I was wondering what everyone thought of blended oil. Synthetic and dino oil. Would you get the property's of synthetic and the reliability of regular oil. Thanks for your input...

 

I used to blend my own, using the same brand of syn and mineral (Castrol). I don't know if it helps. Lately, I just use the straight mineral, and change it regularly.

 

I use Valvoline Durablend. I don't know if it is really much better than dino, but it is cheaper than synthetic and gives me peace of mind that I am doing good for my engine. I think it helps on cold mornings. My engine seems to crank better with it.

 

I emailed Castrol about mixing Syntec 10W30 and Syntec 5w50 (both synth) and was surprised that they 'do not recommend mixing'. Their website addresses mixing synth & dino oil, I believe they say something like you can but you will lose the advantages of the synth. Their website has a FAQ section that gives more info on this issue.

 

Several articles I have read say that blended oils are just a way for oil companies to charge more for oil that isn't as good as synthetic and not a lot better than the dino. The cost of the oil blend from the factory is fairly low but the retail price is higher than the cost of the raw materials plus reasaonable profit.

Blending oils is good and bad. Technically any oil that meets the API spec for your engine must be blendable with other brands and types that are of the same spec. This in my opinion was probably a government or industry requirement to prevent bad things from happening from mixing dissimilar oils. So yes blending is supposed to work. However, when you mix dino with syn, you decrease the protection of syn but you also increase the protection from dino. I am not sure if the protection level is on a linear scale. I think it isn't, but have no proof of my own.

I have read that the additive packages each oil has is carefully blended with an eye to the interaction of all the components. Some components of the additives can have bad effects if in solution with other additives that are not supposed to be in the mix. So theoretically you roll the dice when you mix dissimilar oils, but you are protected by the lowest common denominator of the requirement for the oils to be mixable.

It would take far too long for me to write out all the reasoning and my memory is probably fuzzy on several accounts. There is a good study on the web that discusses the attributes of all the common additive packages used by the major oil companies and the effect of adding other additives not in that package. No I don't remember where I found it, you'll have to do a search just like I did a few years back. If several people beg me I will look in my garage for the hardcopy and post the URL, but it really is easier and more fruitful if you search for yourself. There is a lot of good reading on the web.

The bottom line in my opinion is that synthetics are probably overkill for most uses, but I still use it for almost all my engines, just like that extra margin. Dino is excellent oil and is more than adequate for most uses. Blends are also excellent but their price is not commensurate with the marginal additional protection they give. Blending oils is OK within API spec families but the end results may be a minor crapshoot. Almost surely nothing bad will happen with any of these choices. The only thing that is recommended against is brewing up your own additive pacakages or using an aftermarket package, in most cases. Regular maintenance is probably the most important thing, as long as you use products within spec.

I am not an expert, I've just been doing cars for fun for a long time, so read for yourself and make your own judgements. You will get arguments all over the place, these are just my opinions.

Jim Henderson

 

Blends probably have a benefit in cold starting. Maybe less VI improver additive needs to be added compared to straight dino stuff.

100% synthetics are death to aircraft engines, yet blends are very popular (15w50 AeroShell).