Oil burner question 10W40/5W30

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So my 2004 Jetta has an oil consumption problem with rings that were installed backwards. It's a well known problem of the MKIV Jetta - around 1 quart per 1000 miles during summer. I just did an oil change with 10w-40 weight and also mixed in some 5w-30. Let's call it 50/50 10W40 and 5W30.

Will the 5W-30 part of this blend be consumed at a faster rate than the 10W-40, or does it all just get mixed together. All valvoline. The 10W-40 is the maxlife syn blend. The 5w-30 is dino.
 
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I only drive the car 6K miles a year and with the consumption problem, I don't really need a super aggressive OCI , as oil is always fresh.

So this year instead of changing before and after winter, I decided to forgo the before change and drive a heavier weighted blend right through winter. Of course, we had one of our coldest winters of the year, but she turned over like a champ with only a couple that were tough cranks, even at below 0, where 40 weight starts to get real thick. So I judged that experiment a success.


This year, since the 5w-30 jug is open, I'll strictly be topping up with the lighter oil. By the time winter rolls around, should be mostly 5W-30( if they do truly mix.)
laugh.gif
 
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Originally Posted By: Snagglefoot
I’d recommend a 10-40 without mixing in anything.


I get it with the thicker oil = less consumption, less heat, better for old engines. But I've actually found it doesn't make a huge difference in my application for consumption. Maybe 25% less, possibly up to 50%? Given the low mileage I put on the car , not a huge deal.

My plan was to do do straight 10W-40 today, and then top up with 5W-30 right through to oil change next year. However, I only had 3 quarts left of the 10W-40, the last quart in was 5W-30. I indicated 50/50 in OP just to simplify.
 
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Originally Posted By: lairdwd
So my 2004 Jetta has an oil consumption problem with rings that were installed backwards. It's a well known problem of the MKIV Jetta - around 1 quart per 1000 miles during summer. I just did an oil change with 10w-40 weight and also mixed in some 5w-30. Let's call it 50/50 10W40 and 5W30.

Will the 5W-30 part of this blend be consumed at a faster rate than the 10W-40, or does it all just get mixed together. All valvoline. The 10W-40 is the maxlife syn blend. The 5w-30 is dino.
 
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Originally Posted By: Linctex
All mixed together.

The blend will "act" much more like a 10W-40 than a 5W-30.


Why so?

IIRC mixtures are generally skewed towards the lower viscosity component.

(Alhough with multigrades you don't really know exactly what's going to happen.)
 
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Originally Posted By: Ducked
Originally Posted By: Linctex
The blend will "act" much more like a 10W-40 than a 5W-30.


Why so?
IIRC mixtures are generally skewed towards the lower viscosity component.


In the winter it is different - the mix acts like the heavier oil.

If you are resourceful, you can find 5W-40 on sale or clearance.
I have about 6 gallons of it, all bought for well below sticker price.
 
Originally Posted By: Linctex
Originally Posted By: Ducked
Originally Posted By: Linctex
The blend will "act" much more like a 10W-40 than a 5W-30.


Why so?
IIRC mixtures are generally skewed towards the lower viscosity component.


In the winter it is different - the mix acts like the heavier oil.



I have heard of this "winter" of which you speak.

You got a source/ref for that, or is it based on personal observation?

I ask because offhand it doesn't seem to make sense, since temperature is already built in to the grade specifications.

I believe multigrade mixtures can be unpredictable though.
 
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Originally Posted By: Ducked

I have heard of this "winter" of which you speak.
You got a source/ref for that, or is it based on personal observation?


Just search the topics on this forum.

Look for pour point depressants, cold weather etc etc

Yes, one tablespoon (10 ml) of 20W-50 in an entire sump of 0W-20 will not affect it that much, but thick oil in the winter makes all of the oil thicker.
 
If running the mix year round...
When topping off in the fall use 5w30 to thin it out a bit more for winter.
I wouldn't top off with 10w40 in the winter
 
Originally Posted By: Linctex
Originally Posted By: Ducked

I have heard of this "winter" of which you speak.
You got a source/ref for that, or is it based on personal observation?


Just search the topics on this forum.

Look for pour point depressants, cold weather etc etc

Yes, one tablespoon (10 ml) of 20W-50 in an entire sump of 0W-20 will not affect it that much, but thick oil in the winter makes all of the oil thicker.


Of course thick oil makes a mixture thicker (at any time of year). That's not in dispute, nor is it what you were saying earlier.

You said, effectively, that in a 50/50 mix of thick and thin oil the resultant mix will be skewed toward the thick end.

Thats certainly incorrect for straight oils. I'd be surprised if multigrades are sytematically the opposite of straight oils, though I know they are not entirely predictable,

The time of year is surely irrelevent. The grade of an oil is defined with respect to reference temperatures, not the calendar. Presumably what you mean is the effect is mostly seen on the first number.
 
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