Switching grades and brands

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Jan 3, 2020
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I've always heard that it's not a good idea to switch between grades and brands and that you should always stick with what works. From to Scotty Kilmer to mechanics telling me my engine would have serious problems if i went from 5w40 to 10w40 because "clearances are used to 5w40" or whatever. In every car i owned i've switched between brands and grades almost every time it was due for an oil change based on what i have in my stash or what was on sale or simply out of curiosity and never had an oil leak appear or any kind of problem at all. Each time a problem such as a leak appeared is was from sitting for a long time. I don't know what this assumption is based on?
 
Between 40C and 100C the oil viscosity changes by a factor 6... When you go to freezing temps the viscosity changes by a factor 20. When you get near the pumpability limits the oil is a hundred times as viscous then it will be hot. What difference will a few cSt make that a few thousand didn't make when you started.

it's based on a fantasy.
 
have you used the same exact oil fill the factory used???...any issues with your car???...have you used the same brand and API rating etcetera as the original fill???...any issues???...I suspect not

as your engine wears it may need a change in oil viscosity due to that wear or perhaps environmental issues...when I had a 2000 Escalade that sat outside during my ownership, I changed from 5w30 dino oil to 5w30 Mobil 1 full synthetic and even tried Farm and Fleet's house brand full synthetic as I was on call and needed my vehicle to start no matter what the weather...I saw no issues related to oil and neither did the guy who bought it from me who owned it another 7 years...

I think if you follow proper oil fill at the proper time with the right type of oil you should be fine...but it's your car...what do you like?

Bill
 
Grades and brands are often different but what's always consistent is 7000/8000 kilometers OCI, oil level, OEM filter and following the minimum requirements which is ACEA A3/B3. I use anything from the cheapest 15w40 to a 5w40 with the highest specs.
 
Its all just oil, doesnt matter switching anymore then it matters buying different brands of gasolines.
AS far as oil viscosity, I mean, sure you may notice some difference if you change viscosity I mean you are now talking about changing the oil specification that you are using, not brand specific.
 
i dont see a need to change out viscosity.. brand sure.. i don't owe anything to one specific brand oil.. i shop what's best for my pocket. i do prefer napa because they are a local business and like to support that idea and often napa has a great sale on their full synthetic.. around $15 for 5qts. no rebates to worry bout and saves me a trip to wal-mart.. however my other trusted oil is supertech. keep it simple 5w40 will give great all round protection.. if you develop leaks there is something else going on.
 
It just depends on the motor. Grandma's 3800 Buick can probably be ran with ant brand and anything that's not thinner than xw-30, whereas a Mercedes AMG V12 or V8 twin turbo may be designed specifically for 1 oil. Everything else in between in mass production with variable valve timing, cylinder shutdown, hybrid engines, turbo, and supercharged will have different behaviors with different oils than specified, or almost no difference at all other than oil pressure. Only time I think it really matters is below 0 degrees.

I did see a 5.7 Hemi Charger a few days ago that threw a code for incorrect oil viscosity, but then other people never have issues running something thicker than 5w-20. Only way we can really know if it's bad is if you experiment. It may take hundreds of thousands of miles for an engine to suffer more damage or less damage with a different oil viscosity, or results may be immediate.
 
I've always heard that it's not a good idea to switch between grades and brands and that you should always stick with what works. From to Scotty Kilmer to mechanics telling me my engine would have serious problems if i went from 5w40 to 10w40 because "clearances are used to 5w40" or whatever. In every car i owned i've switched between brands and grades almost every time it was due for an oil change based on what i have in my stash or what was on sale or simply out of curiosity and never had an oil leak appear or any kind of problem at all. Each time a problem such as a leak appeared is was from sitting for a long time. I don't know what this assumption is based on?
Have you kept a vehicle long enough to know? I'd say 130k+ miles all of them having been changing it up frequently.
 
You stated that you have switched between brands and grades on every car you have owned when an oil change was due and you haven’t had any problems that you mention. That should ease your mind and tell you something
 
Brands? No problem. Grades/viscosity? Nope. I know Project Farm did a video about that, but I'm not going to do it. For a top off, if your car uses 5w30 and you use 1/2 qrt. of 5w20, will it hurt anything? Probably not. Stick with the proper grade. Any API full synth from WM with a good filter and OCI is more important. PP, QS, Havoline, Castrol, whatever.
 
typical BS as todays oils with the same approvals are quite similar!! blanket recommendations-on oil cap are just that + seldom take your local temps into play as florida + minnesota are QUITE different + IMO the thinner xxw20 oils put a very little mpg gain over longer engine life + protection, thank you our government!! OLM are BS as well + extending changes as well as skipping the filter is penny wise + dollar foolish as a DIY 5QT synthetic oil + good filter is about $30
 
You should not have issues. Switching from a 10W-40 to 5W-40 shouldn’t have an impact as they are the same viscosity with a different winter rating so it’s just the winter flow that is different. You haven’t had any issues so I think what the mechanics have told you is wrong.
 
I've always heard that it's not a good idea to switch between grades and brands and that you should always stick with what works. From to Scotty Kilmer to mechanics telling me my engine would have serious problems if i went from 5w40 to 10w40 because "clearances are used to 5w40" or whatever. In every car i owned i've switched between brands and grades almost every time it was due for an oil change based on what i have in my stash or what was on sale or simply out of curiosity and never had an oil leak appear or any kind of problem at all. Each time a problem such as a leak appeared is was from sitting for a long time. I don't know what this assumption is based on?
Well don't confuse my Toyota its had a different brand oil in it every OCI in the last three years. 5w-20, 5w-30 and 10w-30 it is getting pretty bad though it almost used a half a quart of the 5w-20 in a 6K mile change OCI I'm so worried about this I just don't know what to do. :rolleyes:
 
Kilmer is an idiot.

For most all engines, use the grade recommended by the manufacturer. In almost every case, that is best. Changing brands is pure wife's tale lore garbage, with roots in the lousy petroleum based engine oils of the 1970's and back.

The "clearance" stuff you hear and read is most all bull kraporoni. NOW will you have a problem running say 0W-30 in a 0W-20 engine? No. 5W-40 v. 10W-40? 5W-40 likely a better constructed oil in the first place, but the 100°C viscosity of both better be in the same range.
 
Have you kept a vehicle long enough to know? I'd say 130k+ miles all of them having been changing it up frequently.
I have one car with 500 000 kilometers and for 400 000 it had this diet and no sludge, no wear, no leak.
i dont see a need to change out viscosity.. brand sure.. i don't owe anything to one specific brand oil.. i shop what's best for my pocket. i do prefer napa because they are a local business and like to support that idea and often napa has a great sale on their full synthetic.. around $15 for 5qts. no rebates to worry bout and saves me a trip to wal-mart.. however my other trusted oil is supertech. keep it simple 5w40 will give great all round protection.. if you develop leaks there is something else going on.
The oily reason i change grades is because of the price. Unlike in the US where you can get a 5w30 in both dino and synth, here dino is 15w40, semi synthetic is 10w40 and 5w40 is synthetic and 5w30 are only synthetics and are usually low saps or low HTHS oils.
 
I wouldn't run 20w50 (or even 10w40) in an engine spec'd for 0w20 (and vice-versa) or any similar extremes... I hope that would be obvious to most BITOGers. Changing brands is irrelevant. Just use an oil that meets the spec, keep a reasonable service interval, consider your usage and ambient conditions (severe service or not) and you will be fine. I agree that most normal drivers should use the oil spec in the owner's manual. It's pretty simple.
 
I have never, ever had oil related issues with an engine.
Isn't that the truth.

You guys worry waaaaaaaaay too much on these things in life that don't matter 😂

I was using Schaeffer's oil in the Ford Escape for the past 4 years. The last oil change I not only used Royal Purple HMX I also went up from 5w20 to 5w30 !!

Stop sweating the small stuff!
 
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