synthetic oil

What are the pros and cons for synthetic oil, other than the price? Would you guys use it in your vehicle? If not, why?.....thanx in advance....

Reply to
Bob
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The biggest con is price because even though oil may go longer without breaking down it still gets contaminated with combustion byproducts and needs to be changed. If you live in a cold climate where minus 20 and colder happens a lot it is a plus too as well as if you see temps above 100 a lot. Wear wise, modern dino oil is pretty good and changed every 3k miles or so your eninge will outlast your car. (it will last a few hundred thousand miles at very least)

Reply to
SnoMan

And even the "3K oil change" may be dying.

My BUICK manual sez; "Don't change the oil 'til the light comes on" At 5K, I got nervous, and had the oil changed anyway. .... it still looked pretty clean to me.

( I wonder when the light woulld've come on ?? )

Reply to
Anonymous

I use the synthetic and change at 5000 miles too. I didn't re-set the light and it finally came on just under 8000 miles total. they claim this is based on my driving etc, but I feel better using the synthetic if its gonna stretch to that far, and I'm still gonna change at 5k, no matter what the dim bulb says.

Reply to
Jon

I have a 92 Grand Am 3.3. 185k miles. About 2 yrs ago I tried a semi-syn. City mileage went from ~21.3 to ~22.5. I've used full syn for the last year. Mileage went from ~22.5 to ~23.8. The only thing I can attribute the mileage increase to is the syn oil. No other changes to car or driving times, traffic, etc. I've noticed that on my car the full syn leaks out of every gasket. The leaks are not bad enough to fix since I never have to add oil between filter changes. I change filters every 5k miles. The oil coats everything from the valve covers down and under the engine/trans. It will burn/leak about 3/4 quart every 5k miles. Before the increase in gas cost, the increase in mileage equaled the increased oil cost (assuming I changed dino oil every 3-4k miles). Now the gas cost makes syn oil worthwhile.

Reply to
=?x-user-defined?Q?=AB?= Paul

Yeah I went 9K with my monte carlo before the change oil light popped on. Technically if you ran synthetic, you could just change the filter, and if the oil still looked good, just topped it off.

Reply to
Paradox

It is because there was some sludge build up at each seal over the years. With that and seal wear, the tolerances remained fine, and the engine remained tight. Now, with the full synth, all the crud has been flushed through with the detergent additives, leaving the slightly worn seals a little open. either switching to a semi synth, and using something like a millers/wynns leak stopper between changes, or better, getting the seals and gaskets changed should sort out those leaks. Also when running a full synth, you can runa slightly thinner oil than normal to avoid excessive oil pressure forcing oil through seals.

Reply to
NeedforSwede2

I religiously use full synthetic in both my Chevy 2500HD diesel and my wife's Kia Sorento.

Pro's - Better flow at cold start-up; better cold weather flow; higher resistance to heat break-down; more consistant viscosity over time. I change our oil and filters every 5,000 miles.

Con's - Don't let anyone tell you otherwise, but unless you are checking your oil's chemical and additive makeup and suspended particles with a lab test every several thousand miles, you will still have to change it regularly. Every manufacturer that claims extended drain intervals also puts in the caveat that the oil must be regularly tested. Even if you're not having a breakdown in viscosity, oil gets dark from suspended particles of combustion (primarily carbon) that the filter does not take out and will still cause wear. The only sure way to remove these particles is with a centerfuge like we did on board ship, and the oil was returned to an absolutely pristine state.

I won't make any claims as to increased mileage, better lubrication, cooler running or leaky seals because of using synthetics, but for me the extra expense is worth the piece of mind for whatever reason. The truth is a good dino oil regularly checked, topped off and changed will also give you good performance, but I feel better knowing I don't have to worry as much about heat and cold especially with a turbocharger on my diesel. The bearings in a turbo run very, very hot and can break down oil and get coked up easily from the excessive heat (especially on hot shut down), and need good oil flow on cold start up.

Just my two cents worth - Jonathan

Reply to
Jonathan

I don't use synthetics. Price dictates part of it, but I choose not to run oils for long service anyway. I don't think it is good practice. I change oil at 3000 miles, and have had extremely good engine life.

I avoid certain brands of oils that I believe I have seen to cause dirty engines and varnishing.

Synthetics and petroleum refinates are both very good, no doubt.

Synthetics may offer better low temperature viscosity figures. There is still the belief (and possible truth) that low viscosity synthetics tend to seep from weepy areas more than petroleum products. Maybe, and maybe not.

Use what your heart and superstition dictates. Modern oils are good, and you are not likely to make much of a mistake.

Reply to
<HLS

Thanx Jonathan, your post was the info I wanted. I've made up my mind, I'm going to try it. Everything I've read so far says basically that price is the biggest negative. So I have to change it at regular intervals like conventional oil..........no biggy

Reply to
Bob

Bob,

Many auto makers are listing longer and longer intervals for oil changes, and some even have the vehicle tell you when it thinks the oil needs to be changed regardless of mileage. Heck, my truck's "Change Engine Oil" message doesn't come up for at least 10,000 miles based on how the computer believes I drive (last time the message came on it had been almost exactly 10,800 miles since the time before). I change the oil every 5,000 miles, and have to add a half quart at the 2500 mile mark between changes. When I change it it is half a quart down which tells me I'm burning slightly less than 1 quart every 5,000 miles. That is well within acceptable usage.

I think a 5,000 mile change interval is acceptable provided you check and top off your level religiously. I have a friend who changes his synthetic oil on a 10,000 mile interval but still changes the filter at 5,000 miles and tops it off.

Cheers - Jonathan

Reply to
Jonathan

Not really because their are a lot of contaminates in the oil that the filter does not take out and well as some of the smaller particals that build up too.

Reply to
SnoMan

I change my oil at 15,000 km intervals or every 18 months. I now have

355,000 km's on my 89 Bonni and 251,000 on my 94 Safari AWD (yes thats fifteen thousand not 15 hundred) Think what you all want. Yup there is a little bit of crud in there. I had the intake cover off the vortec to change the CPI and saw a little bit O crud.who cares the engine' are still gonna outlast the body's anyways! I have even used my neighbours used oil to do top ups at times.
Reply to
Tim Thomson

This is not without merit. SYN oil has a longer chain molecule by design to make it more "slippery" and it has been known to leak past less than perfect seals that dino oil does not.

Reply to
SnoMan

That works out to 220,000 miles and 155,000 miles respectfully which while a few miles in not overally impresive and easily obtainable on dino oil with regular changes. I put more 220K miles on a toyota in 10 years with dino oil and it ran great whole time.

Reply to
SnoMan

If you only had the upper manifold off, there is NOTHING there touched by the oil so that is NO indication of what's in the rest of the motor.

If you took the lower intake manifold off as well, I stand corrected.

I switched my last vehicle to Mobil 1 when I got the vehicle at 60,000 miles. I kept to 3,000 mile intervals but it usually was a little more than 3 months. I plan on giving my new car the same treatment, except I'll run Dino until 6,000 miles, then go to Mobil 1 and change every 5,000 miles.

Reply to
Mike Levy

I wonder how many cars get scrapped with perfectly good motors ?

I had a Chevy Lumina that started to fall apart at 77Kmiles.

Alternator, water pump, air-conditioner, exhaust system, fuel injectors, etc. etc.

Not only was it dollar-ing me to death, I never knew when it would break down next.

I finally dumped the car.... motor still ran great !

Reply to
Anonymous

I've gotten along for 26 years without using synthetic oil. 304,000 miles & counting using Castrol 10 W 30 with no oil related problems such as leak's, smoking, etc..

Harryface

05 Park Avenue, 29,172 91 Bonneville LE 304,246
Reply to
Harry Face

Yes, the type of usage, maintaince and the frequency of the oil changes plays a bigger role in the life of a engine than whether it is SYN oil or not.

Reply to
SnoMan

What is the word on coking with synthetics vs. regular oil (turbo engines)? It seems there would have to be a considerable difference since the two oils are so different.

Reply to
James Goforth

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