MISTYPED, corrected, you happen to reply faster
At operating temperature, both are the same viscosity (0w30, 10w30) and both will drain to the pan exactly the same right? The 10w30 isn’t going to somehow climb back up magically.
1 Like
ha, right ! this one is out
then the only hard fact is in Noack %%
the shearing argument is in the “everybody has his own opinion” zone
And also without magic, less viscous 0w weight will spread more readily than 10w from the top of the engine on ‘cold’ startup.
1 Like
it will also evaporate more readily, without magic
it is no “ideal oil”, as both 0W… and 10W… are tradeoffs on oil longevity, evaporation, clod start, wear, etc…
Have you looked up the noack test? They heat the oil up to 250C (480F) and blow air over it for an hour. Engine oil normally doesn’t get that hot. Oil is ruined at 480F for any amount of time.
It’s not a room temperature test where oil just evaporates.
1 Like
not during ‘cold’ startup
Certainly not the roughly 100C of the average car engine! And come to think of it, pressure reduces evaporation, so evaporation at 100C in an engine is not the same as at 100C in a pot on my stove.
Oil manufacturers need some comparison point, ideally achievable in a reasonable time, not in years of tests.
BTW, when fuel/air mix burns, temperature is substantially above 250C, so test is quite relevant to real life, for that oil film on the cylinder walls, so oil evaporation takes place at that thin film.
As I pointed before, I specifically discovered Noack % to be quite relevant comparing oil types to use in my Subarus, as it would burn a quart every 2000-2500 miles when I used 5W30 Mobile-1. Once I transitioned to 10W30 Vavoline, it made for much more comfortable under quart in 5000 OCI.
Wow, 166 comments and still going strong. Don’t any of you have cars to get waxed before winter like me? At 17 I took a pledge against defiling (mostly women) so I’ll try not to defile or abuse. Not being an engineer or mechanic, all I do is read the manual and do what it says-mostly. 0-20 synthetic with 5000 mile changes for the Acura, and 5-30 dino with 3000 mile changes for the Pontiac. All my small engines get 5-30 synthetic with yearly or 25 hour changes just like the book says.
Castrol may make a fine oil, I dunno but their marketing reminds me too much of Amway. So I really don’t care what their engineers or marketing folks or dealers say, I give them the same credibility as Amway folks. What I have done has given me engine longevity of 530K, 350K, 240K, 480K, 200K, etc. with the diesel my only engine failure. I may be wasting money but I’ll just keep doing what I have been doing.
1 Like
deleted
stupid minimum 10 character limit
If you look hard, you can find 0W-## oils that are not full synthetics, but generally, that’s mostly true.
Does that old saw about most engine wear occurring at startup still hold true? Engine designs have come a long way since people started saying that.
That old saw still holds mostly true. If a car were started once a day and driven 600 miles every day without being shut off, it would probably not be true , but the most wear per mile would always be the first mile.
Wasn’t it started back when all the oil ran down to the drain pan? Don’t modern engines have valves that prevent that from happening, keeping some oil in the engine and in the parts of the engine where metal touches metal?
Also, don’t modern engines have oil jets under the pistons that provide immediate and continuous oil flow to the cylinder walls?
It seems like most of these types of innovations would significantly cut down on engine wear during startup, unless you’re starting the engine for the first time after an oil change, and it takes a few seconds for the oil light to shut off.
There have been no valves to prevent oil from draining down to the pan in any engine that I have worked on and it’s unlikely that any automotive internal combustion engine has any such devices. But oil remains on friction surfaces for quite some time after shut off.
all modern automotive engines have ‘jets’ that spray oil under the piston onto the cylinder walls and that is a critical wear area where thin oil is a benefit when cold starting. With cold, thick oil the engine can start and run long enough to wipe the cylinder walls dry before oil spray begins.
The oil pumps on cars these days are able to fill the filter and get oil flowing throughout the engine in a short few seconds with the proper oil installed so wear at start up after an oil change is not a problem.
1 Like
Doesn’t your oil filter have one?
“The anti-drain back valve reduces the duration time of the dry or semi-dry friction between the working parts of the engine because by preventing the oil flowing towards the oil pump it speeds up the oil stream getting to the working elements during the start of the engine, especially after a long stop.”*
*http://en.filtron.eu/site.php/site/menu?cat=79
“The anti-drainback valve, included in the filter when required, prevents oil from draining out of the filter. This anti-drainback valve is actually a rubber flap that covers the inside of the inlet holes of the filter. When the oil pump starts pumping oil, the pressure will unseat the flap. The purpose of this valve is to keep the oil filter filled at all times, so when the engine is started there will be an almost instantaneous supply of oil to the engine.”**
That’s on the pressure side of the supply and only meant to stop the filter from emptying. The return side is free to flow from the top (or other areas like piston skirts etc) back to the pan once the supply stops pumping…
Maybe it’s unfortunate that automobile engines aren’t permanently lubricated at the factory like my furnace motor. We wouldn’t have all this arguing over motor oils.
Fortunately, engine oils and engines are much better today than they were 50 years ago. I had terrible problems with sludge blocking the passages to the rocker arms in my 1955 Pontiac and I faithfully changed oil and filter every 2000 miles. I was using Havoline 30 weight as recommended. I bought an almost new 1965 Rambler in 1965. The manual called for an oil and filter every 4000 miles. I changed oil every 2000 miles. At 85000 miles, I had an oil passage to the rocker arm shaft plug up in the block. The shop pulled the head, opened up the passage and put it back together for $42.75.
My only other problem related to oil was with my 1978 Oldsmobile. The engine would carbon up and once a month I would feed a can of Casite Motor Tuneup through the carburetor and then take the car for a fast run on the highway. The manufacturer specified either 10W 30 or 10W 40. I reasoned that heavier was better, so I used 10W 40. I heard on the Cartalk show that, 10W 40 had polymers that could cause carbon build up. I switched to 10W 30 and had no more carbon build up that led to spark rattle. The car consumed no oil between changes with either 10W 40 or 10W 30 in the 33 years I owned the car.
I think it depends on how you define “most engine wear”. Oils are better, manufacturing practices are improved, better metallurgy contributes to overall less wear.
Some oil does remain behind has a film and it suffers more breakdown just after a hot shutdown and it is this oil that has now broken down more that is all there is in the first second or two after startup. But modern oils can tolerate higher temperatures than they used to, especially synthetics, so the breakdown is less.
That is going to contribute to more wear at startup than during normal running. But oil pressure builds up quickly, flushes the residual oil back into the pan quickly and provides fresh lubrication. Also cold engines have larger tolerances so that should help reduce wear.
The rate of wear at start up is going to be at its greatest, but that may not be much higher than normal and it is very short term. My guess is that while the rate of wear is greatest, it is not great enough or last long enough to be the cause of the most wear overall.
Care to quote the section that addresses oil weight? Anytime somebody posts about the ‘Magnusson Moss Act’, my BS warning light goes bright red. Car makes can certainly require you to use a certain weight oil, what if I put gear oil in my crankcase?
And no, modern cars are not ‘tin cans’, they are MUCH safer than they were 20+ years ago.
And why the Amsoil commercial? Crazy expensive, no benefit over normal name brand oils.
1 Like