# 5w-30 vs 5w-50 synthetic



## gcclubs (Jan 9, 2011)

My snowblower recommends 5w-30 synthetic as one choice but I have some unopened containers of mobil 5w-50 synthetic and would like to use it vs wasting money on new oil. My understanding is that a start up both oil have the same effective weight and at operating temp one has 30 weith and the other 50. Any thoughts on using what I have?


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## pfn (Dec 24, 2010)

I doubt you would see any problems early on or maybe even down the road but I think they recommend 5w30 for a reason. You are talking about less than a $10 expense. I wouldn't chance it. FWIW.


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## BOSMECH (Dec 16, 2010)

There should be no problem at all the good thing is it is synthetic.


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## CharlesW (Oct 13, 2010)

The manufacturer recommends 5W-30 and that's what I would use.

Oils with a wider viscosity range have more "viscosity modifiers" in order to achieve that wider range.
These viscosity modifiers tend to shear (break down) during use - sometimes rather quickly. Some of these modifiers can build up on the sides of the pistons, rings, and on other hot parts inside the engine to the point of reducing oil flow to parts of the engine - not a good thing. 

FWIW, Much of the comment about viscosity modifiers was plagiarized.


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## dakota60 (Oct 20, 2010)

Keeping in mind that this is most likely a splash lubrication system, I would worry about using oil of such a high viscosity, synthetic or not .Larry


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## Ingersoll444 (Nov 20, 2010)

Ive never used 5w50, but have used 5w40 synth for years. I beat the tar out of my cheapy MTD and the thing gets almost no maintance... still runs fine.. I just have access to the 5w40 so thats what I use.


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## HDNewf (Nov 23, 2010)

gcclubs said:


> My snowblower recommends 5w-30 synthetic *as one choice* but I have some unopened containers of mobil 5w-50 synthetic and would like to use it vs wasting money on new oil. My understanding is that a start up both oil have the same effective weight and at operating temp one has 30 weith and the other 50. Any thoughts on using what I have?


You can use it with no problems because:

1. It's a snow blower, you will be changing this oil each spring (I hope) and so it won't even get very dirty before it's gone.

2. What Charles W said is true, but because this oil is synthetic, the amount of viscosity modifiers is fairly low, and due to 1. above it won't be there for very many hours.

3. Since synthetic oil is only one many choices, it must be ok to use regular oil, which offers less protection than synthetic.

4. It is 5W-xx and as such is just fine for the cold starting lubrication needed by a snow blower. In addition, the 50 rating just means that as it gets hot, the oil thins out less than a 30 rated oil. It is not the same as a straight 50 weight oil.

I hope this helps,
HDNewf


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## road_rascal (Dec 13, 2010)

I've been using 5w/40 Rotella full syn in my snowblower, lawnmower and motorcycles for years and never had a problem.


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