# Which weight oil to use? Synthetic? For discusion



## JLawrence08648 (Jan 15, 2017)

A re-occurring question is which oil to use.

Cars

As the years have gone by, manufacturers have recommended lower and lower viscosity oils, I remember when straight 30 ND (non detergent) was used, then came detergent oils and multi viscosity oils. 10w-40 being the most common I remember when you had to change oils between summer and winter. You used a 30wt or 40 or even a 50wt for the summer and a straight 10 or 20 for the winter. Then multi viscosity oils came about and what a relief, no more changing oils. In the past I've used 20w-50, 10w-30, & 10w-40. The best at that time was Quaker State Deluxe, though many used Quaker State Super Blend. Now? for the later cars, not from the 50s, 60s, 70s, and 80s, I generally follow the manufacturers recommendations being not sure if the reason to use the lower recommended viscosity oil such as 0-20wt is the result of needing a thinner oil to between the main bearings and races because of tighter tolerances, or a thinner oil to gain the benefit of increased mileage to meet CAFE requirements. Maybe a little of both? However, I now only use synthetic oil, ONLY! Since 1978.

I use synthetic oil because it doesn't break down as Dino oil does, it lubricates better, it seems to flow easier than Dino oil so it gets to the top of the engine faster especially in the cold weather, and compared to the irregularly shaped globules of Dino oil, synthetic globules, molecules, are round so lubrication is better by each molecule rolling over each other smoothly like running your hand over table of ball bearings. I've gotten better gas mileage when I switched to synthetic, and substantially better when I switched to synthetic differential oil, 75w-90 especially in the winter. You want to do a winter test, use Dino gear oil compared to synthetic gear oil, left outside.

Years ago I put 3 quarts oil of oil outside the garage door left in 0-5 degree temperature for several days, regular Dino multi viscosity oil, and 2 different weights of synthetic oil. The Dino oil poured out like honey in the summer, the synthetic poured like thick water, the difference in viscosity between the 2 synthetic was noticeable. For this reason, I don't think it really matters which viscosity synthetic oil you use, they all are the same, and pour the same.

By the way, if I remember correctly, viscosity is not a measurement of the thickness of the oil, it's a measurement of flowability which normally we normally equate to the thickness of the oil.

Since manufacturers recommend changing Dino oil at 7,500 miles, and some at 25,000 miles, using synthetic, I feel I can easily extend my oil changes to 10,000 miles, even 15,000. The old 3,000 mile changes was recommended in the 50s and 60s, tuneups and spark plug changes were at 12,000 miles! when oils were not rated or rated SA, SC, they were not as good as they are today! Today's oils are better, the engines are running cleaner, the oil is not getting as dirty nor sooner, engine tolerances are tighter so contaminants are not filtering down in to the oil, combustion is both more efficient and hotter so contaminants are getting burned off as engines are more efficient, gasoline is cleaner, why change the oil every 3,000 miles? Manufacturers have changed their recommendations. You have to get your head out of the 50s and 60s.

For lawn mowers and edgers, I use any crap, any! Whatever is the cheapest, $2 on sale? Fine, though my preference is a straight 30wt. It doesn't have to meet any of the newer requirements. If you have older "new" oil on the shelf from the 60s? 70s? 80s? I'll use it for a mower. It doesn't care. It's only a splash sump of every rotation of the piston/connecting rod/crank bearing to lubricate the cylinder walls. That's all the lubrication it does, lubricate the cylinder walls.

For lawn equipment used in the fall and winter, ground leaf blowers, I use a multi viscosity because it's easier to pull to get started and I get a faster start pull.

For 2 cycle engines, any, once I've used up my supply of Dino 2 cycle oil, I prefer to use synthetic 2 cycle oil, better lubrication, lower internal temperatures, less smoke. I run most of my 2 cycle equipment at 40:1 ratio, whether 32:1 or 50:1. On some equipment I do use the synthetic. For 2 cycle Toro snowblowers, I use outboard motor oil TC-W3 as recommended by Toro. The reason Toro states is their snowblowers run at a lower temperature than other 2 cycle snowblowers and need to use TC-W3. Hey, almost the same price, negligible, though in the past I have used Dino 2 cycle oils for it. They say over time there's going to be less of a build up of stuff on the cylinder walls, pistons, and reed valves.

For snowblowers, I use only synthetic oil for one reason, if you have a shed or keep your snowblower outside under a tarp, you need the easy flow of the synthetic for a faster start. For years I had a 12v car battery electric start Gravely convertible and used regular oil in that. I also had a 5hp Tecumseh Ariens, and that is so low horsepower (5hp-7hp), it pulled easily and started right away. If anything, a little shot of starting fluid got it running easily and quickly. When you move to the 8hp and above, 10hp, that extra bigger bore, the extra compression, if you leave your equipment outside, shed or covered, Synthetic will help with a faster start. There's no need to be concerned with oil being pumped to the top for quick lubrication of the engine as a car engine because it's only a splash sump. If you keep your snowblower inside an attached garage, heated or non heated, regular oil will be fine though I'd still use synthetic. It's only a quart and cheap enough and you don't even have to change it every year especially if you are in the infrequent snow States.

Several years ago I put bottled water in a unheated leaky wooden garage door storage garage formerly a barn, and it took days if not weeks if not at all! for the water to freeze, dependent on the temperature. I did the same for my non heated 2 door attached insulated sheet rock garage with garage doors that are metal and leaking, bi-level house. The bottled water put near the door eventually froze, eventually, in really cold weather. The bottled water left in the middle of the garage never froze.


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## orangputeh (Nov 24, 2016)

whatever the manufacturer suggests. they usually have tables for temperature and recommendations according to conditions etc.


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## russ01915 (Dec 18, 2013)

5w30 full synthetic all machines. No ifs, ands, or buts.


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## Miles (Sep 16, 2016)

Nice write-up on the history of oil, JLawrence! Thanks again for your technical expertise here.


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## JLawrence08648 (Jan 15, 2017)

russ01915 said:


> 5w30 full synthetic all machines. No ifs, ands, or buts.


Good choice using 5w30 and synthetic oil on all your machines. You don't need my endorsement but I endorse it! LOL

You got me thinking maybe I should be using synthetic oil in my lawnmowers but

The reason I don't use it for lawnmowers, lawnmower engines last a long time and I flip them often, sell them. I'm always finding another one to use to cut my grass and sell, or "better" than the one I'm using, or more to my liking, so I use that one and sell the other. And I always seem to find someone to give me their old new oil, moving giving it to me or I find it on the curb when walking the dogs, they may no longer be doing oil changes themselves, and in some cases unfortunately, the death of their husband and I'm acquiring shelf items.

Engines have low compression, hard starting due to low compression, burn oil, and blow smoke due to wear of the piston rings caused by friction of the pistons going up and down. If you can reduce that wear, your engine will last a longer time. Synthetic oil reduces friction, it's a much better oil in this regard, it's slippery. If you use synthetic oil, I believe your engine will last longer and it makes sense.


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## Mountain Man (Oct 14, 2018)

russ01915 said:


> 5w30 full synthetic all machines. No ifs, ands, or buts.


Yes. And even a lot of new summer equipment can use 5w30. So for simplicity sake, you can stock and use 1 oil for all equipment year round. Just watch the oil level, since increased consumption is possible for summer use.


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## russ01915 (Dec 18, 2013)

I buy 5 qts container of 5w30 full synthetic at WalMart for $17.47.


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## JLawrence08648 (Jan 15, 2017)

russ01915 said:


> 5w30 full synthetic all machines. No ifs, ands, or buts.





russ01915 said:


> I buy 5 qts container of 5w30 full synthetic at WalMart for $17.47.


So at Wal-Mart, buy their store brand, Super Tech, I've seen Pennzoil synthetic also for $17.50, this is little more than $3 a quart, Dino is $2 a quart on sale or in 5 quart containers, so for $1.10 a quart more than Dino, you can get a better quality oil where the engine may last longer at a minimal cost spaced over time. I have to rethink using Dino oil at all! (But what do I do with the stuff I have?)


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## Mountain Man (Oct 14, 2018)

JLawrence08648 said:


> So at Wal-Mart, buy their store brand, I've seen Pennzoil synthetic also for $17.50, this is little more than $3 a quart, Dino is $2 a quart on sale or in 5 quart containers, so for $1.10 a quart more than Dino, you can get a better quality oil where the engine may last longer at a minimal cost spaced over time. I have to rethink using Dino oil at all! (But what do I do with the stuff I have?)


I believe air cooled engines benefit greatly from synthetic oils. They run hotter than a car engine due to air cooling, dirt buildup, and summer heat. How many people actually change oil more than once a year, or every 2 years ! I run hour meters and change reguarly.


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## russ01915 (Dec 18, 2013)

JLawrence08648 said:


> So at Wal-Mart, buy their store brand, I've seen Pennzoil synthetic also for $17.50, this is little more than $3 a quart, Dino is $2 a quart on sale or in 5 quart containers, so for $1.10 a quart more than Dino, you can get a better quality oil where the engine may last longer at a minimal cost spaced over time. I have to rethink using Dino oil at all! (But what do I do with the stuff I have?)


I do buy the WalMart brand Super Tech 5w30 synthetic oil


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## UNDERTAKER (Dec 30, 2013)

* I run 10w30 syn or dino in everything I have.*


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## broo (Dec 23, 2017)

I had 2 quarts left for my snowblower, meaning I was good for two more years on this regular 5w30 dino oil.


However something happened and the bottles cracked open when falling on the floor from the mezzanine.


So this year will be the first one my SB sees synthetic oil in its life. I'm trying Supertech 5w30. According to opinions on Bobistheoilguy forum, it seems like a very good oil yet it's still cheap for a synthetic. Barely more expensive than dino.


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## obionekenobi (Sep 3, 2015)

I run full synthetic on my vehicles and power equipment. Only ran dino oil for break in of power equipment. 5w30 for the snowblower and 10w30 for the mower, trimmer, and pressure washer. I agree I think synthetic is great for air cooled engines as they typically run hot and don't have oil filters. I think that if you change the oil annually though it probably won't matter that much in the long run.


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## GeekOnTheHill (Oct 11, 2018)

Unless otherwise specified by the manufacturer, 5W-30 dino or blend during break-in, and 5W-30 full-synthetic thereafter.

I usually use Mobil Delvac1 5W-30 in small, air-cooled, gasoline engines. It's actually a diesel-rated oil that also has an SN rating for gasoline engines. I've found it well-suited for small engines in general.

Richard


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## russ01915 (Dec 18, 2013)

Super tech Wal Mart

The Super Tech motor oil meets or exceeds the latest North American new vehicle warranty requirements API SN, ILSAC GF-5 and previous API gasoline engine classifications SM, SN and ILSAC GF-4
Superior low-temperature and high-temperature protection over conventional oils
Anti-wear additive to help extend engine life by reducing wear and oil breakdown
Compatible with leading conventional and synthetic motor oils


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## dr bob (Dec 12, 2015)

I've been a synthetic believer for cars-trucks-OPE for a while. Watching how engine manufacturing has improved so much in the last couple decades, I've moved away from any dino-oil break-ins. I look at "break-in" as the first stage of "wear-out". Rings seat almost immediately these days, with just a few at-load revs. I still believe in draining that initial fill soon after first run, mostly to get any possible casting sand or wear debris out as soon as possible. For those who think that the car needs a better oil than their OPE, I think both deserve the better synthetic oils. My OPE, particularly the snowblower, sees a much higher percentage of max available load than the cars do. So for the higher load, no oil filter, no serious engine temperature control snowblower duty, the nod goes to the same Mobil-1 that lubes the Honda and the Toyota and the Porsche, although the older Porsche demands 15W-50. 

So far so good with this protocol.


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## GeekOnTheHill (Oct 11, 2018)

dr bob said:


> I've been a synthetic believer for cars-trucks-OPE for a while. Watching how engine manufacturing has improved so much in the last couple decades, I've moved away from any dino-oil break-ins. I look at "break-in" as the first stage of "wear-out". Rings seat almost immediately these days, with just a few at-load revs. I still believe in draining that initial fill soon after first run, mostly to get any possible casting sand or wear debris out as soon as possible. For those who think that the car needs a better oil than their OPE, I think both deserve the better synthetic oils. My OPE, particularly the snowblower, sees a much higher percentage of max available load than the cars do. So for the higher load, no oil filter, no serious engine temperature control snowblower duty, the nod goes to the same Mobil-1 that lubes the Honda and the Toyota and the Porsche, although the older Porsche demands 15W-50.
> 
> So far so good with this protocol.


The only advantage to using dino or a blend during break-in is that dino is better at keeping metal in suspension. In theory, break-in is the time when the oil is most likely to have metal in it, which is why many old farts like myself still shun synthetic during the first few hours. I agree that it's probably not necessary given the more precise engine manufacturing methods used today, but old habits die hard. 

I also agree that OPE engines (especially air-cooled engines) work a lot harder than most vehicle engines and need high-quality oil. I especially shake my head when people use the oil they drained from their cars in their OPE. I'm a tightwad from way back, and even I don't do that. Any used oil beyond what I need to silence squeaky door hinges goes to the county recycling facility.

Richard


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## DuffyJr (Oct 15, 2015)

For my blower I use any 5w30 I can get on sale. For the mower I've been using Rotella T5 (CK-4 rated) and before that Kohler (SJ,SH rated) both 10w30 which are HD oils which I think handle the heat and dust in the summer better. I know it's not necessary but it doesn't cost that much more and I hoping my current mower will be my last one plus I think what oil you use is more for what ever makes you sleep better.


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## E350 (Apr 21, 2015)

This Summer I started running Klotz Jet Craft at 32:1 in our 25-year old stand up 2-cycle jet skis. And use it in the 2-cycle landscape equipment and in the chain saws. 

Klotz Synthetic Lubricants


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## IDEngineer (Oct 16, 2018)

I have a relationship with the marine (boat engine) industry. Marine engines often sit unused for a while (think casual owners who only fire them up on weekends, and maybe not even every weekend). There was an extensive study of oils in such occasional use engines a while back, and the results showed that synthetic oils did, in fact, flow better - which was considered a DISadvantage in occasional use engines. Why? Because liquid dinosaurs left the upper portions of the engine better lubricated for longer, easing wear on those parts when the engine was cold started. The engines filled with synthetics were "dry" on their upper internal surfaces because the synthetics flowed better, and thus drained back down over a few days of sitting idle.


Obviously this didn't resolve the argument between the liquid dinosaur advocates and their equally passionate synthetic advocates, but it was a conclusion I hadn't seen before. As a result, I use synthetics in my daily engines and liquid dinosaurs in my occasional use engines (such as snowblowers, ATV's, all marine engines, etc.). Cars and trucks get driven frequently enough to keep a protective film on their upper surfaces, but occasional use engines might sit for a week or more before they get started again... and when they do get started, they're running dry until the oil pressure can build and then pump oil to all those dry surfaces.


Disclaimer: YMMV, just my $0.02, this opinion worth no more than you paid for it, etc.


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## paulm12 (May 22, 2015)

Interesting point of view on the occasional use machines. I'll have to look for that study. I understand the premise, not sure the conclusion follows so easily. But, thanks for the post. I got my money's worth. 
.


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