5W-20 vs. 5W-30

[Zenmervolt]

Originally posted by: ThePresence

Originally posted by: Zenmervolt

Originally posted by: chucky2
You'll probably even notice a little bit quicker rev'ing of the engine.

You may indeed notice this. It won't actually be there in reality, but it's possible that people will notice it. After all, some people notice improvement from fuel line magnets.

5w20 and 5w30 are essentially interchangeable. It's not possible for 5w30 to cause problems in engines that specify 5w20. 5w20 can also be more difficult to find at a local auto parts store (though this has improved significantly so it shouldn't be an issue any longer), so if you can't find 5w20, 5w30 will be perfectly fine.

As always, I do not recommend mixing two viscosities.

ZV

If they're interchangeable why would it be a problem to mix the two?

Like Pac said, just a "better safe than sorry".

Comes more from the days when the agents in oil that help change the viscosity may not be the same between two different viscosities of multiweight oil. Also from the days of straight-weight oils that didn't change viscosity rating with temperature.

Now-a-days the recommendation is more to make it easier for an owner to know what's actually in the engine rather than guessing something like, "Well, I filled it with 5w20, then topped it off at 1,000 miles with an old bottle of straight 30 weight from my garage, then at 2,000 miles I topped it off again with a bottle of 10w30...".

ZV

 

[Riverhound777]

My Mazda 3 manual says 5w-20, I use 5w-30. The reason being because that is what Costco sells. I buy the box of Mobile 1 syn and have had no problems for 44k miles so far.

 

[DOTC]

Hate to ask this, but my 1997 civic calls for 5w-30 and I've been using 10w-30. I've always been told to use 10w-30 for Houston, tx weather.. not doing any damage am I?

 

[iamwiz82]

Originally posted by: Pacfanweb

Originally posted by: Thump553
Suppose something goes wrong with the engine because of the oil-who would you rather look to pay for replacing the engine, Honda or your local mechanic?

I also strongly suspect the cost of the oil to the mechanic factors in a lot to his choice.

Even if the oils are practically identical, to me it's a no-brainer decision-put in what the manual says to.

If something fails, it's a mechanical failure, and the only two ways oil can even be related to one is if you stray too far away from the recommended oil for your car, or if you don't change it often enough.

So is it bad to put in 90w140? 😀

 

[SoulAssassin]

Originally posted by: iamwiz82

Originally posted by: Pacfanweb

Originally posted by: Thump553
Suppose something goes wrong with the engine because of the oil-who would you rather look to pay for replacing the engine, Honda or your local mechanic?

I also strongly suspect the cost of the oil to the mechanic factors in a lot to his choice.

Even if the oils are practically identical, to me it's a no-brainer decision-put in what the manual says to.

If something fails, it's a mechanical failure, and the only two ways oil can even be related to one is if you stray too far away from the recommended oil for your car, or if you don't change it often enough.

So is it bad to put in 90w140? 😀

Not if you're putting it in your diff...in the engine...not so much. I think it would be a good idea for a beater junkyard car just to see what would happen.

 

[woodie1]

Originally posted by: iamwiz82

Originally posted by: Pacfanweb

Originally posted by: Thump553
Suppose something goes wrong with the engine because of the oil-who would you rather look to pay for replacing the engine, Honda or your local mechanic?

I also strongly suspect the cost of the oil to the mechanic factors in a lot to his choice.

Even if the oils are practically identical, to me it's a no-brainer decision-put in what the manual says to.

If something fails, it's a mechanical failure, and the only two ways oil can even be related to one is if you stray too far away from the recommended oil for your car, or if you don't change it often enough.

So is it bad to put in 90w140? 😀

90w140 would work fine since your starter probably wouldn't turn the engine over. 😉

 

[Zenmervolt]

Originally posted by: DOTC
Hate to ask this, but my 1997 civic calls for 5w-30 and I've been using 10w-30. I've always been told to use 10w-30 for Houston, tx weather.. not doing any damage am I?

You're probably fine. Houston doesn't get cold enough for the thicker cold weight of 10w30 to be an issue. If you were in Maine during the winter, you'd be causing more wear during cold starts, but since you aren't going to be getting below freezing in Houston it won't realistically be an issue.

ZV

 

[Pacfanweb]

Originally posted by: iamwiz82

Originally posted by: Pacfanweb

Originally posted by: Thump553
Suppose something goes wrong with the engine because of the oil-who would you rather look to pay for replacing the engine, Honda or your local mechanic?

I also strongly suspect the cost of the oil to the mechanic factors in a lot to his choice.

Even if the oils are practically identical, to me it's a no-brainer decision-put in what the manual says to.

If something fails, it's a mechanical failure, and the only two ways oil can even be related to one is if you stray too far away from the recommended oil for your car, or if you don't change it often enough.

So is it bad to put in 90w140? 😀

Sad to say, I've seen that done to a high-mileage oil burner at a used car lot just to get it sold.

 

[Thump553]

Originally posted by: Marlin1975

Originally posted by: Thump553
Suppose something goes wrong with the engine because of the oil-who would you rather look to pay for replacing the engine, Honda or your local mechanic?

I also strongly suspect the cost of the oil to the mechanic factors in a lot to his choice.

Even if the oils are practically identical, to me it's a no-brainer decision-put in what the manual says to.

Please tell me how 5w30 would cause a motor that came with 5w20 to go bad?


Are some of you that dumb? There is little to no diff. in 5w20 and 5w30. Its only done for CAFE standards in the US so they don;t have to pay as much on fees/taxs/etc... tied to CAFE. Same cars/engines that call for 5w20 in the US get 5w30 around the world.

I'm not an automotive engineer, or an engineer of any type. But where the manufacturer specifically says use XXX and Joe Blow mechanic says YYY is just as good, I'm going with XXX every time-especially when the cost difference is zero (at the mechanic) or a dollar or two (home oil change). Its simply not worth the hassle and risk.

 

[Vette73]

Originally posted by: Thump553

Originally posted by: Marlin1975

Originally posted by: Thump553
Suppose something goes wrong with the engine because of the oil-who would you rather look to pay for replacing the engine, Honda or your local mechanic?

I also strongly suspect the cost of the oil to the mechanic factors in a lot to his choice.

Even if the oils are practically identical, to me it's a no-brainer decision-put in what the manual says to.

Please tell me how 5w30 would cause a motor that came with 5w20 to go bad?


Are some of you that dumb? There is little to no diff. in 5w20 and 5w30. Its only done for CAFE standards in the US so they don;t have to pay as much on fees/taxs/etc... tied to CAFE. Same cars/engines that call for 5w20 in the US get 5w30 around the world.

I'm not an automotive engineer, or an engineer of any type. But where the manufacturer specifically says use XXX and Joe Blow mechanic says YYY is just as good, I'm going with XXX every time-especially when the cost difference is zero (at the mechanic) or a dollar or two (home oil change). Its simply not worth the hassle and risk.

Please stop posting, esp in the garage section. Your posts show how little you know about cars, let alone engineering.

 

[chucky2]

The main point here is that there's no point to run xW-30 in vehicles spec'd for xW-20 unless that vehicle is going to be in a high fuel dilute situation, or, you suspect water ingress is going to occur/is occurring. Both of those situations are going to cause a drop in the viscosity of the oil, including the HT/HS number which may - if the appropriate load is experienced - cause boundary lubrication to fail which means barrier lubrication will be all that's left....and that's not really desirable.

In other words, for the vast vast majority of the engines out there that are spec'd to run xW-20, we should be using xW-20.

Running xW-30 will cause no harm, but it's not going to do a d@mn thing for the life of the engines.

Chuck

 

[Muadib]

I also have a 2004 TL, and I'm pretty sure the manual states you can use 5W-30, but go back to 5W-20 on your next change.

When I first got the car, nobody in my area had the 5W-20 in stock, not even the dealer. I had no choice but to go with 5W-30 on what was my second oil change. I checked with the dealer to make sure it was ok, and he gave me the thumbs up. He mentioned that my mpg might drop, but that there would be no warranty issues.

Sure enough, my mpg dropped 2 mpg during the time I had the 5W-30 in the car. It was no big deal then, because gas was about 50% cheaper than it is now. I went back to 5W-20, and the mpg loss returned to where it was. I've used 5W-20 since, because it's everywhere now.

I should mention that I use Mobil 1 now, but used Castrol Syntec back in 2004, because they had 5W-20 then and Mobil didn't. I use synthetic because the car says it needs new oil about every 8-9k, and I don't trust keeping dino oil for that long.

 

[Savij]

Damn, all you other Acura/Honda owners. Every time I take my RSX in, i have to watch them so that they don't put the 20 in since the recommended is 30 for me. 😛