Using 5w20 in motor spec'd for 5w30?

hal

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Have seen lots of people running 5w30 in 5w20-spec'd cars, but not the opposite. Would this increase wearsurface metals in oil over time? Would it help improve gas mileage? Would the engine be more happy to rev? What would be the costs versus benefits, if any? Just kind of curious, that's all...Thanks for your input!
 
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In most cars, it won't do any harm, as most 30-weight oils shear down to a high 20-weight anyways.
 

hal

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no engine in particular, just a curious question. Cars I could potentially do this in would be a Mazda F2-sohc engine, Honda d16a6 sohc, or volvo 2.4L I5. Not really considering doing it at this point, as I'm just seeking theories.
 
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A lot of engines were originally spec'd for 5W/30 and then were changed to 5W/20. The Honda 4 bangers were one of the engines that this happened to.
 
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 Originally Posted By: hal
Have seen lots of people running 5w30 in 5w20-spec'd cars, but not the opposite. Would this increase wearsurface metals in oil over time? Would it help improve gas mileage? Would the engine be more happy to rev? What would be the costs versus benefits, if any? Just kind of curious, that's all...Thanks for your input!
My 93 Ford 3.0L [171,000 miles] was back spec'd to 5W20 from 5W30. I'm running 5W20 for 2 OCI's and will be changing it again shortly. I'm using slightly less oil with the 5w20, but that could be the effects of the 2 A-Rx clean rinse phases I completed. No strange noises, and the engine has not self destructed at the time of this being written. JMO
 
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 Originally Posted By: hal
Have seen lots of people running 5w30 in 5w20-spec'd cars, but not the opposite. Would this increase wearsurface metals in oil over time? Would it help improve gas mileage? Would the engine be more happy to rev? What would be the costs versus benefits, if any? Just kind of curious, that's all...Thanks for your input!
hal, I run M1 synthetic 5W-30 in my 01' Durango V-8 and want to try some 5W-20 to see if I increase my MPG. Currently I can get about 22.2MPG on a long trip. I'm even considering trying the 0W-30 weight. Durango
 
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My local Honda dealership put in 5w-20 in my '00 Honda Odyssey that is spec'd for 5w-30. I noticed that on my reciept when I paid for my oil change. I asked the service manager about that and he had the oil drained and they put in 5w-30. He apologized profusely (spelling?) about it. I just said, thanks. I didn't complain since the service manager corrected the problem with minimal fuss.
 
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 Originally Posted By: hal
Have seen lots of people running 5w30 in 5w20-spec'd cars, but not the opposite. Would this increase wearsurface metals in oil over time? Would it help improve gas mileage? Would the engine be more happy to rev? What would be the costs versus benefits, if any? Just kind of curious, that's all...Thanks for your input!
Wont hurt a thing.
 
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My 1994 3.1 litre (Chevy) was spec'd for 5W30, I have completed 250K miles of severe towing duty (4,880 lbs) using 0W20 with no problems, no oil consumption and no leaks - the valve covers have never been off. I switched everything to 0W20 years ago (Mobil 1), all of the cars were spec's for it, all are nearing 300K with no perceivable wear. The only thing I notice for sure is that the cars always start at - 40 degrees when skiing in the mountains..... often there is an entire parking lot full of cars that does not!
 
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 Originally Posted By: fsskier
My 1994 3.1 litre (Chevy) was spec'd for 5W30, I have completed 250K miles of severe towing duty (4,880 lbs)
You pull 5000lbs with a minivan?!?! Don't you think that's a little dangerous?
 
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i play it safe, blend 5w20 conventional with 5w30 synthetic. you get an excellent oil. my engines all love it mitsubishi 1.5l 12v, subaru 2.5 NA, subaru 2.2 NA, dodge 3.7 v6, GM 3.4 v6.
 

hal

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 Originally Posted By: scoobie
i play it safe, blend 5w20 conventional with 5w30 synthetic. you get an excellent oil. my engines all love it mitsubishi 1.5l 12v, subaru 2.5 NA, subaru 2.2 NA, dodge 3.7 v6, GM 3.4 v6.
this sounds like a good idea
 
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 Originally Posted By: DragRace
 Originally Posted By: hal
Have seen lots of people running 5w30 in 5w20-spec'd cars, but not the opposite. Would this increase wearsurface metals in oil over time? Would it help improve gas mileage? Would the engine be more happy to rev? What would be the costs versus benefits, if any? Just kind of curious, that's all...Thanks for your input!
Wont hurt a thing.
The body will rot out long before the motor dies.
 
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 Originally Posted By: scoobie
i play it safe, blend 5w20 conventional with 5w30 synthetic. you get an excellent oil. my engines all love it mitsubishi 1.5l 12v, subaru 2.5 NA, subaru 2.2 NA, dodge 3.7 v6, GM 3.4 v6.
I've always wondered what it means when people say "my engine loves it". By not blowing up, does that mean it loves it?
 
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I run 5W-20 in my 96 Crown Victoria that was specced for 5W-30. The engine loves the thin stuff. It's quiet, and revs more freely. Doesn't feel bogged down. I'm also running 5W-20 in my dads car, a 93 Oldsmobile Cutlass Supreme SL with a quad cam V6. Switching it to a better filter (Wix made AC Delco) and a thinner oil made that engine purr.
 

OVERKILL

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 Originally Posted By: BuickGN
 Originally Posted By: scoobie
i play it safe, blend 5w20 conventional with 5w30 synthetic. you get an excellent oil. my engines all love it mitsubishi 1.5l 12v, subaru 2.5 NA, subaru 2.2 NA, dodge 3.7 v6, GM 3.4 v6.
I've always wondered what it means when people say "my engine loves it". By not blowing up, does that mean it loves it?
ROFLCOPTER!!!!!
 
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 Originally Posted By: Durango
hal, I run M1 synthetic 5W-30 in my 01' Durango V-8 and want to try some 5W-20 to see if I increase my MPG. Currently I can get about 22.2MPG on a long trip. I'm even considering trying the 0W-30 weight. Durango
You'd probably actually see more of a gainf rom a 5W-20 synthetic than you would from a 0W-30. The 5W-20 should be thinner at pretty much all temperatures.
 
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