10W-30 0r straight 30W? Why not 10W-40?

[JDgreen]

Has anyone noticed increased oil consumption in their push mowers while using 10W-30 rather than straight 30W? I am a stickler about using only 5W-30 in my auto engines but when it comes to small motors I really don't pay much attention to which one I use, between the two others. (10-30&30) The manuals caution not to use 10W-40 and I have never understood the reason why that weight would be any different from 10W-30, seems like it would better protect an engine in really hot weather.

 

[indypower]

It's not the weight. It's the API rating. 10W40 does not meet the requirements for small engines. And SAE 30 is on the way out as being recomended. 10W30 & 5W30 are the recomended oils now. The reason is the additives and how well they lubricate.

 

[JDgreen]

It's not the weight. It's the API rating. 10W40 does not meet the requirements for small engines. And SAE 30 is on the way out as being recomended. 10W30 & 5W30 are the recomended oils now. The reason is the additives and how well they lubricate.

The newest push mower I purchased last summer, with a Briggs 6.75, has an engine manual included that says below 40 degrees 30W may cause hard starting, but that weight may be used up to and over 104 degrees, and 10W-30 can be used in temperatures as low as zero, but use in temperatures about 80 degrees may cause increased oil consumption, with a ceiling illustrated of a naximum of about 98 degrees, and for 5W-30, the temperature range is very narrow, 40 DEGREES AND BELOW ONLY. (emphasis added) It does say any motor oil with an API rating of SF, SG,SH,SJ or higher may be used.

I have NEVER seen 5W-30 okayed for use in any air cooled small engine except for wintertime temperatures.

 

[twall]

Regarding multi-vis oil,

The first number (10w in 10w30) is how well the oil flows cold. (it will flow the same as cold 10w oil). The second number is the hot flow. You don't want to use 5w30 in a push mower, it'll just burn up, because it's so thin.

Straight 30w will be thick as honey when it's really cold (that's why it isn't reccommended for winter use), but thin right down at operating temp. The advantage, as you saw, is that it'll take a lot more heat.

10w40 is too thick at temp to lubricate properly and help with heat dispersion. Air-cooled engines are picky like that.

I always use 10w30 in the winter in all my stuff, (but my car) and straight 30w B&S oil in the summer. When the temp doesn't get below 60 at night, you don't see a lot of advantages to multi-vis.

Hope that answers your question.

 

[ILENGINE]

briggs is now recommending 5w30 full synthetic in their engines. Other manufacturers use 10w30 due to some mechanical requirements (hydraulic valve lifters in Kohler Command) which will overpump and cause valves not to close if 30w is used below 50 degrees. The main reason behind the use of lower viscosity oils today is due to flowability causes less friction to moment lowering emissions.

 

[twall]

briggs is now recommending 5w30 full synthetic in their engines. Other manufacturers use 10w30 due to some mechanical requirements (hydraulic valve lifters in Kohler Command) which will overpump and cause valves not to close if 30w is used below 50 degrees. The main reason behind the use of lower viscosity oils today is due to flowability causes less friction to moment lowering emissions.

True. But, if it's an older engine, the toerances aren't as tight, and 5w30 will tend to be way too thin. Also, A slinger system doesn't like wimpy oil, whereas a full-pressurized system can get the oil to the critical bits using thinner oil. Also, older B&S used solid lifters, and a thicker oil will keep them from clattering in the heat.

I guess it depends on the vintage of your push mower, JD.

 

[JDgreen]

briggs is now recommending 5w30 full synthetic in their engines. Other manufacturers use 10w30 due to some mechanical requirements (hydraulic valve lifters in Kohler Command) which will overpump and cause valves not to close if 30w is used below 50 degrees. The main reason behind the use of lower viscosity oils today is due to flowability causes less friction to moment lowering emissions.

The manual I got my info from does show 5W-30 synthetic in the chart, but nowhere in the written information (a quarter page) does it say a word about that oil.

 

[JDgreen]

True. But, if it's an older engine, the toerances aren't as tight, and 5w30 will tend to be way too thin. Also, A slinger system doesn't like wimpy oil, whereas a full-pressurized system can get the oil to the critical bits using thinner oil. Also, older B&S used solid lifters, and a thicker oil will keep them from clattering in the heat.

I guess it depends on the vintage of your push mower, JD.

My pushers, the oldest ones are 2004-05 vintage, recommended grade is straight 30W bit 10W30 is the alternate, that's why I was wondering about oil use because I pretty much use that multigrade.

 

[twall]

Like I use...

10w30 is the reccommendation for cold weather use, and Straight 30w is for the summer. I always use B&S 30w, because it has a lot of additives to keep 'er goin longer.....

 

[ILENGINE]

Briggs and Stratton has approved the use of 5w30 synthetic oil in all of there engines. Winter or Summer for all temperature ranges. The 5w30 synthetic wasn't approved by Briggs until a couple of years ago or so and is retroactive to older engines.