Switch over oils

i got a 1974 Volkswagen Super beetle and it has only had the non synthetic oil in it and i was wondering if i could switch it over to the 100% Synthetic oil

From what I understand you can switch to synthetic any time ,but once you do you cant go back. (that's just what Ive heard)

Short answer, YES! But you might find your engine leaks more than before.
AND, you can go back and forth, doesn’t matter at all.
For what it is worth, my Porsche mech says 1 quart synthetic, 3 quarts regular give 99% of the benefit of all synthetic.
By the way, your engine likes an oil with ZDDP (zinc) as an additive. Many of the modern oils have reduced or eliminated it to help with emissions and to help keep the catalytic converter healthy. But in your engine the ZDDP helps insure proper lubricant for the valve train. Google “VW Oil Zinc” if you want to read more.

This nonsense gets perpetuated both in beer halls and bingo parlors by people who either can’t read or are too lazy to find things out for themselves.

YOU CAN CHANGE BACK AND FORTH FROM ONE KIND OF OIL TO ANOTHER ANYTIME!! It’s like changing from butter to margarine, unless your doctor forbids butter.

Just use the same viscosity, such as 5W30, or whatever the owner’s manual calls for.
One thing you can’t do (another myth), is to drive a lot longer between oil changes with synthetic, just because the oil is more expensive.

You can if you choose, but I don’t see any reason why you’d want to. You can’t run extended oil change intervals in this car, so you’d be changing expensive synthetic oil every 3K miles.

Seems wasteful to me.

Well, then the two guys who run this web site are wrong cuz I heard it a few years back on their radio show.
It had to do with the seals in your engine and once they are conditioned for synthetic you should not go back, of course that would be if you started synthetic from the start (new car).
I also called Mobil 1 years ago and asked them about the 3000 mile oil change intervals and they said you can run it to 5000 miles just make sure your not buying cheap oil filters. I dont know about you but if I had a company and wanted to sell more oil, why would they tell you that? Of course dont run it longer if your vehicle is still under warranty!

I would agree that you can go longer between oil changes with synthetic oil if we were talking about a modern liquid-cooled engine. The reason you can’t go longer between oil changes is because you have an old air-cooled engine. With an old air-cooled engine you should change the oil every 3,000 miles no matter what you use.

I disagree. Synthetic oil was initially offered to fleet owners as a way to save money. The longer oil change intervals translated into smaller crews in the motor pool. BMW changes oil at 15,000. Exxon-Mobil guarantees Mobil-1 for up to 15,000 miles. These are business owners with a lot riding on these decisions. I’m sure they did their homework and only offered these guarantees after thorough testing. If you can buy a filter that lasts 15,000 miles or change the filter more often, it might make sense. Personally, I change at the manufacturer’s recommended interval and use the recommended mineral oil.

That old air-cooled bug will leak synthetic oil like a sieve…You want zink? Use oil labeled “4-stroke motorcycle oil”.

Don’t be surprised if Tom and Ray blurt crazy sounding stuff now and then. They take advice from their brother. They also have access to a lot of crazy people. Some of the people use this forum only to tell jokes! Outrageous.

Not in my experience. But then that would have been early versions of synthetic. I see no reason that anything has changed that would have made it a problem. Then again I don’t generally see a reason to use synthetic. Like others have noted, I would suggest sticking with the original 3,000 mile oil changes and don’t forget to do the valve adjustments often also. Miss adjusting #3 cylinder and you can lose it.

If you share with us your assumptions for how synthetic will help your car, we can help you understand if they’re valid or not.

How many miles do you currently drive/year?
How often do you change your oil?
What were you thinking synthetic will do for you?

The commercial vs private use is an ongoing debate. I talked to a taxi fleet owner some time back. His cars ran on regular dino oil and went 10,000 miles between oil changes. Why?

  1. The cars are always warm, including the seats. they run virtually all the time and do not incur the nasty wear and contamination from startups and short trips. They also travel at least 100,000 miles per year.

  2. Even if a few blow their engines, it really becomes an exercise in Risk Analyis. Doubling the oil change interval on a fleet to 100 cars provides a hugh annual saving; a few engine failure are small potatos by comparison.

Although car manufacturers classify taxi service as severe and specify frequent oil changes, per mile, it is anything but! Taxi service in New York and San Francisco is hard on brakes and transmissions, I agree. But Aunt Minnie in Mineapolis driving to the 7-11 for her morning paper is much harder on the engine (per mile) than a taxi operator.

Most owner’s manuals state that the specified oil change interval has to be observed, no matter what oil is used in the engine! For a private owner, additive depletion is the key determinant. And most synthetics have no more additives than good regular oil. Mobil 1 Extended Drain has more additives and in the right grade (0W40) is acceptable in modern Volkswagens with the long drain interval, which, as we know is politically inspired. This oil may work for fleet owners, since it allows very long drain interval. But they can also buy regular dino oil with the exta additives. In other words, for most fleet owners, synthetic oil is not the best choice.

The only fleet I know of that uses synthetic (Mobil 1) is the Alaska Pipeline Company which has standardized on Mobil 1 for all their mobile equipment, for obvious reason. They have a wide range of severe applications. They also buy it in bulk since Alaska environmental legislation requires removing ALL used containers from the state!

You are personally realistic enough to use the factory designated drain interval in order to keep your warranty valid.

Finally, synthetics were invented for the jet engine industry , since normal oil lacked the high temperature Stability. From there they found their way into severe applications (hot, cold, heavy loads) for automotive use. My first encounter in the 70s was with Shell’s “Synarctic” , 50% synthetic oil of 0W30 grade that allowed startups at -45F. The drain interval with synthetic is somewhat longer when we have severe service, like high temperatures. The synthetic suffers less thermal breakdown.

Consumer Reports tested a number of oils in New York taxi service and declared all commercially available oils basically the same. They picked the wrong application; synthetics show no real advantage in New York taxi servie; no heavy loads, no severe hot or cold operation. They should have tried Fairbanks, Alaska taxi service instead. A key reason why you will not find many taxis in New York using synthetic oil.

The OP’s air cooled VW engine has large tolerances, and needs a cheap oil with a 10W30 or so viscosity for best performance. I would go to 5W30 in the winter in cold regions. Synthetic oil is a waste of money in an old beetle engine, unless you live in central Alaska.

They don’t need any help to leak like a sieve the do it very well on their own.

His thinking may have been similar to an errant belief I had about air cooled engines. That belief was that since synthetic oil stands up to heat stresses better than conventional oil, it must be good for using in air/oil cooled engines, even if manufacturers don’t recommend or require synthetic oil. I realize now that this assumption was wrong.

Please don’t spread misinformation on what you have “heard”.

I like the risk analysis approach. I do think the stop and go situation is overated in regards to engine life. Can we make a equation? How does driving a car past its scheduled oil change compare with ignoring a intermittent misfire? People do both things. Is it going to turn out don’t do either?

Short trip driving without frequent oil changes is pretty deadly for a car.

I don’t have an equation, but here goes:

  1. We have posters who have serviced their cars well, do mostly expressway driving and get 400,000 miles of service out of their engines with out having to do a ring or valve job.

  2. We have posters who have bought used cars from senior citizens and with only 60,000 miles or so on the clock have severe engine problems. Old people both drive little, make short trips and are forgetful about changing oil.

  3. One really cold start equals 500 miles of normal driving in terms of engine wear.

  4. Toyota had some bad engines with small oil passages and with a long drain interval they sludged up.

  5. You have no doubt heard about the mysterious disappearing oil. A son takes his old mother’s car out for a fast drive of about 80 miles. When he comes back the oil level is down 1 quart or more. He tops it up and does it again; no oil level drop this time. The quart that disappered is water and raw gasoline.

  6. For every gallon of gas you burn you generate one gallon of water. Much of that water (in vapor form) wants to go into the crankcase.

Depending on how long you want to keep the car, you may do the exact right maintenance or just drive it, and when it starts acting up, sell it.

Most maintenance schedules have a good safety margin in them; the oil additives will go at least 40% longer than the change interval. Spark plugs are good for more miles than the manufacturer specifies for change out. However, Volkswagen timing belts appear to have a close to ZERO safety margin, many failing befiore the specified change time.

Taxi firms with hundreds of vehicles can push this perfomance envelope, but you and I with only 2 cars, can not risk that. If the car is under warranty you have to be religious about maintaining it by the book. After that you can start experimenting with drain intervals.