5w30 Synthetic vs 20w50 Mineral oil

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Oct 31, 2022
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Hi,
I recently purchased a second hand 2011 Suzuki Grand Vitara 2.4L Inline 4 Cylinder SUV which has clocked over 195k Kms on the odo. I live in the United Arab Emirates where the summer temperature reaches 50 Degree Celsius. The oil which was being used in it was 20w50 Mineral changed at every 5k Kms.
I want to switch it to Synthetic oil at 10k Kms OCI.
Now, my main question is, here the amsoil and castrol dealer recommend to switch to 5w30 Synthetic oil, my concern is that with respect to its age and life, the 20w50 might have caused clearances in the inside components of the engine, and using a 5w30 now would not give me protection as it is thinner. what is the clarification on this?
I dont want to change to 5w30 and then hear unnecessary sounds from the engine or oil pump and then again switch back to 20w50 as it would be a waste of money.

Any recommendations on what should be done?
 
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.
Why is 5W-30 a substitute for 20W-50 and vice versa?
That said I don't understand using mineral oil. So, yes
I support the vote for synthetic and 10,000 km OCIs.
If you don't feel comfortable with 5W-30 why don't get
some synthetic 5W-40? What does your manual say?
.
 
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- 20W50 did not affect the clearances inside your engine. If anything - it may have prevented some wear by providing extra oil cushion between parts. That "cushion" is known as MOFT - Minimum Oil Film Thickness.
- 5W30 in your climate may cause a little extra wear and you may hear the valvetrain more when the engine is really warmed up after a long highway ride, or long spirited drive, etc. On the other hand - being synthetic and lower viscosity will help keep temps down in the bearings on normal days with normal load.
- In your climate I would use a synthetic 5W-40, as @930.engineering suggested above. Using a synthetic 5W-40 that is "Porsche A40" and "MB 229.5" certified will be even more beneficial, as those are very stringent certifications and oils meeting those certs will be truly stout oils.
- If you plan to use Amsoil - 5W-40 Signature Series is the one to use.
Edit: looks like Signature Series is available in 0w-40 and 5w-50 grades. Seems that 5W-40 got its own Amsoil European lineup.
 
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So many ways to begin a THIN vs thick thread. 🧐

I wouldn’t change anything.
Complete with concerns about “clearances” and “protection”. At least it wasn’t tolerances.

In that climate a 50-grade oil with a 20W winter rating is just fine.
 
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I would definitely use synthetic. And, when you buy oil, you buy whatever grade you want. You are not forced to buy 5w30. Find a 40 or 50 grade synthetic oil, 5w40, 10w40, 10w50, 15w50, or 20w50... and keep driving. Shops/mechanics don't tell me what to buy and I don't care about their recommendations. I tell them what I want and that's it. You might not find every grade with every brand. So, shop other brands too.

I haven't seen automotive synthetic Castrol 50 grades in stock anywhere. I can usually order the 10w60, 10w40, and their 5w40's. Their website shows Castrol syntec 5w-50. So, you'll have to check to see what is available in your local store.

Amsoil does have Premium Protection 20w50 and Signature 5w50. These two would be easy choices.

Since you want to increase your oil change interval from 5k to 10k km, I would make sure that you check the oil level often and top it off frequently.
 
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I would probably use a diesel oil. 15w-40 is probably better than the mineral 20w-50 its been getting.
 
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In your climate and driving conditions keep using what carried your engine to 195k miles. Dealers want to sell you oil so there is a conflict of interest here.
 
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I'd ditch the 20W-50 molasses and run the 5W-30. All you're doing with the 20W-50 is increasing bearing heat with likely little or no benefit.
 
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In the USA, the same vehicle would spec 5w-30.

For the additional heat in the UAE, I would run a 5w-40 Euro. I'm not a big supporter of running diesel oil in gasoline engines.
 

tabrez.tb48de

Thread starter
Joined
Oct 31, 2022
Messages
9
.
Why is 5W-30 a substitute for 20W-50 and vice versa?
That said I don't understand using mineral oil. So, yes
I support the vote for synthetic and 10,000 km OCIs.
If you don't feel comfortable with 5W-30 why don't get
some synthetic 5W-40? What does your manual say?
.
The manual recommends 5w30, attached photo from the manual.
5w40 seems fully synthetic seems a good option, but the Castrol Edge which has that grade is currently rarely available, Castrol promotes their Magnatec 10w40 which is Semi-Synthetic (i guess)
unnamed (17).jpg
 

tabrez.tb48de

Thread starter
Joined
Oct 31, 2022
Messages
9
- 20W50 did not affect the clearances inside your engine. If anything - it may have prevented some wear by providing extra oil cushion between parts. That "cushion" is known as MOFT - Minimum Oil Film Thickness.
- 5W30 in your climate may cause a little extra wear and you may hear the valvetrain more when the engine is really warmed up after a long highway ride, or long spirited drive, etc. On the other hand - being synthetic and lower viscosity will help keep temps down in the bearings on normal days with normal load.
- In your climate I would use a synthetic 5W-40, as @930.engineering suggested above. Using a synthetic 5W-40 that is "Porsche A40" and "MB 229.5" certified will be even more beneficial, as those are very stringent certifications and oils meeting those certs will be truly stout oils.
- If you plan to use Amsoil - 5W-40 Signature Series is the one to use.
Edit: looks like Signature Series is available in 0w-40 and 5w-50 grades. Seems that 5W-40 got its own Amsoil European lineup.
Thats one of my main concern is hearing the unnecessary noises from the Valvetrain after using 5w30, will look into 5w40 or 10w40 options.
How about the Amsoil OE 20w50, Currently with the mineral 20w50, i am getting a mileage of about 7-7.5Kmpl (actual calculation, not the displayed) in city driving and this is pretty low for a 4 Cyl. engine.
Thats the main reason to switch to synthetic
 
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