Snagglefoot beat me to it - Pennzoil Euro becomes 'cheap' when bought on sale and after the $10 / jug rebate.
You would have to look at the spec sheet for each oil and compare the CCS and MRV viscosity numbers. A 0W will have less CCS and MRV viscosity vs a 5W, and a 5W will have less CCS and MRV viscosity than a 10W.So as a general person looking to fill the "what should I buy to get oil flowing ASAP in really cold weather". What are the recommended CCS/MRV viscosities for what temp ranges? Is there a list of them easy to find without going to each brand/viscosity data sheet?
The hardest part of the whole mechanism is getting the cold oil into the pick-up tube. Once it gets there it will make it's way to the pump and be sent into the oiling system.That’s what the winter rating is for. Flow is irrelevant really, it’s about cranking and pumpability. If the oil can be pumped it will flow.
Pumpability is a binary. If it can’t be pumped it won’t flow. But if it can be pumped then it will flow. Flow doesn’t lubricate the engine, the film thickness does.
Typically the CCS is the limiting factor whether an engine oil gets a pass or fail on a given W grade.You would have to look at the spec sheet for each oil and compare the CCS and MRV viscosity numbers. A 0W will have less CCS and MRV viscosity vs a 5W, and a 5W will have less CCS and MRV viscosity than a 10W.
But if you really want to split hairs you start comparing the CCS and MRV numbers between different oils of the same W rating - ie, just compare 0W oils to 0W oils and 5W oils to 5W oils. If you want the very best cranking and pumpability you would choose a 0W grade oil with the least CCS and MRV viscosity between them all. SAE J300 defines the max limits for each W grade - latest version shown below. Of course there are other aspects of motor oils that should be looked at besides just the W rating ... but what I said above would just be focusing on the W rating aspect.
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Yep, the last thing you want is for the engine to crank and start, without the oil being able to be moved by the pump. And look at the viscosity difference at the same test temperatures between the CCS and MRV viscosity in J300. MRV viscosity limits are roughly 9 to 10 times higher than the CCS viscosity at the same temperature. And MRV limits are defined and tested at 5 deg C lower than CCS limits.Typically the CCS is the limiting factor whether an engine oil gets a pass or fail on a given W grade.
The MRV usually passes at least one grade colder than the CCS.
The theory being and how the W grades were established, that if the engine starts. the oil will pump and flow.
Interestingly, the MRV limit used to be lower with the old testing apparatus.Yep, the last thing you want is for the engine to crank and start, without the oil being able to be moved by the pump. And look at the viscosity difference at the same test temperatures between the CCS and MRV viscosity in J300. MRV viscosity limits are roughly 9 to 10 times higher than the CCS viscosity at the same temperature. And MRV limits are defined and tested at 5 deg C lower than CCS limits.
While on the topic of pour points, I think that gear lube channel points and pour points correlate somewhat.Yep, the last thing you want is for the engine to crank and start, without the oil being able to be moved by the pump. And look at the viscosity difference at the same test temperatures between the CCS and MRV viscosity in J300. MRV viscosity limits are roughly 9 to 10 times higher than the CCS viscosity at the same temperature. And MRV limits are defined and tested at 5 deg C lower than CCS limits.
Gear and transmission lubes typically don't use a PD pump, and therefore the dP the pump creates in an engine's sump pick-up tube isn't in play in a transmission or differential. So yes, pour point (the ability of the oil to flow just from gravity) would be representative of the oil flowability and therefore lubrication ability in a system where there is no forced lubrication by a PD oil pump.While on the topic of pour points, I think that gear lube channel points and pour points correlate somewhat.
For example, the 80w140 synthetic gear lube I used shows a pour point if -37C. I feel safe starting and driving the trucks down to that temperature and if it’s colder, I’ll drive very slow for the first mile or two.