5W-30 or 10W-30

[Imowmylawn]

Rocketman,
Doesn't just the fact that oil leakage is "expected" with synthetics discourage usage in an air-cooled 4-cycle engine???

IMowmylawn,
Most engine manuals have a chart like below which shows single/multi viscosity recommendations(this also has excerpt from Gravely Support at top):

My manual for the actual mower shows the first pic while the engine manual shows the second one. Both say 10W-30 for this temp and the engine manual says synthetic is ok.

 

[djdicetn]

My manual for the actual mower shows the first pic while the engine manual shows the second one. Both say 10W-30 for this temp and the engine manual says synthetic is ok.

Imowmylawn,
Well, it seems that Kohler differs slightly from Kawasaki (and I think Briggs & Stratton) in mentioning/recommending synthetic. Since you have a Kohler(I lean towards what the engine manual says over what the mower manual says) you are well justified in seeking and considering using synthetic oil. Thanks for enlightening those of us not familiar with Kohlers!!

 

[exotion]

Imowmylawn,
Well, it seems that Kohler differs slightly from Kawasaki (and I think Briggs & Stratton) in mentioning/recommending synthetic. Since you have a Kohler(I lean towards what the engine manual says over what the mower manual says) you are well justified in seeking and considering using synthetic oil. Thanks for enlightening those of us not familiar with Kohlers!!

I started reading this thread I have always used 10w40 oil in my mowers never had a problem its nice and thick for long period uses in hot temps :/ plain ol what ever is cheapest oil :/

 

[djdicetn]

I started reading this thread I have always used 10w40 oil in my mowers never had a problem its nice and thick for long period uses in hot temps :/ plain ol what ever is cheapest oil :/

All of this discussion about what's best for an air-cooled mower engine prompted me to call my dealer and talk to the service tech(since I'm doing the first oil change on my Gravely this weekend). I asked him if using the Briggs & Stratton SAE engine oil from now on versus a multi-viscosity or synthetic was recommended from his mechanic's point-of-view. He told me he agreed that for our climate, unless I mowed in weather below 32 degrees(which I definitely don't), that usage of SAE 30W designed for small engines and 50 hour oil changes would (A)not void my warranty and (B)my engine would last many, many problem-free years. I'm gonna just take my chances with what has worked for me for 20+ years(B & S oil).

 

[ebk]

I just wanted to add my two cents worth on the viscosity issue. I happen to agree with the previous post from djdicetn. I use a straight weight SAE 30W synthetic oil in my mower. I have noticed in my Yukon that if I go beyond oil change recommendations, with heat and contamination, the oil viscosity improvers in multi-weight oils will lose their ability to thicken the oil at operating temperature. My last oil change was overdue and my synthetic 5W-30, at operating temperature, came out like a 5W. Keep in mind that this is in a water cooled engine that operates much cooler than an air cooled engine. After your warranty, you may want to look at a straight weight or dig more into oil. Good article: Motor oil Breakdown and an exhaustive, everything you want to know about oil, reference: http://hyperformancecycles.net/oil_bible.pdf Straight-weight synthetic oils are hard to find. I use Royal Purple synthetic SAE 30W to minimize damage to my engine. I am sure there are others out there. However, many synthetics are group III synthetics, which are typically made from mineral based oil stocks . Not pushing RP, but theirs is a group IV synthetic, formulated from non-mineral synthetic esters, vs the mineral based group III oils. BTW, in some countries group III oils are not allowed to be marketed as synthetic oil.

Probably TMI, however I thought it might help.

 

[dougwin]

I use Mobil 1 full synthetic 0 W 30 in all my lawn equipment, which includes: Honda HHT25S string trimmer (over 600 operating hours), Toro Super Recycler mower (over 200 operating hours), Husqvarna HU800AWD (over 40 operating hours). Even the 0 W 30 is much thicker at room temperature than 30 weight oil at engine operating temperature (200 degrees or more). The synthetic oil holds up exceptionally well at high temperatures such as in air-cooled engines and turbochargers. For a very readable discussion on oil viscosity I like - Bob is the Oil Guy, who works a lot with air-cooled motorcycle engines.

 

[carlcap1491]

Let me start by saying sorry if is in the wrong place...
I have a Husqvarna LGT2554 with a 25HP Kholer Engine...I recently bought some Quaker Stake Ultimate Durability full synthetic 5W-30 for my car...I bought 10 quarts (sale) and my car takes 6...i was wondering if i could use that to change the oil in my lawn mower...the manual calls for 10W-30 above 32F...but in about 70-80F would the 5W be ok? if i idle for a bit first before increasing throttle maybe? I dont want to have to go buy more and i really want to use synthetic. Thanks for your help! Also, is QSUD a good oil to use since it's for a car engine and not a small engine?

I would say definitely you can use the full synthetic 5W-30 motor oil for you lawnmower but, you should check the oil level every time before you use your machine. I have used 5W-30 regular oil in my lawnmower and never had a problem but, I always check the oil level before every use.

 

[oldyellr]

The difference between 10W30 and 5W30 is that at freezing temperatures 10W congeals more than 5W. That's for cold starting in winter. Both oils are 30 viscosity at operating temperature. In fact, because of its wider viscosity range and steeper viscosity curve, 5W30 likely does not thin out as much as 10W30 when ABOVE normal operating temperature. Add to that, being synthetic is an extra margin of safety. I would not hesitate to use 5W30. It's just a lawnmower, not a race car.

Better yet, why not save the synthetic 5W30 for the next time your car needs an oil change and just get some cheap Walmart 10W30 for the mower?

 

[exotion]

The difference between 10W30 and 5W30 is that at freezing temperatures 10W congeals more than 5W. That's for cold starting in winter. Both oils are 30 viscosity at operating temperature. In fact, because of its wider viscosity range and steeper viscosity curve, 5W30 likely does not thin out as much as 10W30 when ABOVE normal operating temperature. Add to that, being synthetic is an extra margin of safety. I would not hesitate to use 5W30. It's just a lawnmower, not a race car.

Better yet, why not save the synthetic 5W30 for the next time your car needs an oil change and just get some cheap Walmart 10W30 for the mower?

I still stand by my 10w40 we have a wide range of temps in spokane we start out close to freezing and end our day with 80 my mowers get frequent oil changes and never had an oil issue. My honda takes 13. Ounces that's nothing compared to my toro at 23 my local napa has a sale on castrol gtx 2 dollars a quart I bought 20.

 

[motoman]

lmow, You have touched the favorite topic on this forum. I like 5w-30 and use it in my Intek 24 year round. Your engine will probably kick out more out which is good in my opinion . I add about 2-3 oz top up-to keep the sump full after each 1-1/2 hrs of mowing. Oil pressure is 35-40 psi even in 85F. If you are in warranty it probably is a good idea to document your purchase and stay with the manual call out. The 10w part of the oil is maintained by additive pak which is depleted fairly soon and leaves you with 30w. Better cooling is achieved by flow which a lighter oil provides. I also use my Nissan auto oil, Chevron.


edit: I was rereading this thread. The wife's German car (7500 red line) uses 0W-40 per mfgr. The stuff goes in like water. So much for thin oil not holding up, Our tractors run at "fast idle" 3000 rpm.