Going from 0W40 to 5W30

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I'm planning to do an oil change on the I35 before winter sets in. It currently has Mobil 1 0W40, which really makes this engine purr like a kitten. I have some Valvoline MaxLife Synthetic 5W30 laying around I'd like to use up. This may sound like a noobish question but is there an issue switching from a 40 wt oil back to 5W30? Will it make the engine noisier, uncover leaks, etc?
 
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no, for engine break-in after a rebuild, I use whatever cheapest dino on hand (generally 10w30/10w40) because we dump it early at 5k. From then on we use 5w20/0w20, I have never seen an issue develop because of switching grades.
 
That Mobil 1 0W40 is a Euro ACEA A3/B4 and BMW LL-01 oil.

Is the Valvoline 5W30 the same? Or is it a SN / ILSAC GF-5 oil?

If the 5W30 is A3/B4 it should be similar to the Mobil 1 0W40 and is a long life oil. A ILSAC 5W30 is a different oil, more energy conserving than long drain interval.

So what does the OM say is the required oil spec? And how long a OCI are you going for?

I've never had a problem going up or down an oil weight grade with my cars, but I always use a oil that meets the required manufacturer specs.
 
Your engine calls for API SL 5w30 conventional, which easily shears to xW-20. Any modern (SN) oil of any type, brand, and viscosity well exceeds those specs. You will be using some better oil than your engine was made for regardless. So, rest assured whatever you decide to put in even though probably none will exceed the performance of Mobil 1 0W-40 SN.
 
Originally Posted By: Merkava_4
Leave well enough alone is what I say. Your Infinity might not like 5w30. Might make it noisy.


I agree. Stay with the 40wt year round.
 
I'm going the other way in my car. From Mobil 1 5w30 to Mobil 1 0w-40. In reality, it's like going from a 30 wt to a 35 wt.

Using your leftover 5w30 during this winter makes sense. That will allow you to stay with the heavier 0w-40 in summer where it can do the most good.
 
Why not keep things simple and run 5w30 in the winter and 0W-40 in the summer?

Unless temps get really cold, your 14 year old engine will likely never know the difference.
 
Originally Posted By: 147_Grain
Why not keep things simple and run 5w30 in the winter and 0W-40 in the summer?

Unless temps get really cold, your 14 year old engine will likely never know the difference.


0w40 will out perform 5w30 in the winter too. It is 0w and not 5w so Id just use 0w40 year round.
 
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