If both have an API license or otherwise pass the requirements for one then it’s guaranteed they are miscible.
Mixing VR1 synth with 5w40 euro
- Thread starter PanteraMan74
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How do I verify that?
I looked and one does and the other one says it exceeds the requirements. So I would say they do.
Besides if the VR1 were really immiscible then there’d be a hecka warning on the container, as well as hecka lawsuits. I assure you Valvoline is lawsuit adverse
Both individual oils are better than the mix. Pick one and stop for the day. I'd say the Euro.
Better "Euro"? Then HPL, Redline, or Amsoil 20W-50.
Better "Euro"? Then HPL, Redline, or Amsoil 20W-50.
All we're saying here is: each oil will perform best on its own.
On the other hand - Click here to read about a guy who mixed 33 different oil brands and grades in one 5.0L supercharged engine, and ran it for ~3500 miles. In the name of science lol. That thread has the VOA and UOA screenshots in it. Last I heard - that engine ran great until rust killed that vehicle.
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Hell yeah dude science rocks
Sort of. A used oil analysis doesn't look at everything that happens to the oil in use. In fact it looks at only a small subset.
Why mix two different oils. Syn VR1 is a good oil and if 20W-50 is a bit thick?…mix in some 10W-30 Syn VR1. I ran a 50/50 mix of the two in my BMW bike for years.
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That’s a good idea actually
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I guess part of my concern with 20w50 is cold start flow, even in summer weather. I read so much about the 0/5w oils benefiting cold start protection that now I have reservations about running a 20w.
Flow is not an issue as long as the winter rating is appropriate for the starting temperature. In the summer an oil with a 20W winter rating is entirely appropriate, at that temperature the viscosity is going to be more similar to another winter rating than it will be different. The only guaranteed difference for a 5W rated oil is somewhat lower than about -30 and for a 0W it is below -35.
Besides it's not about flow here it is about pumpability. In the summer a 20W rated oil will pump, and if it pumps it will flow. On here sometimes "flow" is a phantom monster that has no relation to reality.
Go by the winter rating not by an imaginary worry over cold start protection. If you're not below freezing it won't make a whit of difference in protection.
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Interesting, people make it seem like 20w50 is going to flow like glue unless it’s 250°f. That was part of my reasoning to attempt mixing it. Being that my engine has massive valve spring pressure and a large cam I would think straight vr1 would be a good choice.
yeah, I see that too. What many people don't understand is that there's almost no wear difference between 0.5 seconds of oil pressure delay and 2 seconds of pressure delay. And even a 20w-50 will get you pressure under 3 seconds down to near freezing. So they "cold start delay" is a nothingburger until it's actually truly cold and oil pressure delay gets into the 5 seconds or more kind of range.
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I used to get my 302 Z28 started ok with 20W50 (early 1970s formulation), but at 20 below in Michigan it sometimes needed a jump start. Didn't seem to hurt anything.
This is the kind of anecdote I need to reassure myself I can run a 10W-xx oil when I may have a few single digit F starts or the very rare chance of a below 0F start. The allure of fewer FMs is appealing (in a high end oil).
For sure it hurt many things, but you cannot see them. At 20*F even 10W-30/40 are not doing well, especially if not synthetic.
I had once 10W-30 (conventional) in the engine at aboute 20-15*F the engine sounded aweful. I stopped at the first Jiffy Lube on the way to work and told them to dump the oil and pour any 5W-30. After that it was like night and day.
How exactly is a 10w-30/40 not doing well at 20*F? Can it not pump at that temperature?
A 10W-30 is 900-1,000 cSt @ 20°F. By comparison, a 5W-30 is 600-700 cSt @ 20°F.
While a 10W-30 is technically pumpable down to -14°F, you don't want to make the oil pump (and starter) struggle harder than they need to. I also don't like the idea of pushing tree sap through a cellulose filter. I like to give a buffer, keeping the maximum viscosity <1,000 cSt on cold starts.
4wd
$50 site donor 2026
Not seeing what is the coldest ambient you’d run this car?
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