Why 5w-40 not listed in 350z manual?

[legar]

Hi,

I have a stock 2004 350z Touring as a daily. I'll bring the car to a drift track to learn the basics. I want to change the oil before I go. According to the user manual, 5W-30 is preferred but 10w-30/40 can also be used if ambient temperature is above -18C. Where I live, it has been hovering around +35C which is awfully hot. So I was thinking of using Amsoil Signature 5W-40 (instead of Amsoil Premium Protection 10W-40). But I'm curious why the manual mentions 10W-40 specifically but NOT 5W-40? For a daily driven 350z, spirited driving once a week and track racing/drifting around once or twice a year, what would you do?

 

[Hall]

I don't think 5W-40 was a common "car" oil ~20 years ago (it was for diesels, if I'm not mistaken). Here's the secret though: It says you can use 5W and it says you can use -40, so you can 100% safely use 5W-40. The numbers before and after the "-" aren't hard-linked.

 

[kschachn]

Winter rating is irrelevant at 35C. Use any 40-grade you want.

 

[legar]

I realized Amsoil doesn't have 5w-40 grade for their signature series. They have it in their European series (full-SAPS and mid-SAPS). I don't know if it's a good idea to use them in a Nissan. Torn between 10w-40 premium protection and 5w-40 euro.

 

[kschachn]

I realized Amsoil doesn't have 5w-40 grade for their signature series. They have it in their European series (full-SAPS and mid-SAPS). I don't know if it's a good idea to use them in a Nissan. Torn between 10w-40 signature and 5w-40 euro.

Why?

 

[legar]

Why?

That's what I'm asking actually I don't know if it's fine to use it or not. Curious which one is the better option for my use case.

 

[kschachn]

It’s fine. And you won’t ever detect a difference between those two oils.

 

[Razorsharpe]

I use Amsoil 0W40 Signature Series in my 2023 BRZ. You can use any 40 weight you want. 0, 5, 10. It won’t care.

 

[SR5]

The 2004 manual assumed mineral oils. Now days everyone is using full synthetic oil, which has a better winter rating and so a lower first (xW-) number. Nothing to worry about.

I would use a Euro rated (A3/B4 full SAPS or C3 mid SAPS) full synthetic as either 0/5W30 or 0/5W40. Anything with C3 or A3/B4 is high HTHS (3.5 cP or above) and should offer good protection.

For example (A3/B4) M1 0W40 or Castrol Edge 5W40.
For example (C3) M1 ESP 5W30 or Pennzoil Platinum Euro L 5W40.

 

[userfriendly]

My three Duramax owners manuals, 2006 LBZ, 2011 LML and 2018 L5P all state that 5W40 and 15W40 are recommended, but don’t use 10W40.
I have two 20L pails of 10W40 Duron CK-4/SN and don’t know what to do.
Should I dump it in the recycle tank?

 

[legar]

For example (A3/B4) M1 0W40 or Castrol Edge 5W40.
For example (C3) M1 ESP 5W30 or Pennzoil Platinum Euro L 5W40.

I tried to do some research but it kinda went over my head. How do I decide between full vs mid saps? Why/how does it matter in my case?

 

[goingplacesanddoingstuff]

You can use any winter rating in the summer, it doesn’t matter. 0W is only significantly better once temps hit about -10F to -20F. For temps over about -20F, 5W is fine. For temps over about 0-10F, 10W is OK.

If you live somewhere it doesn’t get that cold, which if you’re daily driving a 350Z I presume you do, I’d go with the Amsoil SS 10W-40. The advantage to the heavier winter ratings is a lower viscosity index and less VII, which translates into an oil which holds grade longer and may have somewhat better high temp properties.

 

[ChristianReske]

In the year 2000, Honda wrote in the owners manual of the S2000 that only 10W-30 is allowed.
BUT you can use 5w-40 in winter, below freezing point. Honda never changed this reccomendation until production ended in 2010.
This really weird reccomendation puzzles S2000 owners since.
In Germany and Europe, S2000 owners use 5w-40 and the engines run fine and long.

 

[SR5]

I tried to do some research but it kinda went over my head. How do I decide between full vs mid saps? Why/how does it matter in my case?

For your car (2004) I would use full-SAPS which is A3/B4.

The SAPS level is about preserving the exhaust cats. The modern way is lower SAPS, but back in 2004 it was higher SAPS due to lower quality (sulphur content) fuel.

If it was me I would buy a 40 grade (0W40 or 5W40) that is both A3/B4 and Porsche A40. These are easy to find, Castrol Edge, M1, Pennzoil Platinum Euro, etc

 

[GR_CoB]

For your car (2004) I would use full-SAPS which is A3/B4.

The SAPS level is about preserving the exhaust cats. The modern way is lower SAPS, but back in 2004 it was higher SAPS due to lower quality (sulphur content) fuel.

If it was me I would buy a 40 grade (0W40 or 5W40) that is both A3/B4 and Porsche A40. These are easy to find, Castrol Edge, M1, Pennzoil Platinum Euro, etc

I will add a little info on why the Porsche A40 approval is important.

Here is Porsche A40 testing procedure:
This test will last 203 hours. The engine, and the oil, will go through:
- 4 times the simulation of 35 hours of summer driving,
- 4 times the simulation of 13.5 hours of winter driving,
- 40 cold starts,
- 5 times the simulation of 1-hour sessions on the “Nürburgring” racetrack, A full lap of the Nordschleife, bypassing the modern GP track, is 20.832 km (12.944 mi) long. A stock Chevrolet Corvette C5 has a lap record at Nurburgring @8:40, stock Honda S2000 has a record@8:39, and stock Honda NSX is @8:38. Considering these numbers, this Porsche A40 simulation is equal to 80-90 miles of flatout track use. Or 100-120 miles if you drive Porsche 911 GT2 R with its lap record @6:38.
- 3.5 hours of “running-in” program
Measurements on the engine and on the oil will be done at regular intervals, and the following parameter
will be taken into account to grant the approval or not:
- torque curve (internal friction),
- oxidation of the oil,
- Piston cleanliness and ring sticking,
- Valve train wear protection. Cam & tappet wear must be less than 10 μm.
- Engine cleanliness and sludge: after 203 hours, no deposits must be visible.
- Bearing wear protection: visual rating according to Porsche in-house method.
One more thing for comparison. Just a rough idea of how the numbers stack up. Take everything with a grain of salt.
Most daily driven cars have an average speed (over the course of an OCI) of about ~35mph. That would make the 203hr test an equivalent to 7,105 miles of driving.
Assuming the average speeds are higher, let's say 50mph, and the 203hrs are now equivalent to 10,150 miles of driving.

 

[SR5]

My three Duramax owners manuals, 2006 LBZ, 2011 LML and 2018 L5P all state that 5W40 and 15W40 are recommended, but don’t use 10W40.
I have two 20L pails of 10W40 Duron CK-4/SN and don’t know what to do.
Should I dump it in the recycle tank?

You know what to do.

They were saying to use 5W40 synthetic or 15W40 mineral, but do not use old school 10W40 mineral.

You have a modern CK-4 10W40, that would be at minimum a semi-synthetic and probably a full synthetic. It will be just fine.

Which did you get the mid-SAPS E8 & E11 or the older spec and probably a bit higher SAPS E7 & E9 ?

Anyway, if you're worried, send them to me, I'll dispose of them in 5L increments via my Nissan.

 

[Fahrvergnügen]

When I was a tech at Nissan, lots of enthusiasts requested mobil 1 0w40. We put it. We stocked it anyway for GTR.

 

[userfriendly]

You know what to do.

They were saying to use 5W40 synthetic or 15W40 mineral, but do not use old school 10W40 mineral.

You have a modern CK-4 10W40, that would be at minimum a semi-synthetic and probably a full synthetic. It will be just fine.

Which did you get the mid-SAPS E8 & E11 or the older spec and probably a bit higher SAPS E7 & E9 ?

Anyway, if you're worried, send them to me, I'll dispose of them in 5L increments via my Nissan.

Far too good for your Nissan.
I have the original CK-4 variant offered in North America: 100C 15.5, hths 4.4 with a flash point of 240C and a base number of 10.
The Euro E8 has a bn of around 13.
Before I Bullydog’d, Banks’d and deleted my LML, I tried old school pcmo 10w40. In 13,000 kms it went from 15.5@100C to 11.8.
Duron sae 30 held at 11.8 at drain time and Duron 40 14.6.
A Petro-Canada employee told me that their conventional pcmo’s were crap, but I had to find out for myself.
I trust the current api sp offerings are better.
Mostly short tripped, gtx sp 10w40 is in my daughter’s 2022 3.6L Acadia.
Going into 2024, I was sitting on 400 litres of engine oil. I’ll get to the 10w40 Duron eventually.

 

[legar]

Thanks for all the help! This is what I decided to go with: AMSOIL 5W-40 FS 100% Synthetic European Motor Oil

Application specs: API S. SM...ACEA A3/B3, A3/B4; BMW LL-01MB-Approval 229.5;Porsche A40; WW 502.00, 505.00;GMLL-B-025; Renault 0700, 0710

 

[Brian123]

Thanks for all the help! This is what I decided to go with: Amsoil European Motor Oil SAE 5W-40 FS

Application specs: API S. SM...ACEA A3/B3, A3/B4; BMW LL-01MB-Approval 229.5;Porsche A40; WW 502.00, 505.00;GMLL-B-025; Renault 0700, 0710

Nice Choice, if you are not Burning Oil a FS Oil will be fine.