000 km.
"My tinnitus always lasts for about 3 seconds, regardless of the temperature."
After that, everything was quiet and no more metallic noises could be heard.
Let's see how this thing handles the oil. The fact is, it lubricates everything.

What I had to find out was that the oil consumption doubled from 0.1 to 0.2 liters per 1000 km. This happened since switching from 10W-40 Aral oil.
Currently, I'm driving on the highway and exceeding the speed limit according to the speedometer.

Hi,

I wouldn't necessarily use a very thin oil if the engine has high mileage.
You can certainly try it, but often the oil consumption increases significantly as a result.
I even use 15W40 oil in both my 1Z and now my AAT engine, and I experience very little oil consumption.

Based on my experience, the 'ticking sound' also depends on the oil LEVEL. When I keep it at the 4/4 mark (as I usually do), there's only a very brief ticking sound during startup (with 15W40 oil!).
If the value is only 1/2 at any point, it takes significantly longer.
Actually, I'm surprised that it makes a difference.

garth.brooks

Okay, I'm talking about the normal outside temperature! The idle speed is 900 rpm, and the oil, as mentioned before, is 10W40 from Globus, which presumably meets the VW 505 standard. I also switched to a thinner oil once, but then I had to add about 1 liter every 15,000 km. Currently, I have zero oil consumption, but if I drive at full throttle for an extended period, I need to top it up a bit. I suspect it's due to the turbocharger.

I'm just surprised by how extremely loud that clicking sound is! I think it was quieter a year ago. The other day, my car was parked in direct sunlight, and when I started it, there wasn't much noise at all?

Hello everyone,

Okay, I drive my AHU-TDI with 15W40 engine oil. The oil consumption is about 0.2-0.3 liters per 15,000 km. That's still acceptable. Since I'm not really a short-distance driver (short trips are murder for a diesel...), I can easily use slightly thicker oil. The hydraulic lifter ticking lasts about 1-3 seconds during cold starts, and 0 seconds during warm starts. Furthermore, I would advise against using thinner oils for vehicles with 'high' mileage (over 150,000 km), because the oil pressure suffers significantly, especially at idle. I can only relate this to older diesels, perhaps up to models manufactured in 1998 or so...
I witnessed a situation where four identical BMW 530 Touring models from 1997 (three of which had exceeded 350,000 kilometers using inexpensive 15W40 oil before experiencing automatic transmission problems) were used as company cars, and different types of oil were put into each one. Before that, all of them had around 130,000 kilometers on the odometer.
So, we have 2 cars using 15W40 and 2 others using 10W40. The oil was not topped up between oil changes, and the oil consumption was approximately 0.5 liters/15,000 km for the 15W40 oil and about 1-1.8 liters/15,000 km for the low viscosity oil. The oil pressure was noticeably lower with the low viscosity oil (of course, at lower engine speeds and when the engine was warm), but I don't know the exact numbers. Ultimately, the company manager decided to stick with the cheaper 15W40 oil.
While this result cannot be generalized to all engines, the data suggests that low-viscosity oils may not necessarily be beneficial for the engine. Considering how much more oil ends up in the combustion chamber, it's difficult to argue that they offer any real engine protection.
I haven't talked about gasoline engines here; that's a completely different story.

I'll stick with my 15W40 oil. The oil consumption is normal, and it doesn't seem to be harming the engine. Considering the weather we have in Germany, 15W40 seems like the best choice.

I didn't want to attack anyone or try to impose my views on them; it's just my opinion and experience.

Best regards, Georg.

P.S.: For my old Golf II 1.6 D, manufactured in 1985 (which has only seen cheap 15W40 oil every 10-12 thousand kilometers), after 250 thousand kilometers, pure mineral oil would be better suited than anything else.

@Georg-TDI
Hmm, both of the oils you described should have the same viscosity when warm (since they are both 40-grade oils). Therefore, the oil pressure should also be the same in warm engines.
The difference in oil consumption would theoretically only occur during the warm-up phase, as the 10W40 oil is naturally thinner than the 15W40 oil at that time.

/Jan

That's the thing...
'Low-friction oils are said to offer significant advantages during cold starts and the initial warm-up phase, but they shouldn't cause any disadvantages in normal operation (i.e., with a warm engine). Both types of oil should have the same viscosity when warm, but is that really the case? Can anyone confirm this phenomenon?'

In meiner Studienzeit hab ich einen Kumpel gehabt, der einen getunten Golf II GTI fuhr. Er hat auch alle mögliche Zusatzinstrumente gehabt (Öltemp. Ö(e.g., printing, etc.).
Since he often pushed his machine to its limits, he really wanted to use expensive, fully synthetic 10W40 lightweight oil. He reported that the cold starts were much better, with no more long hydraulic lifter ticking or smoke, etc. However, the oil pressure was always significantly lower when the engine was warm compared to using 15W40.
Ultimately, the car broke down due to a constant traffic jam caused by insufficient lubrication (according to the VW workshop), and the oil pressure light was constantly on when idling. This resulted in a major engine failure.
It's possible that there were still some other unresolved issues involved, who knows for sure...?

As I said, I haven't personally checked the oil pressure, and I don't have a way to do so. I'm just reporting what I've heard from others.

P.S.: Am I boring you with my long texts?

Hello,

Unfortunately, I have to read again about increased oil consumption with the use of synthetic oil.
I'm sorry, but that is simply incorrect! The theory has already been explained sufficiently.
Alle hier genannten Beispiele MÜSSEN andere Gründe haben (unterschiedliche Fahrweise, Luftfilterzustand, 2 versch. Mengines, etc.)
It's good that today's 15W-40 oils are sufficient to last for 300,000 km, and I don't want to dispute that, as long as you operate your vehicle properly (e.g., warming it up).

Best regards,

'@Dieselmartin - It says so in the instruction manual - For all temperatures below those found in the Sahara.'

@Georg-Markus and the others.

Sure, the oil consumption increases, but I always change it before winter, and often I find that instead of 15 liters, I actually use 18 liters. Also, my car is driven quite a bit, so everything is under more stress, and the amount of Russian-made components in the engine means there's also more contamination entering the oil. With my consumption of about 1.5 liters per year (for approximately 18,000 km), I find the consumption acceptable, even though it clearly increases with the thinner oil, as you described.

For this, my machine will be lubricated much more effectively and also cooled better.


I often see people here talking about oil temperatures of 120 degrees Celsius or more. Even with an outside temperature of 33 degrees, I haven't gotten mine above 110 degrees. Usually, even in the summer, it stays below 100 degrees.
Explanation: The thinner oil flows faster, which helps it cool more effectively.

But anyone who has experienced how a 15W40-filled engine performs in winter at -10 degrees Celsius and then switches to 0W30 will hardly recognize it anymore – and will likely stick with 0W30 from that point on.
Then there's also the effect that thinner oil can save a bit of fuel, although how much is debatable.

'@ Georg, always assuming the engine is otherwise okay. If the connecting rod bearings are already so damaged that the oil pressure drops, then it's not the oil itself that's to blame, but simply the faulty bearings. Using thicker oil might buy him some more time, but even then, it likely won't be much.'

Specifically for the connecting rods, rapid lubrication is crucial, much more so than for the hydraulic lifters. The connecting rods run on a thin film of oil until the oil pressure reaches it. The longer this takes, the higher the wear. Once the oil pressure is established, the components are bathed in oil, and the type of oil becomes less critical. Therefore, here too: the thinner the oil, the faster it flows = the better.

@ Albrecht - Regarding the comparison between 0W40 and 15W40, I agree with you – there shouldn't be any difference in oil consumption. However, here we are comparing 15W40 with 0W30, and in my experience, there was more [oil consumption]. But from my perspective, it was within an acceptable/desirable range.

Here's another thing: Take a look at the specifications of the oils. The number after the 'W' indicates their behavior at 100 degrees Celsius.
With 0W30, the viscosity increases more steeply than with 15W40. This means that the 0W30 exhibits a behavior similar to a 40 or 50-grade oil on hot parts like pistons. This is achieved through special additives and is one of the main requirements of the current VW standard for 0W30. At temperatures of at least 130 degrees Celsius, the 0W30 is thicker than a standard 15W40!
(Graph: SAE viscosity vs. temperature.)

'P.S. @Dieselmartin - I meant those.'

Here's a graphic that Garth mentioned:

http://www.castrol.de/schmierstoffe/3_viskositaeten/viskositaeten_6.html

Okay, please provide the German text you would like me to translate into English. I will only provide the translation.