5w 40 to 5w 30?

[TugaSaudade]

My 1.4 4cyl 101hp VW engine is on Shell 5w30
Previously it had Shell 5w40..

Changing to a 5w30 did not make my engine quieter.. did noticed a little more pep and a minor improvement in MPG.

But 5w40 is by far easier and cheaper to find in my dear old europe..

If i had the prices you guys have, i would ALWAYS use 5w30,as long has it meets VW specs (VW50101, 50200 or the better 50400).

 

[AuthorEditor]

I think the high speed, high temperature, driving thing in Europe is just a myth. Sure, Germany has the autobahn, and other countries have fast highways, but they have nothing that compares to say getting on I90 in the U.S. and driving continuously at high speeds across the country for four or five days. Or crossing Texas and Oklahoma in the summer. Northern Europe on average is cooler than much of the U.S. south of New England, but on the other hand much of northern Europe doesn't get as cold as the northern half of the U.S. during the winter (Scandinavia excluded). If anything, they may have more severe drive cycles due to much shorter trips, more stops and starts, smaller higher-revving engines (in general), and fewer miles not letting the engines get up to temperature. I suspect they spec the heavier weights because of that, not high-speed hot driving. However, I still wonder why the typical OCI recommended over there is 7500 miles or 12 months. My guess is that very few people actually reach the 7500 miles in the 12 months, and the yearly change is specified just to make sure the oil does get changed once in awhile. You see lots of 10-20 year old cars in Europe with no rust, in perfect shape, looking like they'll easily go another 10 years.

 

[Audi Junkie]

US 5w30 can work in European cars, even turbos.

In the cold, it can be half as thick as 5w-40.

For an Audi I-5, just pick something that is appropriate for the climate. 40 is not needed except to help a little with consumption or if you have elevated oil temps.

 

[Ronn]

Originally Posted By: Gary Allan
Originally Posted By: Audi Junkie
Heavy 40 weight is to combat high oil temps during sustained high speed driving in Europe.



..or handle potential fuel dilution over an 18month OCI where it may be a 30 grade at change out time.




I have a 09 Chevy Cobalt Turbo with DI and Fuel dilution is a factor. It's also a So Calif car (no real cold temps). I've been thinking of switching over from Pennzoil Ultra 5w30 to Euro 5w40 for the potential dilution factor. Thoughts?

 

[Ronn]

Actually..thinking of mixing 3qts 5w30 with 2 qts 5w40 for starters, since I have some supply of 5w30 on hand.

 

[bigjohn]

Heavy 40 weight is to combat high oil temps during sustained high speed driving in Europe. Newer Euro oils are thick 30 weights and US 30 weights are somewhat thinner. The driving in US does not create the hot oil temps that thins the oil down, so in my experience, starting with a thin or thick 30 produces a fine result.

Going into summer, maybe you'd stick with a 40, but it depends on your car and your driving. Short trip vehicles def can us the thinner oil.

fwiw, I have 5w-20 in Mom's Passat, Downtown Philly.


Generally, I agree with this line of thinking. I like GC 0w30 in the winter here in Colorado and I like Syntec 5w40 in the summer.

On the other hand, I would never run a 20wt in a turbo car. A 3.5 HT/HS is spec....and a 20wt is around a 2.7 or so. I will always stay above 3.5 HT/HS.

 

[Ronn]

Originally Posted By: BigJohn
On the other hand, I would never run a 20wt in a turbo car. A 3.5 HT/HS is spec....and a 20wt is around a 2.7 or so. I will always stay above 3.5 HT/HS.


Well, the 5w30 has HT/HS of 3.2 and 5w40 is 3.68. More reason to switch on my Turbo.

 

[buickman50401]

I've run Mobil 1 0w40, Syntec 5w40, Elf Solaris 5w30 oils in my wifes VW - all meeting vw specs.

I've also run 5w30 Valvoline SynPower in a pinch when the oil needed to be changed and it was too cold to do it so i had a local chain store (Fleet Farm) change it.

No difference in gas mileage in between w40 or w30. No noticeable "freer revving" / more power.

It was louder on the Valvoline and Mobil 1.

Now it just gets Rotella T6 and a Bosch filter and I forget about playing around with different grades. Change it twice a year and be done with it. The different oils and grades didn't make any impact except for the T6. The car is noticeably smoother running and no loss of pep.

 

[CATERHAM]

Originally Posted By: Audi Junkie
Oil temp gauge tells all.


Actually an oil temp gauge just tells oil temps, an oil pressure gauge tells all.

For the OP, yes run the lightest oil the manufacturer recommends.
Could you run an even lighter oil like a 0W-20? Absolutely, as the safety margin with what the mfter recommends is hugh for many reasons as others like Gary have mentioned. With an OP gauge you'd be able to determine how much of a safety margin you have at any given time, but you don't so for your peace of mind stick to what the mfter recommends.

 

[Old Mustang Guy]

German cars generally have crude engines with design deficiencies. A thicker oil tends to mask these inherent disorders (just joking).