I live in mid-Florida and want to know about flow rates of different motor oils. At 70 degrees starting ambient temperature how does a 0w-40 wt oil flow compared to a 5w-30 wt oil. Secondly at an engines full operating temperature how does a 0w-40 flow compare to a 5w-30~?
Flow rate comparison.
- Thread starter dwcars
- Start date
No one knows or cares. Oil flow rate is irrelevant. Pump ability is the proper specification and is only important in Winter oil temperatures and Winter ratings i.e the 5 in 5w-xx.
If there is oil in the pan and the oil pump is picking it up, your golden.
If there is oil in the pan and the oil pump is picking it up, your golden.
- Joined
- Aug 15, 2024
- Messages
- 468
at those temps I don’t think it matters much at all. Your car will likely be fine
Ignore the negative nancies.
Try this calculator; Widman was a member for many years but haven't seen him in...seemingly forever.
Should give a good indication in answer to your question.
https://www.widman.biz/English/Calculators/Calculators.html
First, you're asking a question that is not easy to answer because there is such a wide gap in viscosities between SAE J300 grades that without picking two specific examples the outcome can be different. Second, you're getting snarky replies because at 70 F there is no relevant difference and it's still complicated enough to the level that it's possibly not even relevant until you get past sub-zero where the 5W no longer passes CCS and MRV tests.
The root of my concern is that my new car engine shuts off every time I come to a full stop. Why the manufacturers installed this function is beyond me. We all know that most engine wear occurs at starting, and now when I go to town my engine restarts 8 to 10 times where my old car was started only once when I left the house. Nobody can tell me if I can delete this function, and I'm concerned that this feature will cause unnecessary wear over time.
Am I right in my concern about unnecessary wear~?
Am I right in my concern about unnecessary wear~?
The main reason for most wear occurring at startup is due to corrosive wear. https://www.sae.org/publications/technical-papers/content/600190/
The corrosive wear from condensed combustion products is higher because the low temperature allows more of the combustion byproducts to condense. Low engine temperature is more of the enemy than startups in general. Startups are still not ideal even with a warm engine partly because parts are starting from a speed of zero and lubrication generally improves with higher speeds between parts. Also mating parts tend to be physically touching before the startup.
I wouldn’t worry too much but would see if there is a button to turn off the shutdown feature. My friend’s Sentra has a button to turn it off.
The corrosive wear from condensed combustion products is higher because the low temperature allows more of the combustion byproducts to condense. Low engine temperature is more of the enemy than startups in general. Startups are still not ideal even with a warm engine partly because parts are starting from a speed of zero and lubrication generally improves with higher speeds between parts. Also mating parts tend to be physically touching before the startup.
I wouldn’t worry too much but would see if there is a button to turn off the shutdown feature. My friend’s Sentra has a button to turn it off.
You have an oil pump that pumps the oil. In between there is a persistent oil film between moving parts.
As already noted, flow is irrelevant here.
The Widman calculator does not give "flow rates", Nancy.
This. I'm pretty sure the start-stop technology was designed with that concern in mind, because I know in my government vehicle, a 2021 Ford Escape, the start-stop doesn't activate Until the engine reaches a certain temp. What that temp is IDK, because it's before the gauge reaches operation temperature but it doesn't do it after a cold start.
Most cars with start stop function have coated bearings to help prevent wear when there is no oil pressure in those brief moments on startup. They also don’t enable start-stop until the engine is up to temperature.
Regardless, there’s no difference between any oil for this purpose. Auto start stops are done warm and the oil will be near 100 C, so it’s all thin at this temperature. Even a 10W-60 is only 22 cSt at 100 C. This is much thinner than a 0W-20 at 40 C.
Last edited:
Because they want you to buy new starters, batteries and fuel injectors every 35k miles.
You know, because those are the components that see the most wear and tear during frequent on and off usage.
They don't have that nice warm engine oil to keep them coated and protect them from friction wear, like the crankshaft, camshaft, pistons, rings, and intake valve components all do.
It's an actual conspiracy that the automotive manufacturers and the US government have engaged in together that you don't hear about the frequency of replacement of injectors and starters. You hear about batteries all the time, but they have everyone convinced that battery manufacturers are just being cheap with the internals they use, so that is completely overlooked by the masses.
Luckily, most American car buyers aren't as deep thinking and critical of new technology as you are, and you can see right through and past their claims of "It's there to reduce pollution" or "It's to save fuel".
It's only there to make car parts builders more money, because now you're going to have parts that don't get replaced nearly as frequently getting replaced all the time. Or at least 1 time per vehicle. Every vehicle has at least 1 starter. And a gasoline motor can have anywhere between 3 and 16 fuel injectors, depending on if its a vehicle that has GDI and PFI on it. And you always have to replace the whole fuel rail with GDI motors, if you listen to the manufacturers.
HUGE conspiracy.
Of course you're right to be concerned.
Those that tell you not to be are all heavily invested in the stock market, and make millions themselves off of automotive parts company dividend returns. You can't trust their objectivity here. They want you buying replacement parts all the time to make them more money so that they can buy more stocks. Look at the stock threads on this forum, and see what they want you to buy with your hard earned money. Don't trust them, you just can't.
Think about it.
All that starting and stopping kills the fuel injector.
Then that fuel injector kills the driver in the PCM.
So now you need to replace the fuel injector, the GDI rail, and the PCM, all because of your start stop nonsense trying to save the buttercups all along the side of the road here in Freedom Land.
And yes, there are companies that make start stop defeat devices for vehicles, but you never hear of them being advertised, and you know the reason why. Suppression is key.
Don't let them suppress your clearly powerful minds eye that lets you see through all this horse manure that these auto companies and the government are feeding you. I'm so glad you see it all, too.
Just keep thinking, who is this technology REALLY FOR?
Not you, and that's the pure, undistilled truth.