Many car handbooks advise use of very specific oils to use that are certified to meet manufacturer specification.

What is the consequence of using the same weight/viscosity/type oil (e.g. "5w30 fully synthetic") without the manufacturer spec (e.g. "5w30 fully synthetic meeting vw 505 01")?

I imagine with a new car it may affect manufacturer warranty but for older vehicles will it matter? If oil is topped up with the unbadged version when other oil is not available, is an oil change needed as soon as possible or can it wait?

(If the type of car matters, in our case we run a 2007 octavia diesel without dpf, though this would be a more useful q/a if it can be kept more general)

  • Did you look for similar questions on here before posting?
    – Solar Mike
    Commented Jun 9, 2020 at 10:12
  • I found some questions about different weight/viscosity (e.g. 5w30 vs 5w40) and synthetic vs semi synthetic. But not specifically about the difference between manufacturer certified vs generic oils. My understanding (which may be wrong) is that some of these are blends of different weights, and some engines are more sensitive than others, so I thought this question worth asking. Commented Jun 9, 2020 at 11:08

3 Answers 3


There can be more to it than "just" the weight/viscosity when it comes to a manufacturer specification. This can be a question of detergent/cleaning component content, operating life, operating temperature ranges and behavior, properties that can effect DPFs and so on.

They aren't always a big deal, and sometimes it can be nothing more than a case of needing to change a bit more regularly or some slight increase to wear.

Other times however it can be a bit more serious. Taking the example from your post - that of an '07 Non-DPF Octavia, presumably this is one with the 1.9 PD engine. The PD engine could be severely affected by using non- 505.01 oil, to the extent that VW issued a TSB about it. Including this cheery bit of advice:


Failure to use engine oil for your engine that expressly conforms to Volkswagen oil quality standard VW 505 01 can cause engine failure on the highway that can cause a crash and serious personal injury.

That's not to say you need always buy VW-branded or even particularly expensive oil, just make sure it's listed as compliant with the relevant specification and you're good to go.


From here:

Oil Specifications

We have:

VW 505.01 Special engine oil for VW turbodiesel engines with pump-injector-unit and for the V8 Commonrail turbodiesel engines. Meets ACEA B4 SAE 5W-40 specification.

So in order to meet their requirements and maintain your VW warranty, you must use an oil that meets or exceeds their specs. But you do NOT have to use their brand of oil.

ACEA B4 is a common diesel engine oil. Look for this certification as well as 5W-40 on the bottle and you're good to go. Keep records of when, the mileage, and the type of oil in case you get challenged at some point in the future.

  • It's worth pointing out that VW 505.01 spec meets ACEA B4 - not that the same is necessarily true in reverse, e.g. this meets ACEA B4 but is only VW 505.00 so wouldn't be suitable for a PD engine. Commented Jun 9, 2020 at 15:59

On gas engines the viscosity can be very important as on late models with variable valve timing rely on oil pressure to work properly. Also machining has become more precise including oil passages. In order for the most efficient oil distribution it is more and more important to use the recommended oil type and grade.

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