how much of a 5w40, say rotella t synthetic, would you have to mix with a 15w40 like rotella t dino to get the benefits of the 5w40. im thinking about doing this in the winter and would like the easier starting and maybe even better mileage associated with the 5w40, but don't want to go completely to the 5w40 because this is an older motor, over 100,000 miles and has a front and rear main leak. my crankcase capacity is 7 quarts. just curious if anybody has tried this before?
mixing benefits of a 5w40 with a 15w40
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I've not tried this mix exactly, but my guess is that you'd want at least 30% syn, or about 2 qts in your engine. However, if it were me, I'd dump in an entire 4 qt jug of syn & fill the remainder with dino. It'll be a lot easier to mix/measure, & you can safely (& easily) top-up with dino throughout the interval.
Why not try Mobil1 15w50 with Mobil1 0w30 or 5w30?
I bought 4L jug of 15w50 at Canadian Tire 2 weeks ago for 27.27 tax included. They also had 5w30 and 10w30 for the same price.
Steve
I bought 4L jug of 15w50 at Canadian Tire 2 weeks ago for 27.27 tax included. They also had 5w30 and 10w30 for the same price.
Steve
I was using Exxon 15-40W XD3 Elite, a synthetic blend, but couldn't find it anymore so I started making my own blend with 25% Mobil 1 Truck & SUV and Delvac 1300. I'll use a 33% blend in the winter. Don't see why Rotella wouldn't work.
I guess I'm not getting why you want to mix? Are you are thinking of getting a thicker oil so it doesn't leak? If so, you could use Amsoil SAE 10W-40 Synthetic High Performance Motor Oil http://www.amsoil.com/products/amo.html If that isn't what you are trying to achieve, please clarify.
Whoah
What are you putting this in? You have a Diesel don't you? if so the best overall oil to use is a 15w-40... Pick a brand you trust and don't worry.
Just as you aren't supposed to put any Striaght weight oil in one doesnt mean it can't happen... My neighbor took some of my striaght 30w because he was using a cheap 2/1.00 no named oil for gasoline only in his Benz... Well I gave him the 30w because at least it was formulated for diesel.
Just because it is not designed for it doent meant it wont run, but you don't wanna go there I don't think! JMO
As for mixing the Rotella 5w-40 with the conventional 15w-40 I had asked them about that when it first came out. Their opinion was NO.
Perhaps mixing gets you the worst of each oil rather than the best.....
Perhaps mixing gets you the worst of each oil rather than the best.....
When they say compatible, they are. But by mixing viscosities, yoy are not getting the vis you think you are. Some think if you mix 2 qrts 0w-20 and 2 qrts 10w-40 you will get a 10w-30 and you will not. I believe you will still have the thinner viscosity.
The thinner viscosity is fine for my intended use. In the truck I mix 9 qts of Delvac 15w-40 and 3 qts of Mobil 1 T&S 5w-40, so there shouldn't be a problem with the 40 weight, and thinner than an assumed 12.5 is fine for better cold starts. In the cars I mix 1 qt of Mobil 1 T&S 5w-40 with either 4 qts of Mobil 5w-30 or Mobil 10w-30, so thinner is again fine.
I mix because some synthetic has appeared to help with cleaning and making the older car run better, because it seems to make for less engine noise in the truck, because it will help a bit with cold starts in the truck, and because I don't want to spend either approx $25 for oil in the cars or $60 for the truck. In summary synthetics seem to offer some benefits for my vehicles and while I won't pay what they're asking for 100% usage I will pay an extra $4 (car) to $12 (truck) for the perceived benefits.
Extended oil drains aren't attractive in the cars as they're used for mainly short trips, and they aren't in the truck because I need to do 3750 mile oil changes for warranty purposes since Dodge/Cummins states that intervals can't be extended just because a synthetic is used.
I mix because some synthetic has appeared to help with cleaning and making the older car run better, because it seems to make for less engine noise in the truck, because it will help a bit with cold starts in the truck, and because I don't want to spend either approx $25 for oil in the cars or $60 for the truck. In summary synthetics seem to offer some benefits for my vehicles and while I won't pay what they're asking for 100% usage I will pay an extra $4 (car) to $12 (truck) for the perceived benefits.
Extended oil drains aren't attractive in the cars as they're used for mainly short trips, and they aren't in the truck because I need to do 3750 mile oil changes for warranty purposes since Dodge/Cummins states that intervals can't be extended just because a synthetic is used.
The Mobil site states "Mobil 1 Truck and SUV is fully compatible with conventional engine oils.", which I assume means that it's fully compatible with conventional engine oils :^) I assume 'fully compatible' would include adding a quart of Mobil 1 T&S to an engine that has dino oil in it, not having to flush the engine with ? when changing from another oil to Mobil 1 T&S, or adding a quart of Mobil 1 T&S to 4 qts of Mobil 10w-30 dino oil during an oil change.
Mobil and other companies provide synthetic blends that are positioned between dino oils and synthetics, in price as well as advertised performance.
Mobil and other companies provide synthetic blends that are positioned between dino oils and synthetics, in price as well as advertised performance.
About 5-6 years ago I went to the tribologists at Mobil with a similar question. My question was, when using Delvac 1 in my Mercedes diesel if I needed to top up the oil, but Delvac 1 wasn't available, would it be better to use Mobil 1 15W-50 or Delvac 1300 15W-40?
Their team couldn't agree on an answer but all agreed there was NOT a problem. Some suggested that using Mobil 1 would provide the additional benifts of synthetic, while the other side felt that the additional protection of the CH-4 additive package was an advantage. Neither felt that there would be any serious compromise in performance even if the two were mixed in almost equal quantities and the properties would at least equal and probably exceed the properties of the "inferior" oil.
I do not know of ANY synthetics that does not claim to be entirely compatible with all conventional oils, but some synthetics claim they may NOT be compatible with other synthetics.
In my own experience mixing Delvac 1300 with Mobil synthetics, I found no clearly detectable increase in cold cranking speed and thus cold weather starting until the quantity of synthetic was about 50% and the quieting influence that synthetic exerts on the valve lifters (or followers) quickly diminishes once the synthetic concentration drops much below 70-75%.
As for starting in cold weather, most group III oils are considerably inferior to the best group IV oils. I played with mixing Mobil 1 0W-30 or 5W-30 with 15W-50, but quickly abandoned that as I don't need to start in weather below about -20 (F) and Mobil 1 15-50 allows that without playing with adding anything (I culd not detect any change in cranking speed) and with M-1 5W-40 or D-1 cranking speed and thus cold starting was even a little bit better.
Marshall
Their team couldn't agree on an answer but all agreed there was NOT a problem. Some suggested that using Mobil 1 would provide the additional benifts of synthetic, while the other side felt that the additional protection of the CH-4 additive package was an advantage. Neither felt that there would be any serious compromise in performance even if the two were mixed in almost equal quantities and the properties would at least equal and probably exceed the properties of the "inferior" oil.
I do not know of ANY synthetics that does not claim to be entirely compatible with all conventional oils, but some synthetics claim they may NOT be compatible with other synthetics.
In my own experience mixing Delvac 1300 with Mobil synthetics, I found no clearly detectable increase in cold cranking speed and thus cold weather starting until the quantity of synthetic was about 50% and the quieting influence that synthetic exerts on the valve lifters (or followers) quickly diminishes once the synthetic concentration drops much below 70-75%.
As for starting in cold weather, most group III oils are considerably inferior to the best group IV oils. I played with mixing Mobil 1 0W-30 or 5W-30 with 15W-50, but quickly abandoned that as I don't need to start in weather below about -20 (F) and Mobil 1 15-50 allows that without playing with adding anything (I culd not detect any change in cranking speed) and with M-1 5W-40 or D-1 cranking speed and thus cold starting was even a little bit better.
Marshall
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