Why not multigrade in lawnmower?

[Ook]

I bought a lawn mower and a tiller. Both came with jugs of 30w oil. Question. Why not use a good multigrade in them instead of the 30w?

[Rich256]

I suggest 5W30 Mobil 1. It has all the characteristics of a straight weight 30 conventional except it doesn't get as thick when cold, can stand a lot higher temperatures and has little or no viscosity improvers. The worst part of conventional multi grade is that it contains lots of Viscosity Improvers. It can be bad news for a hot running engine.

Amzoil ad but says the same thing:

See the section titled:

WHAT ABOUT ENGINES THAT ?REQUIRE? A STRAIGHT WEIGHT OIL?

[Pete C.]

Second the M1 5W30, I use it in pretty much everything but the two cycle stuff and it seem to work very well.

Pete C.

[Eric in North TX]

I run Rotella 5w 40 synthetic in everything. It a diesel rated synthetic that tests out better than Mobil 1 at a better price. I have a lot of engines and needed something that would work in all of them. I use it in everything form the 4 stroke weed wacker to the backhoe.

[Steve Barker LT]

I don't think you can use the word "good" and "multi-grade oil" in the same sentence. I use straight 30 in everything I own. Always have, always will.

[lwasserm]

Uhhh, because you already have the 30w they came with?

[Nate Nagel]

They are probably air cooled so the single weight may provide more protection at high temp. just a guess...

nate

[Joseph Meehan]

Because that is a remnant of the pre-synthetic days. Standard multi-grade oils don't perform well in an air cooled small motor. They tend to break down and end up as 10W and worse. Synthetic oils however can handle the heat and should be fine.

Thanks for the question, because it is time for an oil change on my mower and I believe I am out of 30W but I have good synthetic around. I will switch. I just had not thought of it.

[m Ransley]

You got 30w with them because its cheaper for the manufacturer. A multi grade synthetic is better.

[Bennett Price]

Because single weight is cheaper and the manufacturer doesn't think synthetics or multiweights are necessary. If you use them, they won't hurt anything but your pocketbook.

You're not going to run either machine in sub-freezing temps or go for

150,000 miles.

You might check out the website of the eng> I bought a lawn mower and a tiller. Both came with jugs of 30w oil.

[GWB]

John Deere recommended Turf-Gard (their brand) in 10w-30. I figure they oughtta know, so that's what I use.

[trader4]

I wouldn't second guess the advice of the maufacturer. And unless there is evidence, I wouldn't assume or jump to the conclusion that price of the oil has anything to do with it.

For example, for my boat, Mercruiser lists straight 40W for their V8 marine engines, with no off the shelf multi-grade recommended. Now it's hard for me to believe they are doing that based on oil cost, since in marine applications, the cost of oil is trivial.

And it's not true that mulit-grade is not used in lawn mowers. My Honda takes 10-30.

I would use the recommended oil and make sure it's changed at least the recommended hours or once a season.

[Rich256]

You might consider synthetics as being a single grade oil. And synthetics are much better at standing the high temperatures you find in air cooled engines. It just happens that it does not get as thick as conventional oils when it gets cold and will meet the 5W30 specification without additives. In order to get conventional 30 weight oil to thin out when cold it is necessary to add viscosity improvers. The VI has been a disaster in some of the hot running car engines. Note that some now will not warranty an engine if you use 10W40 conventional oil. I saw one engine where the rings were froze into the pistons due to the VI. It was necessary to throw the pistons away.

The first number "5" means at 32F the oil has the same viscosity as straight weight 5 at 32F. The 30 means that at 212F it has the same viscosity as straight weight 30 at 212F. So when cold it is still thicker than it is when it gets hot.

[George E. Cawthon]

Single grade used to be cheaper, most places you can even find it. You don't need anything better. than a good multigrade. I think using single grade is a big myth just using non detergent oil.

My lawnmower motors last till everything else falls apart. I have used multigrade for a long time (at least 10W-30 and 10W-40 is probably better. Change the oil at least once a season, two times is better, and at least every 25 hours. Clean the air filter at least every season and adjust the carb correctly as needed, about 1/2 way between rpm fall off at two rich and two lean; too lean burns valves so stay toward rich side.

Biggest point is having the engine full of oil and keeping the oil clean.

[Al Bundy]

GWB wrote in news:heopk2llvpthpld1dt5rd7cr6tfe83pvj9@

4ax.com:

...and Zippo says only use Zippo fuel in their lighters. I wonder what they pay for a barrel of generic Naptha?

[Ook]

Do the air cooled engines get that much hotter? I'm using penzoil 10-30, but it's been pretty cool this summer, and I've not mowed in temps above 70.

[Rich256]

Yes, and it is cheap insurance to put in a good synthetic. They seem to stay cleaner a lot longer too.

[GWB]

It's a $5000 tractor; I think I can afford a couple of quarts of overpriced oil a year.

[Joseph Meehan]

The problem is uneven heat. Some spots are much hotter than they would be in a water cooled engine since water carries away far more heat per volume area than air.

[spud2004]

Good Post but you have it backwards They start with the low no. base oil

5W then add Polymers which prevent the oil from thinning as much as it warms up 10W-40 and 5W-30 require a lot of polymers polymers can shear and burn forming deposits and frozen rings as you say among other things The wide range oils are more prone to viscosity and thermal breakdown due to the high polymer content And leave you with the base oil You wouldn't put single grade 5w in would you So when it breaks down you have 5W base not 30W 10W-40 IS Well know to do this and As you said Very few manufacturers recommend 10W-40 any more and some threaten to void warranties if it is used So the other post that said 10W-40 is probably better is flat wrong 20W-50 is the same 30 point spread But has less polymers

Spud