There are folks here who spend $350+ a year...

 

This is solid information/advice, I agree entirely. Anyone still living by the 3 month/3k mile blanket rule (with no specific regard to oil type, engine type, or usage) is just taking a shot in the dark and likely wasting money. The truth is, unless you're doing UOAs you can't say for certain that the the oil is "done" by any fixed point.

I would never dream of changing oil every 3 months in my garage queens. Talk about a waste! That would amount to about 200-250 miles between changes in the summer and 0 miles in the winter. And waiting 3000 miles wouldn't make sense either, that would take me possibly more than 7 years. Best to find a routine that makes sense for all aspects of the application.

And here is another great post:

More excellent advice/information. Modern factory powertrain warranties are much longer than anything that was available during the golden age of the 3 month/3k mile rule, yet OLMs still allow for much longer change intervals under many conditions. And those OLMs probably report on the conservative side specifically because of these warranties, so chances are you could go even longer with a stock engine and be OK.

 

Good luck with that math........it costs roughly $1,500.00 in total to do an engine swap. Go to the dealership......$4,000.00.

And who keeps a car for a lifetime.....nobody, thats like 50 years. Any engine would need a rebuild like 5 times in 50 years.

My oil changes are $14.95, including a Purolator filter. Takes me 30 minutes in my driveway.
Advance Auto has that sale almost weekly, at least in South Florida and Orlando. Includes 5.5 qrts of Castrol GTX 20w50 or any other weight oil you choose.

Synthetic oils are a complete rip-off and does absolutely nothing extra for protection in a basic engine like a LSx.

And it can be argued that synthetic oils damage peoples engines more....because a lot of people let their synthetic oils run WAY PAST their due periods, because they think its ok.

I spend about $80.00 per year.....and since my engine oil is cleaner than anys oil with synthetic........my engines will last longer. And my 173,000 mile 500 RWHP engine is living, real, actual proof.

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Nobody here is talking about racing engines. I also mentioned earlier in this thread that: This does not include purpose built race engines with close tolerances.

Conventional oil is just as good as synthetic as long as its clean...when they are both clean, they are both the same........thats the whole point of all of this. Again, unless you have a close tolerance serious race engine, synthetic is 100% unnecessary and useless. A factory LSx is very very far from a serious race engine, its nothing more than a daily driver built engine.

If people want to allow their synthetic oil to get dirty as hell after 3,000, 4,000, 5,000 miles....its their choice. They are damaging their internals pre-maturely. My oil when it comes out is exactly as clean as it was when it went in. That is the key to longevity.

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On my previous, bought used, daily driver that I had for 9 years/200K miles and did 8 - 3K mile oil changes on Quick Lube conventionals per year, that's 72 oil changes at $22-$30 per oil change. Most it comes out to be is $2160. And that was overkill for a highway driven commuter car. I didn't know that at the time though. No way I could have bought and installed a new engine for $2160....maybe for $3K to $4K though.

If your oil is coming out as clean at the end of an oil change interval then one of 2 things is occurring. Either your OCI is under 500 miles....or....you have multiple sources of after-market filtration/chemical injection added to your vehicle. And even with more filtration, you can't add back in the chemicals that give you a robust TBN value to start with (ie 8-12 TBN). If TBN old = TBN new, then you haven't put hardly any miles on the oil....or you essentially drove it thousands of miles in a week putting very few heat up cycles on the vehicle.

One of the major oil/car companies recently did a test on a vehicle driven 100,000-150,000 miles or more in just a very short period of time. Mostly all highway miles doing hundreds of miles per day. The OCI's were on the order of 15K-20K miles as I recall. The engine was torn down following the test....and it looked essentially new including measured bearing tolerances.

http://napabigsale.com/

If you want some cheap oil. Go to NAPA in the Chicago or Minneapolis areas on Saturday for a one day sale. Conventional NAPA motor oil for $1.49/qt or Synthetic for $2.49/qt. Not a bad deal. You can change your oil for $10 if you do it yourself.

 

All depends on how you use it. My '98 has the factory engine, never rebuilt, now almost 20 years old. Based on that, something tells me that it won't need 5 rebuilds in the next 30 years. And this car has been seeing annual or biennial oil changes for the last decade, still doing great. It would be crazy to dump perfectly good oil that's only seen ~200-300 miles after just three or six months - especially when none of that was done with short trips, competition usage, or any other harsh conditions.

Part of the value of synthetic is the fact you CAN run it longer, so yes, I would agree that it's mostly a waste if you're going to dump it as frequently as you would a conventional.

That's not really a fair argument. It's not the oil's fault if the user isn't following a reasonable OCI.


This is not really true, and I'm not talking about a race engine either. One benefit of synthetic oil for a street engine is its cold flow abilities - this was touched on earlier by someone else and is correct. A typical daily driven street engine sees most of its wear on a cold start, especially in very cold weather (maybe not an issue in South FL, but certainly a consideration for those of us in the north; it can reach -10 to -20°F in my region.) Synthetic oil of the same grade is superior in this instance.

I used to often go ~5k miles between changes, with synthetic, in my '02 Z28 when using it as a highway commuter. I sold that car with 110k miles and the factory assembled engine was still doing just fine - no loss of power, no strange behavior, no significant oil consumption.

The oil doesn't need to come out "exactly as clean as it went in", nor do I even see how that's possible unless you're changing it every few hundred miles. Some discoloration of the oil doesn't mean that it has stopped doing its job or fallen out of the range where it can protect the engine. You don't have to take my word for it, you can do a UOA (or look at the results of those who have) to see the condition of oil that has 3-5k miles on it in various applications. Sometimes that oil still has plenty of life left in it, all depending on the application.

 

I mentioned earlier that conventional oil at 20w50 will not be so great in very very cold conditions, but if the proper weight is used the engine will be protected on cold starts.......and of course close tolerance race engines might be better off with synthetic oils.

Simply put......if brand new LSx engine #1 keeps its oil clean and uses conventional oil......and the same identical brand new LSx engine #2 keeps its synthetic oil clean (according to whatever the oil manufacturer calls for), BOTH engines will be protected equally. One will absolutely not be better off than the other.

Conventional.....way cheaper.

And we can all use some individual case like your almost 20 year old stock engine, you probably take care of your car better than 95% of people.

I can use my big power race engine that I beat the **** out of for almost 10 years straight and put 173,000 miles on.....Nowhere in the USA have I ever heard of more miles being put on a fully built race motor. But I'm like you, that engine never saw dirty oil, not once. Thats the difference in my opinion. Many other engines just like it blow up, snapped rods, needed rebuilds.....in the 40,000-50,000 mile range, at most. Its the oil, because we can't do anything else to our engines to keep them going longer, except make sure the rune is spot on.

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I can agree that you can save $1/qt on an oil change using conventional rather than synthetic...IF bought on sale. But for my extra $5 (paying $12.50 for 5 qts syntec) vs. $7.50 for conventional, I do get those superior cold flow properties from December to March, when it matters. I don't mind having that extra high temperature margin on the hotter summer days just in case the car does overheat on some unexpected failure. And the synthetic oil is less prone to turn into varnish/sludge if driven under the same conditions as a conventional. You just might have enough extra high end temperature margin to save yourself a new engine in a failure. It all works out to be 2.7c per day over the course of a year for me. I'm fine with paying for "expensive" synthetics for $10/yr extra. And if I want, I could easily recoup that $10 by stretching out a planned conventional 3K-4K mile oil change.....to 3750-5000 miles....which is cake for most any synthetic SN rated oil. Most of the synthetic oil users I know run their cars in the 6K-10K mile range. There are some that bail out in the 4K-6K....but not many...mainly short tripper cars. Most of these 6K-10K and up owners have run numerous cars to the 200K-350K mile mark on the original engines. And as RPM WS6 has suggested they aren't doing this blindly. They've done the research, evaluated hard UOA/VOA and engine condition data to come up with what works for their driving conditions.

But if you want cheap conventionals at $1.49/qt visit your NAPA dealer in Chicago or Minneapolis this Saturday....a one day only sale. The NAPA syntec is $2.49 which is not a bad deal either if you have $5 to spare per oil change. I won't buy this stuff because I'm not a fan of high sodium oils (Valvoline, NAPA, and other boutique brands). Just my preference.

If you aren't buying your conventional oils on highly discounted sales during the year.....then you're paying more money than the people who do buy their synthetic oils on sale during the year. I used to be one of those who did pay $5/qt for synthetic w/o knowing any better. That all changed in 2015 and now I'm in the $2.69 or under club....for as long as the big name oil formulators want to hand out 40-50% rebates.

http://napabigsale.com/

Synthetics aren't for everyone. But there are good reasons where some drivers/some cars would benefit from it. I could understand why anyone wouldn't want to pay $59-$149 for a synthetic oil change at a quick lube place or dealership. Instead, buy your own oil for $12-$25 and bring it with you to use instead of their brand. It is also true that some "conventional" oils are borderline synthetic or semi-synthetic. The difference between conventional oils and non-PAO synthetics has been shrinking for years.

https://bobistheoilguy.com/forums/ub...pics/2466170/2

 

Cold start protection is absolutely better with a synthetic than a same grade conventional in very cold ambient temps, and this (cold starts) is where a typical street engine sees greatest wear. You don't have to believe it, and it probably doesn't even matter much in your climate, but the facts are available if you care to do the research (BITOG.com is a good place to start.)

It's not a requirement for engine survival, but much like your habit of changing oil more frequently than you probably need to (before it even changes color, which is also not a requirement for reasonable service life), using synthetic in cold winter climates offers a little better protection for an engine during those super cold (ambient) cold starts. It is better in this way, and it's not hurting anything, so you are in fact getting something for your money in that application.

 

Guys, the price of oil isn't a problem for me although saving money on an oil change would be preferable. I'm over in Southern California; the temperature here rarely dips below 55 degrees F. And my driving habits are pretty moderate. My '01 Z28 has never seen a racetrack and it's my daily so it spends most of its time crawling in traffic or cruising at 40 mph for short distances.

By the way, I checked my oil color and it was a lightly darkened brown shade. It was not the honey gold color and this surprises me given the fact that my car barely ever reaches high RPM and it's only been 3700 miles...

 

Im not talking about racing engines or built engines with close tolerances, Im talking about any engine (stock or not) in a road race environment.

They are the same until you introduce extreme heat and stress and then the convention oil breaks down much quicker.

I don't think anyone is denying this, and its no argument. You cleaned your engine often and thats what made it last long, not the conventional oil. Im betting your buddies didn't take care of their engines like you did so thats why they failed before yours, regardless of oil choice.

 

INERNY, there are variations in the level of protection and detergents used with the types of conventional, synthetic, and mix conventional/synthetic motor oil brands out there. You have to decide what you think is best. I am probably wasting money every 3-months on the top tier signature brand of synthetic motor oil rated for one year change intervals, but with crème de la crème rankings against named competitors and loaded with anti-wear additives, anti-friction modifiers, and long lasting detergents and dispersants that give the one year change interval rating, I am willing to spend the money! Plus, I am a "preferred customer" so I am given discounted prices for my continued business at so much per year!

Just to prove a point, I drive my Trans Am in winter, and I have had my car sit an entire week in subfreezing cold with a likely drained battery, and my car always fires right up with no hesitation. There is still a fine coating of this oil on the cylinder wall when I start the car, and it never hesitates, unlike my father's car where he buys dirt cheap conventional oil and it requires a few times to crank it up! I am a firm believer and I stand by my synthetic motor oil.


Keep in mind, some of these guys who have posted comments have dedicated racing cars that are not daily drivers and are only taken out for the spring/summer seasons. Now, I believe, I am not 100% certain, but the cheapest of motor oil, the stuff you can buy at dollar general for a buck a quart, has no additives whatsoever, no detergents to keep your motor clean, even with strict oil changes of 3-month intervals OR LESS! I can't guarantee that this dirt cheap conventional motor oil will help keep your motor clean, even with frequent oil changes. However, with better name conventional oil brands with stated detergents added, you should be safe!

When I change my motor oil, it is a dark syrup brown color. This should be reason enough to change your motor oil, it is dirty, it has microscopic carbon build-up and it WILL continue, and these microscopic carbon atoms will slowly and gradually start to wear away at the mechanical parts of your motor, despite the motor oil providing lubrication, the carbon atoms will be rubbing and abrading the mechanical parts. Furthermore, with minute amounts of unburned gasoline also mixing with the motor oil, the motor oil's chemistry starts to change to become more acidic. Even though the one year change interval motor oils are supposed to be modified to combat this acidity, they can't dissolve and remove the carbon atoms floating around in unchanged motor oil, not even my top tier synthetic motor oil. This is why you change it every three months.

For those who argue that it's insane because most people don't hold on to cars longer than five or ten years, I have to say to them, it must be nice to be rich! Also, you can call me a sentimental guy, but I love the styling of my 1997 Trans Am, more-so than the new Corvette Stingray with it's really fuel efficient and powerful motor. Besides, my LT1 motor with MagnaFlow cat-back sounds a lot better cruising around town than the Stingray on it's four-cylinder mode. So, if you won't hold on to your car like the few of us who will, at least leave the motor in good shape for the next owner, okay? I am doing my part to keep my American-made synthetic motor oil supplier, and workers, in business, and I proudly recycle my used motor oil every 3-months!

 

Been running once a year oil change with Amsoil and engine has 110,000 on it (got the car in 2005). My DD is a Honda that says 10k mile oil changes in the Owner's Manual so it gets once a year oil changes as well and has 95k on it (got it with 12k miles 5 years ago), so I don't see any reason to stop now lol. Oh and I drive about 15k miles/year total.

 

Crawling around at low rpm can be more abusive to your engine than tooling around at higher rpms. Idling and crawling tend to lead to more fuel getting in the oil, which uses up your add package. So I'm not surprised you'd have dark brown oil at nearly 4K miles. Steady state driving at highway speeds at 2200-3500 rpm is relatively easy on the engine oil. My daily driver spends most of its time at 1300 to 1800 rpm on shorter 4-10 mile trips, which is severe service imo.

Here's some benefits to synthetic oils. Each person can value them as they like.

• Better low- and high-temperature viscosity performance at service temperature extremes.
• Better viscosity index (VI).
• Better chemical and shear stability....which means holding viscosity longer between oil changes....very important in ATFs.
• Decreased evaporative loss (noack)
• Resistance to oxidation, thermal breakdown, and oil sludge problems.
• Possibility to extended drain intervals, with the environmental benefit of less used oil waste generated.
• Improved fuel economy in certain engine configurations.
• Better lubrication during extreme cold weather starts.
• Superior protection against "ash" and other deposit formation in engine hot spots (in particular in turbochargers and superchargers) for less oil burnoff and reduced chances of damaging oil passageway clogging.
• Increased horsepower and torque due to less initial drag on engine.
• Improved Fuel Economy (FE).

 

I spend most of my time driving at low RPMs...gotta love that rush hour traffic. Anyways I've been running synthetic before this and it hasn't given me any issues so far. I guess I could stick to it.

 

Don't worry my car is gonna be a keeper as well! She's a low mileage queen!!

 

It's not really about the replacement cost of the engine, but the net present value of the depreciation of what is installed in the car currently matched combined with the oil/change maintenance costs over the life of the engine. Installation costs are instantly sunk when a part is installed and have no real value.

I have always wanted to do the math, though and just did. I will spare everyone the economics discussion, but I will retract my earlier statement. I found that if I changed my oil every 3000K miles vs. when my oil light went off, then the additional maintenance investment I would make over the life of the engine (200K miles) would be worth around $1500 to me at the point I purchased my car. If I were to change my oil every 3 months, then it would be worth $3500 to me at the point I purchased my car. Not quite enough to get a new engine... (The economics obviously change the more valuable an engine is vs. stock, how the economy is doing, and how much one spends on an oil change.)

Using this model and plugging in other numbers, basically:
- If one believes that the economic life of this engine is 200K miles and that changing oil more frequently than the oil light indicates will guarantee that the engine will last 200K miles vs. 140K miles, then one breaks even. (If the engine lasts longer than 140K using the oil change light, than the more frequent oil changes waste money.)

 

I hope we helped you with this question!

 

Just read through all this. My 2 cents...
I grew up with the "every 3,000 miles" directive. But that was a holdover from back in the day. Today's oils are so much better that changing it every 3,000 miles is both a waste of money and a pollution machine. The reason no one tells you this is because big oil and all the shops are making big money on all the old-timers and the uniformed who bring in their cars every 3,000 to swap out perfectly good oil with new oil. In fact, California tried (don't know if it passed) to make a bill to stop this 3,000 mile nonsense:
https://leginfo.legislature.ca.gov/f...201520160SB778

FWIW, I drive almost all freeway and probably 15000 miles a year and I change every 5,000 miles or so (synthetic) and my oil still looks decent and my oil change light never comes on.

Thank you wssix99 for the awesome math.

 

I didn't really share the economics formulas. They are pretty deep, but I am happy to if anyone is interested. I would have started another thread if they showed anything dramatic, but the end result really wasn't very impressive with regard to dollars saved. (ie: I couldn't find a scenario where being thrifty with oil was saving more than half the cost of an engine. That's significant - just not dramatic...)