# What's the difference between 5w30 and 5w40?



## sula89 (Apr 23, 2002)

The VW manual said to use 5w40, or 5w30 if 5w40 isn't avaliable, so I have been using Mobil1 5w30 for 20000 miles on my 02 1.8T Jetta. 
I was just thinking if I should change over to 5w40 (Valvoline or Havoline). Does it make that much of a difference? 
Yes, I want my engine to last as long as possible....


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## 4ceFed4 (Apr 3, 2002)

*Re: What's the difference between 5w30 and 5w40? (sula89)*

My choice oil for the 1.8T is Mobil 1 0W-40. It's a little hard to find, but most Advanced Auto Parts and AutoZone stores carry it. 5W-30 is fine if you don't push your car hard, but if you're chipped or run the car hard on occasion, go with a 5W-40 or 0W-40.


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## asphalt_guy (Oct 21, 2003)

*Re: What's the difference between 5w30 and 5w40? (sula89)*

What makes you think you should use 5W40 over 5W30? Where do you live?


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## JettaManDan (Feb 7, 2001)

*Re: What's the difference between 5w30 and 5w40? (asphalt_guy)*

NAPA - Part # 966 - Valvoline Synpower 5w-40 synthetic


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## xxdizankxx (Jun 26, 2003)

*Re: What's the difference between 5w30 and 5w40? (JettaManDan)*

I only use Mobil 1 5w-30. And when I can find the 5w or 0w-40 in 5 quart jugs its on.


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## sula89 (Apr 23, 2002)

*Re: What's the difference between 5w30 and 5w40? (asphalt_guy)*

I live in Oregon, where summer is really hot and winter can get to freezing from time to times.
The reason I think I should use 5w40 is that people tend to use xW40 on turbocharged cars. 
But then I am using the mobil1 5w30 for the past 2 years/20000 miles.
I am thinking of switching to the valvoline 5w40 or havoline 5w40, should I?


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## xxdizankxx (Jun 26, 2003)

Why not switch to Mobil 1 5w40?


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## JoeVeeDubber (Mar 15, 2002)

*Re: What's the difference between 5w30 and 5w40? (sula89)*

I run what the owner's manual tells me to run and the particular brand that I use is LUBRO MOLY. I figure a german car should use german oil







. 
But to answer your question about whats the difference, 5w30 is a thinner oil than 5w40, hence it will provide a thinner coating on the metal in your engine. Engine builder's spec certain oil becuase engines have certain tolerances when they are built. Some have big tolerances, some have small. Most newer car engines have realllly tight tolerances and that's why you see them using really light weight oils, sometimes like 5w20 even. Whereas older engines, like the one in my 1990 VANAGON use 20W50 oil since they have larger tolerances. Back to your situation, I've seen plenty of people run 5w30 with no problems, you might even get a few extra horsepower with the lighter oil since it is easier to pump and slosh around in. Climate is also a factor in picking an oil, you basically want an oil that will cover your climate range, extremes of hot and cold. As for me, I think using 5w40 will prolong the life of my engine, since it is what the engineers spec for the 1.8T. Oil is a touchy issue, do a search on oil and you'll find plenty of topics. 
Edited: for typos, ha, I type too fast...


_Modified by JoeVeeDubber at 10:14 AM 4-20-2004_


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## v double u (Jan 6, 2004)

*Re: What's the difference between 5w30 and 5w40? (JettaManDan)*


_Quote, originally posted by *JettaManDan* »_NAPA - Part # 966 - Valvoline Synpower 5w-40 synthetic 

Same here. http://****************.com/smile/emthup.gif


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## xxdizankxx (Jun 26, 2003)

*Re: What's the difference between 5w30 and 5w40? (JoeVeeDubber)*


_Quote, originally posted by *JoeVeeDubber* »_I run what the owner's manual tells me to run and the particular brand that I use is LUBRO MOLY. I figure a german car should use german oil







. 
But to answer your question about whats the difference, 5w30 is a thinner oil than 5w40, hence it will provide a thinner coating on the metal in your engine. Engine builder's spec certain oil becuase engines have certain tolerances when they are built. Some have big tolerances, some have small. Most newer car engines have realllly tight tolerances and that's why you see them using really light weight oils, sometimes like 5w20 even. Whereas older engines, like the one in my 1990 VANAGON use 20W50 oil since they have larger tolerances. Back to your situation, I've seen plenty of people run 5w30 with no problems, you might even get a few extra horsepower with the lighter oil since it is easier to pump and slosh around in. Climate is also a factor in picking an oil, you basically want an oil that will cover your climate range, extremes of hot and cold. As for me, I think using 5w40 will prolong the life of my engine, since it is what the engineers spec for the 1.8T. Oil is a touchy issue, do a search on oil and you'll find plenty of topics. 
Edited: for typos, ha, I type too fast...

_Modified by JoeVeeDubber at 10:14 AM 4-20-2004_

Damn man, I thought 5w40 was "thinner" than 5w30. I'm still learning I guess.


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## DJKeebler (Dec 6, 2001)

*Re: What's the difference between 5w30 and 5w40? (JoeVeeDubber)*

Ok, so I live in Hawaii where the weather is fairly moderate all year round (hahahahahaha....I live in Hawaii!!! hehe). I used to use 20w-50 is my MkII's because I drove them pretty hard and during the summer it can get pretty hot. 
Since I am now driving a modded 1.8T, is it safe to go back to using 20w-50? Is that going to be too thick during startup? I definitely want my engine to last and have been told that thicker oil sits at the bottom of the engine longer increasing damage to the top components until the oil circulates. With all the extra heat being made by the turbo and higher boost, wouldn't it make sense to use a thicker oil that won't break down so easy?


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## vwinsocal (Mar 15, 2004)

*Re: What's the difference between 5w30 and 5w40? (DJKeebler)*

When I lived in VT i would use a thinner oil in the winter for the cold starts then switch to thicker in the summer...
Now in Cali i use the thick stuff all the time...


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## JoeVeeDubber (Mar 15, 2002)

*Re: What's the difference between 5w30 and 5w40? (DJKeebler)*


_Quote, originally posted by *DJKeebler* »_Ok, so I live in Hawaii where the weather is fairly moderate all year round (hahahahahaha....I live in Hawaii!!! hehe). I used to use 20w-50 is my MkII's because I drove them pretty hard and during the summer it can get pretty hot. 
Since I am now driving a modded 1.8T, is it safe to go back to using 20w-50? Is that going to be too thick during startup? I definitely want my engine to last and have been told that thicker oil sits at the bottom of the engine longer increasing damage to the top components until the oil circulates. With all the extra heat being made by the turbo and higher boost, wouldn't it make sense to use a thicker oil that won't break down so easy?









I would highly recommend you DO NOT use 20w50, that oil is way tooooo thick at cold startup for our tight tolerance engines. Hawaii's weather is warm, but not excessively warm where 5w40 oil is not adequate. If you are overly concerned about the heat I would recommend a 5w50 or maybe a 15w50, but 20w50 is wayyyy too thick at cold startup. While your car may seem like its running smoother, it actually is working harder since the oil is providing a thicker barrier between engine parts. The extra work it does is what creates the smooth feeling. For multigrade oils the first index before the W indicates cold viscosity, the number after the W indicates operating temperature viscosity. 20 is far thicker than 5 and you can tell simply by shaking a bottle of it, also 50 is a bit thicker than 40 and a lot more so than 30. True hotter temps do require a thicker oil, but as long as the oil is in its heat range, it should work fine and provide adequate lubrication. Do a search on google, you might be able to find a chart that displays ambient temperature ranges for different weight motor oils. I know some older car owners manual and some repair manuals also have general sections that have these charts.


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## DJKeebler (Dec 6, 2001)

Thanks JoeVeeDubber......that was a good explanation. I think I'll just stick with the 10W-30 I use now. It's seems like a good choice since like you said, it doesn't get overly hot or cold here. Again.....hahahahahaha! I live in Hawaii!!!
P.S. if anyone ever comes out to visit and wants a tour guide, let me know. I live on Oahu and always willing to show people around.


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## sula89 (Apr 23, 2002)

*Re: (DJKeebler)*

Valvoline 5w40 it is!
I am sooo glad I didn't get flamed


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## sula89 (Apr 23, 2002)

*Re: (sula89)*

Went to NAPA and ordered the Valvoline 5w40. It'll arrive tomorrow morning, pretty nice. It seems like it's on sale, paid just under $24 dollars for a box of 6.


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## AnthonyEbden (Feb 9, 2019)

5w40 oil has a higher viscosity than 5w30 oil. If you live in cold environments, you should use thin grade oil, such as the 5w30. This topic has been presented in a quite complete and useful article on zoniv.com.
https://www.zoniv.com/5w30-vs-5w40/


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## Vegeta Gti (Feb 13, 2003)

This topic has been covered on here exponentially. Get moltul 8100 excess 5w30. Passat large oil filter. Send first oil change to Blackstone, ask for interval information. Go from there 

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