Straight 30 weight

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I recently tried some castrol straight 30 weight, and did a hot oil drain at 500 mile, in 50 degree weather. This stuff was so thin it was like water although the film stregth felt good.

Why is it even thinner than a 10w30 at full temp, I thought they were supposed to be equal?

Is this oil thinning too thin?
 
Originally Posted By: Mackelroy
I recently tried some castrol straight 30 weight, and did a hot oil drain at 500 mile, in 50 degree weather. This stuff was so thin it was like water although the film stregth felt good.

Why is it even thinner than a 10w30 at full temp, I thought they were supposed to be equal?

Is this oil thinning too thin?

Do you know how hot the oil itself was?

A straight-30 should be in the same RANGE as a 10w-30 at 100 degrees C, but one can still be thicker or thinner than the other.

If your oil was hotter than 100 degrees C when you drained it, it's entirely possible that the straight-30 was thinner. It probably has a lower viscosity index than the 10w-30, which MIGHT mean that it will thin out more as it heats up.
 
These are hot drains , multihours on the road

The case of straight 30 castrol,outside temp was 55 degrees , and I was running around 180 water temps sustained, as mentioned multihoured. Shut off and drain

I was shocked at how thin it drained like water, not what I was expecting.
 
Originally Posted By: Pablo
Without running an actual viscosity, it's pretty hard to judge a couple cSt.


The difference was very dramatic compared to any 1ow30 hot drain i've done , scarey thin would be my observation.
 
In Australia Penrite makes 40-70 oil for older V8s and whatnot. It has 1760ppm Zn and 1600ppm P.

Charlie
 
Originally Posted By: Bluestream
How did you measure the film strength?


Finger print method


I switch back to 10w40, cause I thought straight 30 too thick for sub 55 degree weather , but above draining it was so thin, it was shocking.
 
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Originally Posted By: Pablo
Without running an actual viscosity, it's pretty hard to judge a couple cSt.


+1, it is just margin of error and perception of difference...
 
""I was shocked at how thin it drained like water, not what I was expecting.""

depending on temp and even the light hitting the oil you can not compare oils in vis by eyeball of fingers it may LOOK thin and it maybe, but unless tested you are only guessing

bruce
 
From an old dude: In 1967 the wife and I had a brand new 1967 VW Beetle, wow,,high performance ugh..not, 58 hp I think and 2 1/2 quarts of oil and a screen filter with a magnet,lol. really. Never thought about engine oil heat and how it poured when hot,,the car ran, and thats that, things were easier once.

We only used 30wt in the south then, two qt of oil might have been 2 bucks maybe. So, things were simple, the little engine was 1500cc and ran and ran and ran. Did I say the car was 1600 bucks plus tax..it cost 4 bucks to go 400 miles, can remember driving to another exit to find gas for 33 cents a gallon, on base it was a 22cents a gallon, turn back the clock.....................fly Navy life was way simple then, now its mass confusion, but life goes on..............
 
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