German Castrol Pumpability Poor GM6094M

Status
Not open for further replies.
I will say that in Iowa, we can see as low as -30*F and as high as 110* with ridiculous humidity..

Fallguy, where in the heck in this stinking state are you finding GC?
 
Originally Posted By: The_Eric
I will say that in Iowa, we can see as low as -30*F and as high as 110* with ridiculous humidity..

Fallguy, where in the heck in this stinking state are you finding GC?


Have not looked for any yet but see I can have it shipped to store (AutoZone) and pick up, would need to then confirm on back that it is "German".

German Castrol appears to be made from a higher iv base stock some believe. America is tooled up to only crack and refine as a base 3 synthetic, hence why the 0w30 is imported ie made in a country set up for the euro specs of the oil I would guess.

Just saw on Castrol's product data sheets that they were well beyond the cold pumping GM spec but does appear Castrol just populated the data with default numbers across all the weights in the syntec oils.

Will probable run this in my out of warranty ranger and keep the impala on 5w30 Valv Synpower (seams to stay in the 30 grade good compared to PP, RP or Edge) (tbn gives out somewhat early however).
 
Last edited:
Here is the Email I just sent off to Castrol.

What is the -40C pumping viscosity of Syntec 0W30 ?

The product data sheet list an incorrect value that I think is just a default number of the grade and not an actual indicator of this oils pumping viscosity at -40C.

Want to use this oil but concerned if the -40C pumping viscosity is anywhere near 60,000 cP Most other brands 0w30 oils are well below 30,000 cP at -40C

Regards,
 
Originally Posted By: Audi Junkie
Isn't 6094M the most basic of specs?

Yeah, too bad the Lubrizol tool doesn't show this spec so that we could compare it against some of the others.
 
Originally Posted By: rpn453
Originally Posted By: Fallguy
What is the difference between cP and cst as GM spec is in cP and calculator is in cst ?


I've never really differentiated between the two for motor oils. There is a difference, but not a big difference. cSt is used for absolute viscosity. The kinematic viscosity (using cP) just incorporates the density by dividing the absolute viscosity by the specific gravity of the fluid. Since the specific gravity of a motor oil is reasonably close to 1, and gets even closer in cold temperatures, the units are similar enough for our purposes. The SG of GC is 0.847 near room temperature, so the cP value will be 18% higher but will become closer to the cSt value as temperature falls. Based on the little information I can find on the effect of temperature on oil density. I'd estimate that a typical motor oil would be at about .92 by -40C; a 9% difference.


If you're talking about MRV, which is a measure of viscosity while being pumped then you must also factor in the pressure-viscosity coefficients of different oil chemistries. Consiquently, there are simply too many variables to practically compare the simply kinematic viscosity (cSt) measure with other more accurate and applicable viscosity measures like MRV.

Ultimately if you want to know the relative viscosity of an oil at any given start-up temperature is to install an oil pressure gauge. That's assuming the oil in question is light enough not to
cause the oil pump to go into by-pass on idle.
 
Originally Posted By: CATERHAM
If you're talking about MRV, which is a measure of viscosity while being pumped then you must also factor in the pressure-viscosity coefficients of different oil chemistries. Consiquently, there are simply too many variables to practically compare the simply kinematic viscosity (cSt) measure with other more accurate and applicable viscosity measures like MRV.


We're not using any measures of kinematic viscosity at low temperatures, only calculated values.

As far as I know, conversion involves only this basic equation:

Kinematic Viscosity [cSt] = Absolute Viscosity [cP]/Density [g/cm^3]

Do you have a more comprehensive formula or explanation for why this is inadequate?
 
Originally Posted By: Audi Junkie
I just stick with comparos from temps I actually will encounter. What kind of temps are you getting up there? -25f? PP 5w-30 is still the winner in my book. You get a good price on GC up there, don't you? What about XD-3?


Makes sense, but there just isn't much hard information in that temperature range.

I stick to 0W oils exclusively in winter because we see -40F at least once a year. My coldest cold start (sitting all night, not plugged in) was -44F on M1 0W-20. I'd prefer a 0W-20 in winter if it were more readily available here. GC is the cheapest 0W-30 I can easily buy. Strangely, it's even cheaper than Tech2000 0W-30. It's possible that the bulk distributors might have XD-3 or something cheaper, but I'm never in that area of town.
 
Why do you want to run GC in a GM 3.5?? It will do fine on PYB 5w30. There's a guy here that just went 11K on it in his Malibu with the 3.5 with exellent UOA results.

There are engines out there that benefit from a thicker oil...yours isn't one of them IMO.
 
Originally Posted By: rpn453

It's possible that the bulk distributors might have XD-3 or something cheaper, but I'm never in that area of town.


XD-3 has properties similar to GC. It's on the thick side @100C and is 0W rated. If you don't need thick @100C, you don't need GC or XD-3 0W30.

Some Walmarts seem to have XD-3 0W30 and most seem to have 0W40. I've also been told that Home Hardware carries or can order anything from the XD-3 lineup. If you have one in your area it might be worth asking.
 
Originally Posted By: Craig in Canada
Some Walmarts seem to have XD-3 0W30 and most seem to have 0W40. I've also been told that Home Hardware carries or can order anything from the XD-3 lineup.


I have never seen XD 0W30 at Walmart but yes I do order it from HH. Easy to do.
 
Originally Posted By: rpn453
Originally Posted By: CATERHAM
If you're talking about MRV, which is a measure of viscosity while being pumped then you must also factor in the pressure-viscosity coefficients of different oil chemistries. Consiquently, there are simply too many variables to practically compare the simply kinematic viscosity (cSt) measure with other more accurate and applicable viscosity measures like MRV.


We're not using any measures of kinematic viscosity at low temperatures, only calculated values.

As far as I know, conversion involves only this basic equation:

Kinematic Viscosity [cSt] = Absolute Viscosity [cP]/Density [g/cm^3]

Do you have a more comprehensive formula or explanation for why this is inadequate?



Not sure what one is trying to achieve in calculating a kinematic
value at sub-zero temps. Kinematic viscosity correlates poorly with the operational viscosity in an engine so why bother to estimate a value when an MRV viscosity spec' is available?
 
imo, the visc calc is fine for *comparing* different oils at near sub zero temps. If you have an oil that's thinner at -10f, it's likely thinner at -20f too, and both temps are not really relevant for me anyway, I see 0f a once or twice a year.

Again, if you're looking at cold weather performance, GC isn't the place to look. afaik, in extreme cold, operating temp is reduced too, so a thinner grade can be substituted.
 
Originally Posted By: CATERHAM
Not sure what one is trying to achieve in calculating a kinematic value at sub-zero temps. Kinematic viscosity correlates poorly with the operational viscosity in an engine so why bother to estimate a value when an MRV viscosity spec' is available?


Just trying to compare the results of the Widman calculator, which is in cSt, to published specs. It appears the calculator isn't designed for the really low temps though.
 
Status
Not open for further replies.
Back
Top Bottom