what would you guys recommend

out of curiosity, with 134k miles on my cavi, what kind of oil would you recommend when doing an oil change? i always hear different people say different things. i'm curious to see what you guys think as well.

Mobile 1. Enough said.

if you do your oil change every 3000 mile then just stick with Regular 5w30, I know people will disagree but as long as you change it every 3000 miles you will be ok.

Mobile 1. Enough said.

NOOOOOOO!!... never with that many miles on your car. You should never start to use a full synthetic on a car with over 50k miles. Its molecules are far thinner than conventional oil, which could start to loosen up sludge in your motor and start causing oil leaks from gaskets or the rear main seal. If you started your car on it when it was younger, then by all means keep using it. After the first 3-6k miles on the car, is when it should be switched over to full synthetic if your going to do so.

Kezia - if i were you stick to a high mileage conventional motor oil or possible a syn blend. Do not go full synthetic.

Moblie 1 has a high mileage formula though, wouldn't that work well? Or still no?

I personally wouldn't use it, i've see happen what i've described far too many times. Actually i think my old 2200 was starting to develop a leak at the rear main seal because i switched mine over at 45k. It didn't like to sit over the winter months, which is when i noticed a little 1/2 dollar size puddle right below the rear main.

That's odd. Polyalphaolefin molecules USED TO be actually longer than mineral oil (hydrocarbon) molecules. That's why engine oil blenders add all kinds of polymers to mineral oil to make it suitable for use in an engine. I guess molecular physics must have changed while I wasn't looking.

I suppose I'll have to stop using PAO synthetics in my engines since almost all of them have over 100K miles, and most of them were converted to straight PAO well after 50K miles. I imagine I could ask a real chemist or tribologist about what to do, but the last time I did, the consensus was to go ahead and use the synthetic, deal with the temporary nuisance problems, then enjoy the benefits.

FWIW, don't waste you money on "High Mileage" blends. They are really substantially no different from regular blends. It's mostly a marketing ploy.

Don't take my word for it. Do some research yourself. Instead of anecdotal "data" and testimonials with no basis in quantifyable science, get some hard data. I think you'll be able to discover the reasons that neglected engines leak after switching to synthetic. I think you'll also find out why, and find out that many of them stop leaking once the sludge is removed and seals are reconditioned.

I probably have no basis for these claims, since I don't have a Cavalier. The 134" engine in my half-truck is completely different, since it's mounted in the correct way. I switched that to Amsoil, then Mobil 1 at 84,000. I'm not sure if it's going to leak or not, since it only has 142K on it now. I'll let you know in ten years or so.

Too many people passing on bad info!!! You can use synthetic engine oil from the day the engine is new with no problem. MANY manufacturers use it on the production line in cars such as the Corvette, some Cadillac vehicles, etc. The engines break in just fine. In a properly maintained engine you can install synthetic at any time.

can someone comment on this rumor; i heard that once you use synthetic oil in an engine you have to use synthetic oil for the rest of the life for the engine.....? anyone??


as far as the question goes, ive had my car for the last 50,000 miles, it now has 131,000 on it, since ive owned it ive made sure to change the oil AT LEAST every 3000 miles, i havent missed it once, since i live in an apartment i cant change my own oil, so i just take it to whoever is cheapest, whoever has the special going on, usually its square tire and i just have them use their house (generic) oil, sometimes ill take it to a place and they put valvoline in it, no matter what though she always gets 5w30, and she gets it less then every 3000 miles, and she hasnt failed me yet

wow. so should i just stick to regular high mileage or something? i had no idea there were so many different kinds of oil. on a side note, i drive quite a bit. usually about 60-80 miles a day. and about 150 or so plus on sat/sun. so oil changes are pretty regular and occur pretty often. so i don't know if that makes any kind of difference.

That's 500 miles/week by the simple arithmetic. That means that you should be changing your oil every 45 days/6 weeks. Five quarts of mineral oil and a filter are going to set you back about $14 if you shop well. I get five quarts of Mobil 1 and a Delco filter for under $25. That's slightly better than 2:1 in material price alone. The time you'll save has to be worth something. However, it might be even better than that in your case. If you change to PAO synthetics, use a good oil filter, and monitor oil level and condition, you should be able to change oil at a minimum of 3 month intervals with no problems. If you keep a really close handle on oil contamination (pH, TSS, turbidity, and VI) and maintain a correct oil level, you might be able to extend that to every six or eight months/15,000 miles. If that's the case, using synthetic will actually be far cheaper, not to mention the fuel and wear savings.

Incidentally, PAO synthetics include Mobil 1, Red Line, Royal Purple, and Amsoil. Castrol Syntec sold in North America is NOT a Group IV synthetic. Neither is Pennzoil, Quaker, Valvoline, nor Shell Rotella. They are all Group III (wannabe) synthetics. The closest they ever came to an olefin ester was probably being packed in cartons by someone named "Ester."

As for the other question, once you use a true PAO synthetic (not Group III "synthetic" mineral oils), you can change back to mineral oil at any time. Since using a Group III "synthetic" is really not changing to anything, so it doesn't make any difference.

So, you can change back if you ever want to. Then again, why would you?

Using synthetic off the showroom floor.... While some vehicles come with that yes, BUT i feel those cars were better built and the production company prides themselves on those lines.

Myth or not, i will never do that. Thats why you see all engine builders run synthetic in their motors while breaking in the motor and making sure the piston rings are fully seated.../sarcasm.... Every motor we've built has never failed breaking it in on conventional oil for 800-1,000 miles, then switching over. I personally will not jeopardized a $5,000 built motor and break it in wrong. Why change from what already works?

i obviously don't know much about this so hit me with a nice one word answer of what to buy :)

Use to be a rural mailcarrier that drove 100 miles per day 5-6 days per week and around 400 stops. Changed many tires and many,many brakes and always did my own oil changes. I always used a name brand oil such as Castrol,Trop Artic,Valvoline,etc. Around 160,000 miles my engines would start burning some oil. At that time I would start using a quart of Lucas oil treatment. I tried STP and did not have good luck with it. I sold my route cars(I retired) and each of them had over 220,000 miles on them and they were still going strong. I changed oil every 3-5000 miles. Hope this helps.

i obviously don't know much about this so hit me with a nice one word answer of what to buy :)lol...... don`t feel bad ,there are lots of us here that are now scratching heads. but it does make for interesting reading.:cwm27:

lol...... don`t feel bad ,there are lots of us here that are now scratching heads. but it does make for interesting reading.:cwm27:
Very true. However I just remember the argument of "I know more about cars than you do" with my boyfriend and it makes me feel better :killbarne

Using synthetic off the showroom floor.... While some vehicles come with that yes, BUT i feel those cars were better built and the production company prides themselves on those lines.

Myth or not, i will never do that. Thats why you see all engine builders run synthetic in their motors while breaking in the motor and making sure the piston rings are fully seated.../sarcasm.... Every motor we've built has never failed breaking it in on conventional oil for 800-1,000 miles, then switching over. I personally will not jeopardized a $5,000 built motor and break it in wrong. Why change from what already works?
I'm hooked on a feeling! Isn't there a song about that? I don't care what you feel, facts are facts. After running hundreds of engines on dynomometers using Synthetic Engine Oil, not one of them failed to break in after a minimal run in time. You FEEL the cars are better built? Nonsense! In your few years of experience turning wrenches you have no business handing out what others will consider as fact just because you "have a FEELING".
The following is from "TECH LINK" that is sent to all GM dealers once a month. If you don't like what it says you can argue with GM Fuels and Lubricants.Over the years there has been an overabundance of engine oil myths. Here are some facts you may want to pass along to customers to help debunk the fiction behind these myths.The Pennsylvania Crude Myth -- This myth is based on a misapplication of truth. In 1859, the first commercially successful oil well was drilled in Titusville, Pennsylvania.A myth got started before World War II claiming that the only good oils were those made from pure Pennsylvania crude oil. At the time, only minimal refining was used to make engine oil from crude oil. Under these refining conditions, Pennsylvania crude oil made better engine oil than Texas crude or California crude. Today, with modern refining methods, almost any crude can be made into good engine oil.Other engine oil myths are based on the notion that the new and the unfamiliar are somehow "bad."The Detergent Oil Myth -- The next myth to appear is that modern detergent engine oilsare bad for older engines. This one got started after World War II, when the government no longer needed all of the available detergent oil for the war effort, and detergent oil hit the market as “heavy-duty” oil.Many pre-war cars had been driven way past their normal life, their engines were full of sludge and deposits, and the piston rings were completely worn out. Massive piston deposits were the only thing standing between merely high oil consumption and horrendous oil consumption. After a thorough purge by the new detergent oil, increased oil consumption was a possible consequence.If detergent oils had been available to the public during the war, preventing the massive deposit buildup from occurring in the first place, this myth never would have started. Amazingly, there are still a few people today, 60 years later, who believe that they need to use non-detergent oil in their older cars. Apparently, it takes many years for an oil myth to die.The Synthetic Oil Myth -- Then there is the myth that new engine break-in will not occur with synthetic oils. This one was apparently started by an aircraft engine manufacturer who put out a bulletin that said so. The fact is that Mobil 1 synthetic oil has been the factory-fill for many thousands of engines. Clearly, they have broken in quite well, and that should put this one to rest.The Starburst Oil Myth -- The latest myth promoted by the antique and collector car press says that new Starburst/ API SM engine oils (called Starburst for the shape of the symbol on the container) (fig. 3 and 4) are bad for older engines because the amount of anti-wear additive in them has been reduced. The anti-wear additive being discussed is zinc dithiophosphate (ZDP).Before debunking this myth, we need to look at the history of ZDP usage. For over 60 years, ZDP has been used as an additive in engine oils to provide wear protection and oxidation stability.ZDP was first added to engine oil to control copper/lead bearing corrosion. Oils with a phosphorus level in the 0.03% range passed a corrosion test introduced in 1942.In the mid-1950s, when the use of high-lift camshafts increased the potential for scuffing and wear, the phosphorus level contributed by ZDP was increased to the 0.08% range.In addition, the industry developed a battery of oil tests (called sequences), two of which were valve-train scuffing and wear tests.A higher level of ZDP was good for flat-tappet valve-train scuffing and wear, but it turned out that more was not better. Although break-in scuffing was reduced by using more phosphorus, longer-term wear increased when phosphorus rose above 0.14%. And, at about 0.20% phosphorus, the ZDP started attacking the grain boundaries in the iron, resulting in camshaft spalling.By the 1970s, increased antioxidancy was needed to protect the oil in high-load engines, which otherwise could thicken to a point where the engine could no longer pump it. Because ZDP was an inexpensive and effective antioxidant, it was used to place the phosphorus level in the 0.10% range.However, phosphorus is a poison for exhaust catalysts. So, ZDP levels have been reduced over the last 10-15 years. It's now down to a maximum of 0.08% for Starburst oils. This was supported by the introduction of modern ashless antioxidants that contain no phosphorus.Enough history. Let's get back to the myth that Starburst oils are no good for older engines. The argument put forth is that while these oils work perfectly well in modern, gasoline engines equipped with roller camshafts, they will cause catastrophic wear in older engines equipped with flat-tappet camshafts.The facts say otherwise.Backward compatability was of great importance when the Starburst oil standards were developed by a group of experts from the OEMs, oil companies, and oil additive companies. In addition, multiple oil and additive companies ran no-harm tests on older engines with the new oils; and no problems were uncovered.The new Starburst specification contains two valve-train wear tests. All Starburst oil formulations must pass these two tests.- Sequence IVA tests for camshaft scuffing and wear using a single overhead camshaft engine with slider finger (not roller) followers.- Sequence IIIG evaluates cam and lifter wear using a V6 engine with a flat-tappet system, similar to those used in the 1980s.Those who hold onto the myth are ignoring the fact that the new Starburst oils contain about the same percentage of ZDP as the oils that solved the camshaft scuffing and wear issues back in the 1950s. (True, they do contain less ZDP than the oils that solved the oil thickening issues in the 1960s, but that's because they now contain high levels of ashless antioxidants not commercially available in the 1960s.)Despite the pains taken in developing special flat-tappet camshaft wear tests that these new oils must pass and the fact that the ZDP level of these new oils is comparable to the level found necessary to protect flat-tappet camshafts in the past, there will still be those who want to believe the myth that new oils will wear out older engines.Like other myths before it, history teaches us that it will probably take 60 or 70 years for this one to die also.- Thanks to – GM Powertrain Fuels and Lubricants Group

We all are entitled to our own opinions.

I can throw links from articles too up on here as well to chase my side of the argument.

http://www.mototuneusa.com/break_in_secrets.htm

http://www.ntnoa.org/enginebreakin.htm

Apparently there is nothing wrong with doing it the old way or the new way. So in reality it's up to the owner of the vehicle in what they want to do.

..end story.

Opinions, yes everyone has one. Like Blue Bowtie mentioned, I believe in quantifiable science like the hundreds of engines I was involved with that ran hundreds of hours on chassis and engine dynomometers. These engines ran synthetic engine oil, mostly Mobil 1, and after their various duty cycles were completed, they were disassembled and carefully measured and inspected. Not one of these engines showed signs of improper piston ring sealing or abnormal oil consumption. Some of the engines were run a very short duty cycle specifically to inspect for proper ring seal. So as you can see I am passing on actual test data and not just a feeling or old "Wives Tale" as fact. I know you will continue doing as you feel, just don't pass on feelings as fact.

I will pass on the info as it being up to owner of the vehicle as to what they want they want to use.

Just out of my own curiosity,
Why doesn't GM use mobile 1 in all its cars if its so beneficial?

Mobil 1 is used in vehicles subject to higher underhood temps, high oil temps during normal or probable high performance operation. A synthetic excells in these operating conditions of high oil or component temperatures because it will not form carbon deposits like dyno oil. Carbon doesn't lube very well! :) So to answer your question, from a manufacturing stand point and vehicle use standpoint, a synthetic is not necessary for long term reliability under normal operating situations for many vehicles. It is also very expensive when compared to dyno oil. If a vehicle built without synthetic oil is to be used in a manner that would generate higher than normal temps or used in extremely hot or cold ambient temps I would suggest the use of synthetic lubes in every component including the engine. I use synthetic lube in everything. I will agree that in some conditions it is a little overkill for the use the vehicle is put to but I can afford to use it and in the long term I know that due to it's superior lubricating ability my vehicles will benefit from it. Todays dyno oils are very good, especially compared to what they used to be. A properly maintained vehicle using recommended dyno oil should last a long time.

So like I said in the begining, I personally recommend Mobile 1 :grinyes: So just read through the discussion about synthetic vs regular especially in a higher mile engine and decided for yourself.

what about Royle Purple anyone use that that is what has always been ran im my cavi

i was running it in my cavalier before i sold the motor. Seemed to work good to me, and thats all we run in out fully built motors in the shop after breaking them in.