Some confusions associated with 30 and 40 wt.

[sgvaibhav]

Hi,

I have some confusions associated with 30 and 40 wt oils when viewed from different factors.

Firstly I use 10W40 in my 2008 Nissan Versa/Tiida - 1.6L engine.
I live in UAE - so its summer/desert.
Outside temperatures are high.
Assume a peak of 50 deg C. (That is hot, but comparing with other countries having temperatures of 30 deg C, its only about 20 deg C hotter, which might not seem much when compared to the temperatures found under the hood).
The engine is NOT oil cooled.

My manual recommends using SAE-5W30 with API SL or API SM
However another picture is shown in the manual, which shows the possible SAE ratings that can be used which I am attaching.
Recommended Oil Viscosities

Now here are my concerns-


I have never used a SAE xW-30 oil, since it is quite rare here.
Only 40wt and 50wt oils have been used in my car.
I have found 40wt oils much better, they *sound* better (quieter), and feel *smoother* whilst accelerating.
I am a guy who likes going close to redline, 5K rpm to 6K rpm are seen once or twice in my daily trip.


So firstly I wanted to know if using 30wt oil is any risky (oil pressure loss?) because of the climate, and will it adapt to my accelerating habits.
(I think it should not because my engine is not oil cooled, however you guys can tell me better about this).

I am eager to move 30wt oil because i expect more better sound *quietness* and more better feel *smoothness* than a 40wt oil, and some fuel savings IF ANY.


Can a 30wt oil do this safely?

If yes, I shall move to my next concern.

 

[rikstaker]

I used to live in Saudi arabia and I owned a Civic, I used both Mobil 1 0w-40 and Fuchs 5w-30, With stop and go driving with ac running.. in scorching heat, the engine can get really really really hot... Stick with the 40 weight.

 

[Lead Shoes]

30wt will be able to protect your engine properly at those temps, people run 5w20 as per the MFG specs in Arizona which is just as warm with no ill effects... stick to what the MFG wants, which is a (X)w30 as stated in the picture.

The ideal choice would be a stout 10w30 diesel oil for your circumstance imo.

You seem to not trust a "light oil" if that's the case stick with the 40wt oils

 

[Oregoonian]

Its my understanding the 'lighter oils' run COOLER. If that is true, than a 5w30 would be appropiate for your driving habits.

Your engine should run slightly cooler in those hot temps, and you might possibly see a slight increase in MPG.

 

[aquariuscsm]

Did you say out of a 40 and 50,the 40 ran better? I'd stick with the thicker oils,a good 40 weight. Thicker seems ideal to your environment. Hot ambient temp,and hard driving.

 

[supercity]

I know UAE traffic drives FAST! And in that climate it really isn't going to matter what you use. I would happily use a 40 over a 30 if it were the same price or cheaper.

 

[Cristobal]

I think in that climate, you can use the heavy oils just fine. Personally, I would use a 10W-40 and call it a day. The engine should do OK with the lighter oils, but since it is not cold anyway when you start the engine, why not just take advantage of the heavy oils, as they are often slightly less expensive?

I am not an engineer, but I think that in really hot weather the heavier oils can take a beating better.

 

[y_p_w]

Even in a place where 5W-30 is the most common, I've seen recommendations for 10W-40 in certain ambient temperature ranges. My 2004 Subaru's owner's manual says that for desert temperatures or towing that weights such as 20W-50, 20W-40, 30, or 40 can be used.

Honestly - most engines will tolerate a huge range of motor oil weights. The primary recommendation for 5W-30, 5W-20, or 0W-20 is to achieve better fuel economy. Most people do it because that's generally though of as the "warranty requirement". In a place as hot as the Middle East, I wouldn't have a problem using a quality 10W-40, especially with modern base oils and additives. Maybe there was a time when they tended to break down quickly.

However, if you're going that route, a decent 15W-40 diesel rated oil with a gasoline rating might be a good option.

 

[GSCJR]

You're engine IS oil cooled. Engine oil plays a large role in regards to engine cooling, about 70% IIRC.

 

[CATERHAM]

There is no need to run anything heavier than the specified 5W-30.
From the sounds of things your Nissan is not running higher than normal coolant temp's so you don't need to concerned at all.

 

[Clevy]

Originally Posted By: GSCJR
You're engine IS oil cooled. Engine oil plays a large role in regards to engine cooling, about 70% IIRC.


That's right. Oil cools more of an engine than coolant does.

 

[wally6934]

The manual you posted clearly says the preferred oil is 5W30, even up to the maximum outside temperature. It also says IF this oil is not available use another oil in the chart.

You said 5W30 oil is hard to find, then try one step down to 10W40.