Hi, all. I am new to the forum,yet I have read A LOT of the posts here by various posters and A.E. Haas in particular. In Hass' Motor Oil lessons 101 thru 201 http://www.bobistheoilguy.com/aehaas/ his general opinion is overall thinner viscosities are what cars will thrive on - always looking to lower that cold start viscosity and even the hot engine temp viscosity. That may all valid and functional, yet I am very intrigued by the first hand accounts of an intelligent poster named Beelzebob, whom I found on a Google search within a Cadillac forum. His insights of 5W (or even 0W) vs 10W are very interesting and well-grounded yet quite counter to A.E. Hass' contentions. Please have a read and tell me what you think...
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Question: "There is little to no advantage cold with the 5W30 oil" Are you kidding? Maybe when I said "cold start" you thought I meant that the the car had been sitting over a few hours reguardless of outside temperature. What I'm saying is that a 5W30 oil is better for colder climates. 5W30 flows much faster to vital areas of an engine when its 0 - 10 F (current temperatures where I live) then a 10W30 ever could. Just compare the pour points of a conventional 5W30 to a 10W30. Or just stick a bottle of 5W30 and 10W30 outside in the snow over night (like when its 0 - 10 F) and then compare how each oil flows.
Beelzebob: Actually, I have done all of what you suggest...and I have done it at temps down to -40 in our cold weather testing.
Granted, the 5W30 will flow a little quicker....but overall not enough to make a difference. Don't be mislead by the oil marketing and the scare stories of "cold starts ruining your engine" and the "engine running dry until oil gets to it". There is residual oil in all the bearings and at all the interfaces where oil is required that stays there for days/weeks. The bearings on the rods and crank mains do not require oil pressure to function. A hydrodynamic bearing makes it's own pressure as the load move the journal around inside the bearing...much like an eccentric and the rotation of the journal shearing the oil and creating the oil pressure inside the bearing that supports the load. The bearing will run for minutes at light load with just the residual oil in it.
The only real test here is to put a very accurate, non-damped oil pressure gauge on the engine with a 3/8 copper line to it so it is RESPONSIVE and do cold starts. The oil pressure comes up so quick with either a 5W30 or the 10W30 that there is practically no difference...and...practically speaking, as far a the bearing is concerned, there is little or no difference to the engine.
There are two things that you have to consider. The engine is a series of internal oil leaks that the oil pump pumps oil to....the amount of "leakage" at all the bearings and such is what causes the loss of oil pressure. The pressure is determined, then, by the oil pump capacity (or what it is pumping) and the "leaks" on the engine end. The 5 weight oil will pump a little quicker but more of it is required as the "leaks" will let more 5 thru than 10. The 10 weight oil pumps up a little slower...but...there is not much of it required to build and maintain oil pressure as , for the same "leaks", less 10 weight will go thru the sytem. So...the 10W30 is not nearly as "bad" as you think.
Your temps of 0 are not bad. Our cold start testing is to start after an overnight soak of -20F and immediately go to 5000 RPM to check the oil pressure control valve agianst overpressurization of the sytem... Test engines go thru hundreds of cycles of this without a lube problem.
I have seen engine bearings from engines cold started on an abusive driving schedule in Kapuskasing, Ontario (-40 regularily all winter long at night) and there is no discernable difference between the 10W30 and the 5W30 oils. The factors that the automotive engine engineers consider with the winter oil recommendations is the cranking speed improvement with the 5W30 and the fuel economy improvement with the 5W30. Period.
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Question: "There is little to no advantage cold with the 5W30 oil" Are you kidding? Maybe when I said "cold start" you thought I meant that the the car had been sitting over a few hours reguardless of outside temperature. What I'm saying is that a 5W30 oil is better for colder climates. 5W30 flows much faster to vital areas of an engine when its 0 - 10 F (current temperatures where I live) then a 10W30 ever could. Just compare the pour points of a conventional 5W30 to a 10W30. Or just stick a bottle of 5W30 and 10W30 outside in the snow over night (like when its 0 - 10 F) and then compare how each oil flows.
Beelzebob: Actually, I have done all of what you suggest...and I have done it at temps down to -40 in our cold weather testing.
Granted, the 5W30 will flow a little quicker....but overall not enough to make a difference. Don't be mislead by the oil marketing and the scare stories of "cold starts ruining your engine" and the "engine running dry until oil gets to it". There is residual oil in all the bearings and at all the interfaces where oil is required that stays there for days/weeks. The bearings on the rods and crank mains do not require oil pressure to function. A hydrodynamic bearing makes it's own pressure as the load move the journal around inside the bearing...much like an eccentric and the rotation of the journal shearing the oil and creating the oil pressure inside the bearing that supports the load. The bearing will run for minutes at light load with just the residual oil in it.
The only real test here is to put a very accurate, non-damped oil pressure gauge on the engine with a 3/8 copper line to it so it is RESPONSIVE and do cold starts. The oil pressure comes up so quick with either a 5W30 or the 10W30 that there is practically no difference...and...practically speaking, as far a the bearing is concerned, there is little or no difference to the engine.
There are two things that you have to consider. The engine is a series of internal oil leaks that the oil pump pumps oil to....the amount of "leakage" at all the bearings and such is what causes the loss of oil pressure. The pressure is determined, then, by the oil pump capacity (or what it is pumping) and the "leaks" on the engine end. The 5 weight oil will pump a little quicker but more of it is required as the "leaks" will let more 5 thru than 10. The 10 weight oil pumps up a little slower...but...there is not much of it required to build and maintain oil pressure as , for the same "leaks", less 10 weight will go thru the sytem. So...the 10W30 is not nearly as "bad" as you think.
Your temps of 0 are not bad. Our cold start testing is to start after an overnight soak of -20F and immediately go to 5000 RPM to check the oil pressure control valve agianst overpressurization of the sytem... Test engines go thru hundreds of cycles of this without a lube problem.
I have seen engine bearings from engines cold started on an abusive driving schedule in Kapuskasing, Ontario (-40 regularily all winter long at night) and there is no discernable difference between the 10W30 and the 5W30 oils. The factors that the automotive engine engineers consider with the winter oil recommendations is the cranking speed improvement with the 5W30 and the fuel economy improvement with the 5W30. Period.
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