Mineral vs Synthetic?

[VinceF]

I have a new Subaru I plan to switch to synthetic after the 2nd change. I don't put many miles on the car, 3500 in a yr, and mainly highway. I have an 86' Chevy with 81k on it, and planning to use the oil I drain from the Sube in it. I think Synthetics last a lot longer, and with mostly highway miles, don't think it would be used up at reccomended time intervals for a new car, except for additives. My Chevy uses some oil between changes, so figure adding some fresh, and saving the rest to top off would be fine.

I read where Bob says that synthetics don't find leaks like they used to with the new gaskets and additives, but Not gaskets on an 80's car, and to flush an old motor before switching. I picked up some Quaker State Q synthetic and some Mobil 1 synthetic. They are Both thought to be highly refined Group 3 mineral oils, Not true synthetics, and I am wondering if Bob's warnings about old seals and flushing hold true for switching to them in an old car? Seems like since they are compatible with mineral oils, they are basically the same, and the problems wouldn't exist. The Subaru isn't a turbo. If it was I would go with what I believe are True Synthetics, Group 4 or I believe there is a 5. Been a while since I searched for info.

VF

 

[scoobie]

crazy ... i did that for a while several years ago with my e-150 and my ford ltd. the ltd engine turned to toast, and i had to scrap the car. the chevy is still a baby, it shouldn't be using any oil, but if it already is, then start using high mileage oil in it, and maintain it properly. if you want to save a few dollars, change filters every other time, that is a lot safer than re using old oil.

 

[GMFan]

I would not use used motor oil in another vehicle. I'd just buy cheap conventional for the 86 Chevy.

 

[scoobie]

I also have a new Subaru, Impreza NA 2.5 hatchback. In your situation, I would change the oil every spring, annually. Over winter, the oil gets more stressed, so dump it in the spring.
Do the same for the Chevy. DO NOT re use the Subaru oil in the Chevy. Possibly with a high mileage oil the Chevy might even stop using. And for changing oil every 3500 miles, there is absolutely NO BENEFIT to using synthetic oil, you're just wasting your money. Modern conventional oils are excellent. For example, Mobil 5000, or Valvoline, Pennzoil, QS, heck, even SuperTech oil has great UOA numbers, or if you don't mind spending a little more, use semi synthetic oil, but that's about as far as I would go.
Your engine will last exactly the same length of time, no matter which route you take.

 

[ZZman]

A little more info please:

1. Do you drive the Chevy mostly and rarely use the Subaru?
2. How many miles on the Chevy do you drive a year?

One Syn oil change in the Sub a year. That is low cost.....why sweat it?

I agree with others above. Run a good Dino in the old Chevy.

 

[simple_gifts]

Pouring a car's used oil into another car is like using someone else's toothbrush.

 

[demarpaint]

Originally Posted By: simple_gifts
Pouring a car's used oil into another car is like using someone else's toothbrush.


LOL- Good point....Years ago I had a neighbor with an oil burning Chevy van. It was an old junk box but he couldn't afford anything to replace it. IIRC he used about 1 qt/100 miles. I would give him the oil I drained from my E-150 to use. He ran that oil for quite a while.

If you like your vehicle get cheap oil to use, and send the waste oil to the recycle center.

Frank D

 

[FZ1]

No,man. 2 ocis per year. Spring AND Fall.

 

[Steve S]

You will not get any advantages using syn oil in your cars. Why waste your money?

 

[kingrob]

There was a Ford Mechanic I read of that would reuse people's oil in his own car. If an older person running synthetic would come in every 3,000 miles wanting their oil changed as they were accustomed to doing before the conversion to synthetic, he would catch it all in a clean drain pan and put it in his car. It makes me cringe everytime I think about it. I don't care how clean you think the oil is, it really is like wearing someone else's underwear that they've only worn half a day. It's still dirty!

I would run any brand of conventional and change it out twice a year. Even if you only put 1600 miles on it between the changes, if you're running many short trips where the oil isn't heating up enough to burn off the condensation that sets in while it's just sitting, you're oil is getting contaminated. Of course, if you're already willing to run used oil in it, then you're probably ok with changing it out once a year.

 

[VinceF]

The Chevy leaks some oil from the intake manifold gasket, but don't think it accounts for the oil use. Only put 3-4K/yr on the old Chevy, and it was all cold starts and short trips. though in cold weather I let it run a while before shutting, to try to get the temps up. It has a carb, and I was going to try a little crankcase flush down the carb to see if the rings are stuck. I would pull the coil wire and crank it over a few times to suck the flush into the cyls, and let it sit overnite. I had a car with 140K on it, and when I started using it on the road, it was using a qt in 30mi. Tried the flush, and it came up to 550mi/qt. I would stop, and it would drop off, so I did it again, and back up it went. I was buying the flush at Sears, and when the lable changed, it stopped working. I thought the rings were just shot, but Sears doesn't make anything, and the label change was probably a diff mfg, and or formula.

One mechanic friend said he used to get the same results pulling the plugs and squirting in top oil, and never thought to put it down the carb. Another mechanic tried to tell me all I did was get oil around the rings and increase the compression. Flush is like water. He thought he was a good mechanic because his tools and shop were spotless.

Why wouldn't the oil be any good if it was like a clean running car on the highway for 6 mo, and then driven in the city for 6, with a gt added after 6 mo? Aren't synthetics good for more miles than the lesser oils, or aren't the grade 3 ones?

I change the oil in the Chevy 2X/yr, spring and fall. With the Sube I have to keep up the warranty, but that is 7.5mo. I figured with the Sube being FI, and all road miles, the oil would be in good shape, especially a synthetic, even if Grade 3, and just the additives might be depleted, so adding some fresh would replace them. The Chevy is strickley a city car now, not that I took many trips in it, since I became disabled 20yrs ago, long trips wore me out, and I didn't keep the Chevy running as well as I would have, and let things go, since I do all the work I can myself, to have it done right, but it takes me a long time to so not that confident in the car, and a 22yr old is more likely to break down, and I will get it running, but I'll be wrecked after. Have an ignition switch to replace now, and a warped rotor. The Sube being new, I have taking trips, to break the car in, and get used to lots of new things, and a 5sp, that I haven't had in 25yrs.

VF

 

[VinceF]

Originally Posted By: Steve S
You will not get any advantages using syn oil in your cars. Why waste your money?


Don't synthetics sludge up less?

VF

 

[VinceF]

Originally Posted By: kingrob
There was a Ford Mechanic I read of that would reuse people's oil in his own car. If an older person running synthetic would come in every 3,000 miles wanting their oil changed as they were accustomed to doing before the conversion to synthetic, he would catch it all in a clean drain pan and put it in his car. It makes me cringe everytime I think about it. I don't care how clean you think the oil is, it really is like wearing someone else's underwear that they've only worn half a day. It's still dirty!

I would run any brand of conventional and change it out twice a year. Even if you only put 1600 miles on it between the changes, if you're running many short trips where the oil isn't heating up enough to burn off the condensation that sets in while it's just sitting, you're oil is getting contaminated. Of course, if you're already willing to run used oil in it, then you're probably ok with changing it out once a year.


the thing is I only drive the Sube on the road, and don't drive it hard till warmed up, and with FI less gas should get into the oil. Now I only drive it about once a week, but I put 1-200mi on it.

I had a concern about the trans oil, since it is AWD and a 5sp, and the trans shares the diierential oil, and the grade for the rear, has sulfur that can form acids at high temps, and corrode yellow metals, and I assume the syncros are brass and the oil can half the life of them. Subaru wants the gear oil that is good for the rear, so just going to have to make sure I change it when recomended or sooner.

VF

 

[Bill in Utah]

Originally Posted By: VinceF
Originally Posted By: Steve S
You will not get any advantages using syn oil in your cars. Why waste your money?


Don't synthetics sludge up less?

VF
Nope. Esp with 6 month oil changes that you MUST do to keep your 5 year 60k power train warranty in effect. (and if you do a lot of short trips, you should be changing (AND HAVING RECORDS) every 3-4 months)

(Double check your maintenance schedule. The max oil change is 7,500 MILES or 6 months... Whichever comes up first. That is for ALL HIGHWAY operation)

Turbos are much lower OCI period.

I have a Subaru (07 Outback) which just turned over 19k. My factory fill UOA showed a lot of break in metals (which I was happy to get rid of @ 1500 miles) then a conventional oil UOA which was perfect then I went to Syn. My Syn UOA was worst and once I use up my syn, I'll be back to Pennzoil 5w30 conventional (which I picked up 5 cases today for $13 a case)

Enjoy the Subaru!

Bill

PS:

PPS: Plenty of FI engines that dump gas in the oil.

 

[charbaby]

My wife and I have been storing a black 1980 Pontiac Firebird FORMULA V-8 since new and changing the oil anually(about every 500-1000miles). When I drained the oil from the Black Bird(as we call her), I would save the oil for my vehicles that were oil burners and the lawnmower. I don't have any oil burners these days and the mower is newer than what I was using 25-30 years ago so, needless to say, I don't practice this any more. Im putting the Black Bird away this week and she only has about 500 miles on the OCI since I changed it October of '07. The oil still looks very clean but I'll probably drain it later, before year end this way I'll be good to go in the Spring of '09.

 

[Steve S]

Originally Posted By: simple_gifts
Pouring a car's used oil into another car is like using someone else's toothbrush.
Depends whose tooth brush it is.

 

[Steve S]

Originally Posted By: VinceF
Originally Posted By: Steve S
You will not get any advantages using syn oil in your cars. Why waste your money?


Don't synthetics sludge up less?

VF
3500 miles? no look at the uoa postings.. .Your Scoobie is new ? what are your warranty requirements? It is easier to not have to do the it is not the oils fault dance if there is a warranty problem. Your engine will outlive your ownership of the car with dino.