I change my oil every six months, but have resisted using the synthetic stuff. Any thoughts on this?

Also, how often do you all change your manual transmission fluid? My 1999 Saturn SC1 has 133,000 miles on it, and I had the fluid changed just a few months ago, and that was my first time. I bought the car in 2008, when it had 108,000 miles on it.

Check the owners manual for the oil change period on the manual transmission but 100,000 miles sounds about right for manual transmission or rear ends.
The real determination on oil changes is how long the additive package hold up. Truck driver don' t change oil by miles because it can take over 4 gallons of oil. They pull oil samples and send them to a lab that runs a check on the additive package. When the additive package starts to break down, it's time for an oil change. Synthetic oils do tend to last longer but without a test kit, I would advise you stick with the factory oil change period.
The reason for changing the oil is not because the oil wears out. The reason is because the additive package breaks down or the oil is carrying to much grime.

I run synthetic in my 24yo 1990 Olds Cutlass Ciera. Why? Because it is the best for the motor. Which still has only 60,000 miles on it, and I intend to drive the car until the wheels fall off. Rebuilding the suspension in a couple of weeks.

I change engine oil twice a year, spring and fall, not because it really needs it with the low mileage I drive, but I prefer to run 20w50w in the summer and 5w30w in the winter to make cranking a bit easier when it gets down below zero f here.

Your statement about the additives in oil being what 'wears out' is largely true. I have not changed the auto transmission fluid, but I did top it off with a bottle of additive restorer. I think it may have been from Lucas. It replenishes the detergents and thingys that keep gum and sludge from building up and the seals from hardening.

Another thing I might point out about automatic transmissions...sometimes when they act up, the filter has to be changed. Yes, auto trannys have a fluid filter too. It's inside the pan. I had a couple of old high mileage Buicks years ago that when the weather got cold, would hesitate to go into gear in the morning. That's because the filter was clogged up and the cold, thicker fluid would not flow through it readily.

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"Time is simply the mechanism that keeps everything from happening all at once."

The reason for changing the oil is not because the oil wears out. The reason is because the additive package breaks down or the oil is carrying to much grime.

My car's engine oil gets dirty. I drive light miles, but always city stop n' go, never highway.

It's amazing to me that the transmission oil doesn't need to be changed as frequently as the engine's.

Two thing break down motor oil. One is the engine runs at higher temperatures and there is blow by from the rings. Transmissions have oil coolers that allow the oil to reach the optimum temperature and then tend to hold that temperature. I saw a table once from GM and it indicated oil at room temperature would last forever but at the temperature increased, it's life was shorter. That is also the reason why oil coolers have been added to engines.

Automatic transmission can have a shorter oil change period if they are used to pull heavy loads because the temperature may rise above the normal operating temperature. This will result in a burnt smell.

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The reason for changing the oil is not because the oil wears out. The reason is because the additive package breaks down or the oil is carrying to much grime.

My car's engine oil gets dirty. I drive light miles, but always city stop n' go, never highway.

It's amazing to me that the transmission oil doesn't need to be changed as frequently as the engine's.

Two thing break down motor oil. One is the engine runs at higher temperatures and there is blow by from the rings. Transmissions have oil coolers that allow the oil to reach the optimum temperature and then tend to hold that temperature. I saw a table once from GM and it indicated oil at room temperature would last forever but at the temperature increased, it's life was shorter. That is also the reason why oil coolers have been added to engines.

Automatic transmission can have a shorter oil change period if they are used to pull heavy loads because the temperature may rise above the normal operating temperature. This will result in a burnt smell.

If the oil truly has a burnt smell, it usually means you are burning up the clutches with slippage. Not usually from the fluid itself.

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"Time is simply the mechanism that keeps everything from happening all at once."

I like having a tach, even with an automatic trans.

I wish my oil pressure gauge had more numbers on it than just at the bottom, middle, and top. It seems like just above middle is normal for it.

My 94 Caprice was a used police car. It had a transmission fluid cooler and a power steering fluid cooler. The day after I bought it (from a small independent dealer in Chicago) I took it for oil and trans fluid changes.

When I first got the Trailblazer, I kept taking it back for oil changes every 3,000 miles (free under some warranty or other, which has since run out). They told me it was good for about 5,000, but I should let the monthly report from On-Star tell me when to change it. It gives a percentage of oil life remaining (which will be out of sync at the moment because at the last change they forgot to reset the computer).

I have learned not to always trust the low fuel warning light. I have more than once run out without it coming on.

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David
Sitting on my butt while others boldly go,
Waiting for a message from a small furry creature from Alpha Centauri.

In my rig, left for clutch, right for gas and brake

That is the "proper" way to drive.

Errrmm, it is the ONLY way to drive as that pedal layout is universal for RHD or LHD! As I used to say to my pupils that had difficulty remembering the pedal layout "working from the right, it's as easy as ABC, accelerator, brake, clutch".

My point -- not to sound technically-elitist -- is, that, perhaps, cars are
being designed for the least-technically-inclined. And, folks who understand
at least the basics, are being shunted off to the side.

It's not quite like that Jim! Back in the early 60's when I first passed my test, cars were so simple that a 10 year old could work on one (and they did!). At that time in the UK there were still some pre war push-rod sidevalve engines about although OHV and OHC were becoming the majority. You opened the bonnet and you could get to everything, plugs, points, carburettor, filters etc. In those days we changed the vegetable based engine oil every 3000 miles, used flushing oil as well, and used different grades for winter and summer, But quite soon, 20W/50 multigrade mineral oils were coming in that lasted 5000 miles.

EP80 oil for the gearbox, and Hypoy90 for the rear axle Diff. The Champion L10 plugs were changed every 10,000 miles when you did a decoke. Set any car to 25 thou plug gap (35 thou for fords), points at 15 thou, timing at 10 Deg BTDC, and a nice blue spark on the Colourtune plug, and any car would run quite happily. You could re-jet a carb to get some extra performance.

People took pride in owning a car and most men would do simple maintenance themselves. All you needed was a toolkit with a set of combination spanners, feeler gauges, oil filter wrench, spark plug spanner, brake shoe adjuster spanner, colourtune. The more geeky of us into de-coking, had a socket set and a torque wrench for the head nuts. It was a standard requirement before any trip to check the tyres, petrol, oil, and water. And every so often the brake and clutch fluid.

But, technology moved on, cars became more sophisticated, Fuel injection came in, electronic ignition, engine management chips, diagnostic machines, instrument panels had a plethora of warning lights. You open a bonnet of a modern car these days and you just shake your head and close it again. Plugs last 60,000 miles, good job, ever tried finding one? You could change the old air filters in seconds, these days they are hidden away somewhere in many feet of ducting. Modern multigrade synthetic engine oils last for 20,000 miles or 2 years, with no sludge in the sump. Good job really as that is where front wheel drive cars effectively have the gearbox!

And also it has to be said that on the human front, drivers became lazier. It isn't seen as a privilege to own a car these days, it is just taken as a simple life convenience like running water at a tap. Ask a modern man to get his hands dirty and you'll get a pained expression. Also there is some truth in the accusation that car manufacturers deliberately design cars to be hard to service or repair by the owner, so that they have to be taken to a garage, or preferably a main dealer, for almost anything these days. Look at these labour charges! Garage hourly rates.

Jim is partly right in his assertion that the average chap with some knowledge is at a disadvantage these days, but there are other influencing factors. A large proportion of cars sold are fleet and company cars, where repairs and servicing costs are written off to tax by the company bean counters. That gives the car manufacturers the freedom to ensure that their Modus operandi continues. I counter that by using a friend of mine to service my car. He is a main Agent BMW mechanic who also does private work, and at a very reasonable rate.

But this could very easily get into a political discussion, which will have to be elsewhere, so I will leave it at that, on what is supposed to be a lazy Sunday!

When I rebuilt the engine on the car I learned to drive on, I stood in the engine compartment with the engine to work on it. That is no longer possible with a modern car...

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BOINC WIKI

I try for at least a couple of oil/filter changes, a year. With 15K miles/yr.,
average, it's not enough.

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I try for at least a couple of oil/filter changes, a year. With 15K miles/yr.,
average, it's not enough.

I change every 10K but I use a full synthetic oil.

I try for at least a couple of oil/filter changes, a year. With 15K miles/yr.,
average, it's not enough.

I change every 10K but I use a full synthetic oil.

Every 10K I do a major maintenance, every 5K I do a small maintenance. I always use half-synthetic oil, best for my type of car. (Toyota Yaris, unleaded gasoline)

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rOZZ
Music
Pictures

I try for at least a couple of oil/filter changes, a year. With 15K miles/yr.,
average, it's not enough.

I change every 10K but I use a full synthetic oil.

Every 10K I do a major maintenance, every 5K I do a small maintenance. I always use half-synthetic oil, best for my type of car. (Toyota Yaris, unleaded gasoline)

I'm glad you brought that up. I've heard two schools of thought about mixing synth with regular. Some say once you go to synthetic, you can't go back, but other people have told me it's perfectly fine to mix.

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The mind is a weird and mysterious place

I try for at least a couple of oil/filter changes, a year. With 15K miles/yr.,
average, it's not enough.

I change every 10K but I use a full synthetic oil.

Every 10K I do a major maintenance, every 5K I do a small maintenance. I always use half-synthetic oil, best for my type of car. (Toyota Yaris, unleaded gasoline)

I'm glad you brought that up. I've heard two schools of thought about mixing synth with regular. Some say once you go to synthetic, you can't go back, but other people have told me it's perfectly fine to mix.

All BS. There are mixes sold by Syntex with a mix of synth and regular oil out of the bottle. They market them as mixes.

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"Time is simply the mechanism that keeps everything from happening all at once."

I try for at least a couple of oil/filter changes, a year. With 15K miles/yr.,
average, it's not enough.

I change every 10K but I use a full synthetic oil.

Every 10K I do a major maintenance, every 5K I do a small maintenance. I always use half-synthetic oil, best for my type of car. (Toyota Yaris, unleaded gasoline)

I'm glad you brought that up. I've heard two schools of thought about mixing synth with regular. Some say once you go to synthetic, you can't go back, but other people have told me it's perfectly fine to mix.

All BS. There are mixes sold by Syntex with a mix of synth and regular oil out of the bottle. They market them as mixes.

Valvoline(and probably others) push recycled oil, which I've been using, but at first it seemed weird to me. I was worried it was "worn out" oil, but as has already been said, it's the additives that wear out, not the oil.

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The mind is a weird and mysterious place

Next to Seti, the most I know is about my cars.
I have driven them to death, I knew why, and I continued to do so.

I have killed more big block Buick 455s than anybody I know. They just could not properly oil that number 8 rod.

That was a long time ago now. Nowadays, I drive a 24yo Olds.

I am not sleeping with the fishes just yet.
I have a 1985 Maxda RX7 in the driveway.
Sleeping for now. I must charge the battery before winter freezes it.

I have always loved my automobiles. And driven many of them to an early grave.

Could tell ya lots of stories about my cars and me.

I could fill pages with them stories...................
All true, mind ya.

But me and cars have had a long history....LOL.

My dad and I once had almost this same conversation about a '60 something Dodge Charger with the dealer. It was a prime, low mileage specimen. Coke bottle Charger. Hemi.

I was 18.

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"Time is simply the mechanism that keeps everything from happening all at once."

I go way back on cars too. I bought my first car at the age of 12. A 1955 Chrysler New Yorker. It was a boat but it was powered by a nice big hemi. I stripped it to a dirt track racer and drove it around the back yard. I had a big back yard. Since then I have rebuilt around 20 engines. My favorite was a BMW. Ferrari was not fun, too many variables. The BMW the parks looked like they were made by artists, not engineers. American engines were functional. After market performance parts were great but not so much the stock.
I drive a lot. My BMW I drove for 750,000 miles. I have had 3 Jeep Grand Cherokees each with over 250,000 miles. My newest car, 2 year old Audi has over 100K already.

I try for at least a couple of oil/filter changes, a year. With 15K miles/yr.,
average, it's not enough.

I change every 10K but I use a full synthetic oil.

Every 10K I do a major maintenance, every 5K I do a small maintenance. I always use half-synthetic oil, best for my type of car. (Toyota Yaris, unleaded gasoline)

Full sythetic oil is the best no matter which car and it last at least 20K.
Its wasting money if changes earlier.

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With each crime and every kindness we birth our future.

If I may insert another item, in our auto discussion: Miles/gallon (K's/gal).

This is not boasting, or complaining, just for general info. -- my 2009
Ford Focus (5-speed, manual) gets 40mpg, highway, to Augusta, Maine (rolling
terrain), but drops to 36mpg on a round-trip to Burlington, Vermont (through
the Green Mountains). It has about 67K miles on it, and I don't know how
many, total it'll have, when it should drop dead.

For that, the best car, thus far, was a Ford Escort (I forgot the year.) --
It got 36mph, highway, and lasted 250K miles, before demising. I was not
kind to it, on oil-changes, however.

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I think it depends a lot on the kind of use that a car gets Mike. I drive about 4000 miles a year, and all of that is fast motorway and main road work. So I can get away with the BMW synthetic long life oil, and it will last 2 years or 20,000 miles whichever comes first. Your driving is even faster! A car that is used for stop/start city driving all the time will need it changing a lot more often.

It goes without saying that the cleaner the oil the less wear and tear on an engine. The by products of combustion are various acids and water which get into the oil, that is why motorway driving will help to burn/boil some of that off.

Nope, doesn`t matter.
I made first oil change after 5 years and 20K.
The oil was still clear like water.
And i have merely stop and go.
My uncle worked for Ford for more than 45 years.
Most people just waste money changing oil so often.

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With each crime and every kindness we birth our future.

BMW engine`s are constructed a little different.
Valve wiper rings are adjusted to burn a little oil.

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With each crime and every kindness we birth our future.