what would you guys recommend

[kezia]

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.

[ZenithZ24]

Mobile 1. Enough said.

[S_chevy]

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.

[Classicrocjunkie]

Originally Posted by ZenithZ24

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.

[ZenithZ24]

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

[Classicrocjunkie]

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.

[Blue Bowtie]

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.

[SLJ2137694]

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.

[jakegday]

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

[kezia]

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.

[Blue Bowtie]

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?

[Classicrocjunkie]

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?

[kezia]

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

[hink12341234]

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.

[muff34]

Originally Posted by kezia

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.