Audi A4: 0W-30 Oil for MKB-AVG Engine?

Hello.
Just a quick question.
Is the 0W30 Longlife II oil also approved for the A4 with a 110 HP TDI engine, manufactured in 2001?
Regards,
Mirco.

Hi,

It depends on the viscosity: 0W30. For my AFN engine, it is approved, although not for very high temperatures.

You can always add Longlive, but that doesn't necessarily mean you have to extend the interval.
That stuff is so much more expensive that you're better off using regular full synthetic 0W30 oil and changing it more frequently.

BUT: It must comply with the VW specification listed in your owner's manual; otherwise, don't use it and choose a 5W40 instead!

I'm currently using ARAL 0W30 oil, I top it up by about a liter every 6,000 kilometers, and I change it annually in December, after approximately 18,000 kilometers.

Dec. Therefore, because the fresh, thin oil provides significantly faster lubrication in the winter, and the engine doesn't run nearly as sluggishly from the moment it starts. Oil consumption increases slightly, but not dramatically.

It's a matter of cost; it only pays off if you buy it in large quantities at a low price, like with tires from reifen.de.

In regular retail settings, this stuff is either unprofitable to sell or outrageously expensive.

Okay, I wouldn't necessarily use 0W30 oil in my engine. If I were to use something, it would be 0W40. I'm not sure why VW uses 0W30 for their 'Longlife' specification. It's thinner when it's warm, which can result in lower oil pressure.

Best regards, WarLord.

@ Warlord

Hi,

The lower oil pressure at idle, especially when the engine is cold, is not necessarily a disadvantage.

Higher oil pressure simply means that the oil pump has to exert more force to pump the oil to where it needs to go. This also means that it takes longer for the oil pressure to build up during a cold start.

Thinner oil reaches the bearing faster. For plain bearings, the (shortest possible) time it takes for the oil pressure to build up at the bearing is crucial, and the flow rate is key, which is achieved more quickly with thinner oil.

Thinner oil is generally more effective at cleaning the engine than thicker oil. It also has more reserve capacity regarding thickening due to soot and wear.

The only problem I'm aware of is that, at high piston temperatures, the lubricating film is more likely to break down with thinner oils.

However, the splash lubrication of the pistons is also better with thinner oils, because at a constant oil pressure (i.e., an engine speed significantly above idle), the flow rate through the splash nozzles is higher, which results in better lubrication of the pistons.

Therefore, the approved 0W30 oils contain additives that cause these 30-weight oils to behave like 40-weight or 50-weight oils at temperatures above 100 degrees Celsius.

That's why I would like to emphasize the importance of using ONLY approved oils.

@ Warlord

Hi,

The lower oil pressure at idle, especially when the engine is cold, is not necessarily a disadvantage.

Higher oil pressure simply means that the oil pump has to exert more force to pump the oil to where it needs to go. This also means that it takes longer for the oil pressure to build up during a cold start.

'The thinner oil reaches the bearing faster. For plain bearings, the (shortest possible) time it takes for the oil pressure to build up at the bearing is crucial, and the flow rate is key, which is achieved more quickly with thinner oil.'

Thinner oil is generally more effective at cleaning the engine than thicker oil. It also has a greater reserve capacity regarding thickening due to soot and wear.

The only problem I'm aware of is that, at high piston temperatures, the lubricating film is more likely to break down with thinner oils.

However, the splash lubrication of the pistons is also better with thinner oils, because at a constant oil pressure (i.e., an engine speed significantly above idle), the flow rate through the spray nozzles is higher, which results in better lubrication of the pistons.

Therefore, the approved 0W30 oils contain additives that cause these 30-weight oils to behave like 40-weight or 50-weight oils at temperatures above 100 degrees Celsius.

Therefore, my advice is to ONLY use APPROVED oils.

Hmm, but if the oil behaves the same way as a 0W40 or 0W50, why doesn't it have that designation? Doesn't the last number indicate that it behaves like an SAE 30 when it's warm or hot, and isn't that oil less viscous when it's warm? However, the more viscous the oil is, the higher the oil pressure (I read that somewhere on the internet). I would appreciate it if someone could clarify whether this information is correct. But if that's not the case, why do people use 10W60 or something similar in motorsports?

Best regards, WarLord.

Hi,
The viscosity is temperature-dependent and exhibits a non-linear relationship, forming a curve that resembles a hyperbola. The number preceding "W" indicates the viscosity at -18°C, while the number following "W" indicates the viscosity at 100°C. The standard does not specify how the curve continues beyond these points.
Therefore, Volkswagen has imposed additional requirements.
Example 5W40: Apparent viscosity at -18°C is less than 3.8 mPa s, and at 100°C, the kinematic viscosity is between 12.5 and 16.3 mm²/s.
In racing applications, engines are subjected to extremely high loads, which results in correspondingly high temperatures. The behavior during cold starts is irrelevant, as are issues related to deposit formation or sealing after 200,000 km.