5w 40 to 5w 30?

Status
Not open for further replies.
M

marcre

Joined
Jul 22, 2005
Messages
287
Location
Timonium, MD
I'll admit, I am not the most knowledgeable when it comes to weights of oil.

My Jetta calls for 5w 40 and it can also use 5w 30. Would it be better to use the 30? Would there be any advantages? Would there be any disadvantages?

Would the engine even notice the difference?

I guess the reason I ask is I see so much talk about XW 20. With other manufacturers calling for a thinner oil and mine is calling for something so thick(or maybe better said, something thicker). I'm curious as to why VW specs something thicker when most have spec'd a thinner oil.
 
German engines are designed that way, I guess. If the maker calls for xx40, there must be a reason.
 
Originally Posted By: shrooms
German engines are designed that way, I guess. If the maker calls for xx40, there must be a reason.


Thanks for the reply. I figured that, just curious. Are the engines not as tight? I guess I'm looking for the reason.
 
Well, the common advantage of the 5w40 is that it is typically an HDEO. If you have reason to run an HDEO - like a stouter add-pack and possibly a longer OCI - then go for it. I use them (5w40's) because I can buy 1 grade of oil and use it in everything.

Obviously this choice isn't the best for everyone, but it works for me.

I'm sure your Jetta would be fine either way, but the 40 might be better in a southern hotter climate than a 30-weight - at least in theory, but i'm old-fashioned.

Would the engine notice? Probably not, at least not in my experience. Funny though, some of the Xw20's actually claim to be compatible in engines that require a 5w30 (Mobil 1 I believe - but could be wrong). I personally like something a little heavier than a 20 - but that's just me.

Rob
 
Last edited:
I have 5w 30 in my '97 Jetta and the engine seems noisier than normal to me.

I will be going back to 5w 40 at the next oil change, mainly to see if the engine noise is all in my head.

My car has 92,000 miles on it and doesn't use oil.
 
Originally Posted By: Scooter_man
Well, the common advantage of the 5w40 is that it is typically an HDEO. If you have reason to run an HDEO - like a stouter add-pack and possibly a longer OCI - then go for it. I use them (5w40's) because I can buy 1 grade of oil and use it in everything.

Obviously this choice isn't the best for everyone, but it works for me.

I'm sure your Jetta would be fine either way, but the 40 might be better in a southern hotter climate than a 30-weight - at least in theory, but i'm old-fashioned.

Would the engine notice? Probably not, at least not in my experience. Funny though, some of the Xw20's actually claim to be compatible in engines that require a 5w30 (Mobil 1 I believe - but could be wrong). I personally like something a little heavier than a 20 - but that's just me.

Rob


Good stuff, thanks. Why would a 40 be better in a hotter climate? I would have thought the opposite, but I admit some things I do not understand at this point.
 
Originally Posted By: duaneb9729
I have 5w 30 in my '97 Jetta and the engine seems noisier than normal to me.

I will be going back to 5w 40 at the next oil change, mainly to see if the engine noise is all in my head.

My car has 92,000 miles on it and doesn't use oil.


Interesting. My engine isn't crazy loud. But, this VW is the loudest engine I think I've ever owned. That was one reason for me bringing up this whole thing. I was wondering if the 30 would make it quieter.

Maybe VW's are just louder engines.
 
Originally Posted By: marcre
Thanks for the reply. I figured that, just curious. Are the engines not as tight? I guess I'm looking for the reason.


From what I've gleaned here, there are a couple reasons. My Audi is the same way, specifying up to 20w-50 if the temperatures are right.

In Europe, they tend to have longer OCIs. A thicker oil and/or an HDEO can be helpful there. Also, German highway speeds tend to be a little more spirited than they are in North America, and a thicker oil might be more suitable.
 
Originally Posted By: Maritime Storm
You didn't mention which engine this was for. If it's turbo or/and Diesel stick with the 5W40.


My bad, I meant to. It's the 2.5 Gas 5cyl. No turbo, although that would be fun.
 
You car is designed as a package. While not exotic, it has the same engineering DNA in it that most European vehicles do. They spec a fluid that works best with that in mind.

The North American market is somewhat unique. We pay much lower prices for lubricants and tend to use shorter intervals.

It's somewhat harder to wrap around in conceptual view ..at least for us. 5w-40's are spec'd in those chassis, over that duration, over the full spectrum of potential usage. That produces an "envelope" of functionality over the projected life span of the chassis. If you're not reaching the margins on that envelope (most of us do not even come close) then you don't "need" to use the typically spec'd fluid since you're never demanding its full performance (read as "performance over time").

You're managing the process variable over time. Shorten the time or compress the variable.. and in many cases you have more latitude in suitable fluids.

I'm struggling to communicate this. If you bought a machine ..any machine ..and the manufacturer spec'd xyz lube to be changed at 250hours after an initial change of 100hours, you would do it and not look back ..without question.

In North America we tend to wrap it around the end users who are diverse and archaic. It would be like a machine manufacturer interviewing the company and seeing how they "felt" about their machine and how they were likely to maintain it ..and what compromises they could incorporate into the design from a maintenance perspective.
 
Meet the specifications required, and worry less about the viscosity. I would try to grab a typical viscosity versus temperature chart and figure it out from there based upon what youre anticipating.

So Id follow spec, which is likely 502.00 and A3, but check your OM. Only UOA or some other analytical technique can really give additional insight...
 
I have no issue with sticking to what is required, and in fact, I will. Just curious as to why it is required and what a 30 would do and if there would be a benefit. Doesn't seem like there would be. So 5w 40 it is.

Just trying to get a better grasp of the different oils and why some require one and others require something else.
 
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.
 
Originally Posted By: Gary Allan
...
In North America we tend to wrap it around the end users who are diverse and archaic. It would be like a machine manufacturer interviewing the company and seeing how they "felt" about their machine and how they were likely to maintain it ..and what compromises they could incorporate into the design from a maintenance perspective.


AND overlay upon this that we have an especially aggressive quick change industry that has done a marvelous job propagandizing the public to believe in the ancient, virtually needless 3 month/3k mile OCI, irrespective of what their engines really need, and what their modern oils can really do.
 
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.

Originally Posted By: ekpolk
Originally Posted By: Gary Allan
...
In North America we tend to wrap it around the end users who are diverse and archaic. It would be like a machine manufacturer interviewing the company and seeing how they "felt" about their machine and how they were likely to maintain it ..and what compromises they could incorporate into the design from a maintenance perspective.


AND overlay upon this that we have an especially aggressive quick change industry that has done a marvelous job propagandizing the public to believe in the ancient, virtually needless 3 month/3k mile OCI, irrespective of what their engines really need, and what their modern oils can really do.


It's all part of our consumption model. I'm still convinced that our somewhat unique massive fuel consumption requires cheap lubricants and shorter OCI's just to "get them out of the way".

I think the producer end of the market is preparing for that model to change.
 
Do you have a turbo? do you race around and get the oil super hot with a NA engine? then use 5-40.
For normal use, the 5-30 will be great.
 
I drive my 2006 A4 2.0TFSI
I live in Indonesia which everyday is summer day
I ran some Elf excellium 5w-30 API SM/GF4 and having no trouble,
then I ran Petronas Syntium 3000 LL 5w-30 which is VW 502 approved, both with 4000 miles OCI, quite simillar performance with previous GF4 5w30 oil. also no trouble,
Then I read many UOA from VW/Audi engine that Redline 5w40 perform best for this engine, so I switch to this oil
but fuel economy is dropping +- 10 %...
so Im hoping that this oil will prolonged this engine life beside sacrificing the "fuel economy"
 
Status
Not open for further replies.

Similar threads

Z
Should I run 5w-30 or 5w-40 or.....?
2
Replies
26
Views
1K
ChrisD46
Redhawk454
0w-30/5w-30 in a 2024 crosstrek and subaru timing chains
3 4 5
Replies
89
Views
10K
Redhawk454
S
API versus Euro oil, for the same engine
Replies
17
Views
1K
KCJeep
V
Why are most C3 xW-40 oils, 5W-40 and not 0W-40?
Replies
4
Views
1K
buster
013fx37
Seeking advice for 2013 fx37 oil
Replies
6
Views
500
ka9mnx
Back
Top