Synthetic Oil

Can anyone explain the advantages/disadvantages of moving to synthetic oil. Is all synthetic oil the same? Do you really get better mileage?

I have a 99 Silverado with Vortec V8 and 35,000 miles and live in Michigan.

Thanks, Brown

Reply to
Brown Weed
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I've switched both my vehicles over, always told myself that if I got a new truck.car I would. Bought a 1 and 2 year old recently so thats the closest I've came. My wife's impala gained a mpg my s10 seems to be the same. The biggest difference I notice is in the real cold winter days, the engine just cranks easier. Since I've started changing all the other oils/grease over is doesn't seem as sluggish on the real cold mornings.

Reply to
Eugene

"theoretically", you should also have less friction, thereby less heat and better lubrication..

Mac

Reply to
mac davis

Number one I think is that it holds up under heat much better. If you really work your engine hard it is well worth the difference.

It has higher shear strength.

Perhaps a little better mileage.

I have used Mobil 1 since it was first introduced. I think it has been well worth the extra cost, which when spread over the life of the vehicle and compared to other expense is not all that much. You can stretch the time between changes too. I found it was far superior when pulling heavy loads on mountain roads.

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A mechanic I know said when he opens an engine he can always tell if it has been using synthetic because it will be much cleaner.

Reply to
HRL

How can you spread out a cost over the life of something that is a repetitive cost for the life of the item? That is like saying that getting 10 mpg is not that much more expensive than getting 18 if you spread out the cost of the fuel over the life of the vehicle. Mobil 1 costs about $15 extra every time you choose it over Dino oil.

I just sold a Honda Accord that had 273,000 miles on it. I bought it new and never used anything but Pennzoil. After that many miles and

14 years it didn't have an oil related problem EVER. It used a quart at about 3000 miles and I always changed it at 5000, for the life of the car. The rest of the car was falling apart around the engine when I sold it but I was able to use that $800 saved (54 oil changes @ $15 each) on other things besides synthetic oil.

My 99 suburban has 124,000 on it now and I use the same oil with the same results so far. Gold wiring in your house would transmit the power more efficiently but is it worth the expense?

I agree that synthetic may be better at lots of things but do you really need better?

Reply to
Bob Muse

The deal with the Honda though is it was never worked hard. A light car that can carry 4 people, maybe 5. I'm running a 4 cly truck and hauling things from time to time so I'm working the engine hard and wanted to have the synthetic as an extra layer of protection.

Reply to
Eugene

If you feel like you are getting a benefit from using synthetic then that is great. I feel like I could get benefits from synthetic too but don't feel like I need those benefits. I regularly tow a 4000 lb boat and a 2000 lb camper in addition to regular city driving with it weighing in at over 6000 lbs. Maybe 124,000 is not yet high mileage but it isn't new either and I don't use oil more than a quart in 5000 miles.

Reply to
Bob Muse

I figure it costs me about $300 extra over 100,000 miles of oil changes. I pay that much for insurance every six months. Never did get any benefit from it.

I regualarly pull 7000 pound trailers over 12,000 foot mountain passes. That is where I really noted the difference. I found that conventional oils were actually evaporating. Open the filler cap and fumes would come out. I don't detect any losses with syn.

After 6000 miles I oil loss is not visible on the dip stick. It still shows full.

I and others who put syn. in carburator fueled engines all noted that we had to turn the idle down. It just seemed to us that there was less friction. Many claim an increase in gas mileage but that is so small that it is hard to detect. Maybe 2 or 3 percent.

Also note that all race cars now use synthetic. The many cars such as the Corvette come with Mobil 1 and is required by the owners manual.

I also found that syn is excellent for air cooled engines such as lawn mowers and snow blowers.

Reply to
HRL

Its not that I feel a benefit its that I hope the wider temp range of the synthetic should allow me a bit more protection. Much like when I swapped my compact spare for a full size spare, or made up and pack a toolkit, spare bulbs and fuses and a spare fan belt. I tore down the 2.5L in my 88 S10 and there was some black burn on oil stuck to some of the parts. My hope is to prevent the little bit of cooking/burning that the regular oil did. I won't know until years from now when this gets a couple hundred thousand miles on it like the old one did. Check back in a few years and I'll post the results then :)

Reply to
Eugene

That's all I use in my air cooled stuff now. Big visible difference in my Harley and lawn equip. . Especially in the small motors, oil stays cleaner twice as long plus most of this stuff is splash lubed with no filtration, good oil is vital. Even with 15-50 (surplus from the H-D 5 qt jug) in the 14 hp tractor it cranks and starts fine in the winter for plow duty.

Reply to
Repairman

What weight do you use? Since B&S usually specify straight 30 I just stuck with the 5W30 weight. The way I look at it the 5W30 Syn is very similar to straight 30 without the VI. It just doesn't get as thick when it gets cold. (For you that don't know about it, Syn doesn't get as thick when it gets cold so it does not need Viscosity Improvers to make what we call multi-grade oil). The 30 weight is specified at 212 degrees F. From what I have heard as the temperature goes even higher the syn does not thin out as much.

I put the 5W30 Mobil 1 in a 1960's era B&S engine on an edger. It suddenly became very easy to start and runs like new.

Now I put in Mobil 1 at the first change. I am amazed at how clean it stays.

I once got a good price on 0W30. Again I don't see any problem with using that weight all year.

Reply to
HRL

"HRL" wrote in message news:XfLoc.233$ snipped-for-privacy@bgtnsc04-news.ops.worldnet.att.net... : What weight do you use? Since B&S usually specify straight 30 I just : stuck with the 5W30 weight. The way I look at it the 5W30 Syn is very : similar to straight 30 without the VI. It just doesn't get as thick : when it gets cold. (For you that don't know about it, Syn doesn't get : as thick when it gets cold so it does not need Viscosity Improvers to : make what we call multi-grade oil). The 30 weight is specified at 212 : degrees F. From what I have heard as the temperature goes even higher : the syn does not thin out as much. : : I put the 5W30 Mobil 1 in a 1960's era B&S engine on an edger. It : suddenly became very easy to start and runs like new. : : Now I put in Mobil 1 at the first change. I am amazed at how clean it : stays. : : I once got a good price on 0W30. Again I don't see any problem with : using that weight all year.

In my 14 hp tractor I use 15-50w M1 year 'round. It cranks a tad slow in winter but no worse than when it was on reg. 30w oil on break in. The surplus from a 5 qt jug used for the bikes oil change is enough for it. In the snow blower it's 5-30w, usually Wal mart goes in that. I'll use whatever brand is cheapest in the lawn equip. Cheap synth is better that no synth IMO Wally world synth. oil is the cheapest and just fine for small motors, it's a matter of if they have it or stock the weights I want. I don't like using zero or 5w stuff in summer in air cooled motors, I like the bottom # to be at least 10 in the multi weight oils as this stuff is hard on oil in the heat of summer. Cylinder head temps run 250 deg. easily in summer. I also use synth. oil in my 2 stroke stuff like the blowers, chain saw and weed wackers. It's all I use in my snowmobiles hence it gets mixed for the lawn equip. . Less smoke, zero spark plug problems. These cheapo crappy motors just won't wear out with synth. oil, both the wacker and blower are

15yr old and going strong.
Reply to
Repairman

I have been trying to get a lubrication expert to tell me why not use 5W in the summer. As I see it the 5W30 might even be better. Maybe I am missing something. My arguement is that perhaps the 5W30 doesn't thin as much when it gets above 212F. The 5W in 5W30 is the viscosity of the oil at 0C (32F). the 30 is the viscosity at 100C (212F). At 0C the viscosity is heavier than it is at 212F. So while warming up both are thicker than when they get hot.

The air cooled engines often recommend straight 30 weight in the summer.

Straight 30 weight has a much heavier viscosity at 32F. If you drew a graph showing how the viscosity changed from 32FC to 212F, the straight

30 weight would have a much greater rate of change, both being the same at 212F. If that were to continue on to 250F the straight 30 weight would be thinner than the 5W30. As I see it the same would apply to 10W30. The 5W starts off with alower viscosity but should be the same at 212F and, if the change continues linear, would have a higher viscosity above 212F.

Conventinal oils using Viscosity Improvers cause problems in hot running engines. A friend had a 4 cyl. where the rings had seized so bad they ended up throwing the pistons away. It was blamed on using 10W40 which has over twice as much VI as the recommended 10W30.

Reply to
HRL

Reply to
tom davin

My sister was running 10-40w in her 4 cyl. Camry, it blew out the oil pump housing gasket right next to the oil pump's pressure relief valve the first winter she had the car (bought used). I blame that on too heavy an oil as it should have been using 5-30w. No probs since I repl. the gasket 80k miles ago with the right oil onboard.

The Harley air cooled motor is the hardest on oil that I know of, it has no oil cooler and the rear cyl. is blocked by the front one. The recommended minimum non synth. oil by them is 15-40 diesel oil for summer use. I feel the low bottom numbers are just not up to high temp. use, the Harley runs a

220-230 normal oil temp in summer weather and at high temps my belief is that it cooks out the additive package designed for low temp use. That's why nobody will recommend or even makes a 0-40, 5-40, etc. oil. The tech. isn't there yet, but I'll bet it's on the way.
Reply to
Repairman

I looked into how they come up with the numbers. Basically what they do for the multi grade oil is to cool it to 0C (32F), put it in a flask and measure how much force it takes to move a paddle through it. The number they assign is the same as assigned to a straight weight oil at that temperature. So a 5W30 at 0C takes the same force as straight weight 5 at 0C. Then they heat it to 100C (212F) and do the same thing. From what I gather, what happens above or below those temperatures is anyones guess. So, The Harley engine is probably way above the 212F in spots.

Next is the addition of Viscosity Improvers to conventional oil. Too much of that stuff is bad news. So you want to keep the spread between the numbers as small as possible. For example GM now says 10W30 is OK but 10W40 is not. It takes a lot more VI to get to the 10W40.

That is where Synthetics are superior. Synthetic doesn't thin as much as it gets hot so they can make the stuff without VI. I can't swear that all synthetics don't have some VI in it.

This site has some good information about oil:

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I notice he also gets into the discussion about VI.

For my Diesel I go with 5W40 Delo 400 Synthetic. Might be good for the Harley too. Red Line would be even better.

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Reply to
HRL

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