Oil for classic air-cooled VW Beetles

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On a well known VW expert website is the following statement: "We do not sell or use synthetic engine oil for the air-cooled VW as it rejects heat. The air cooled VW depends on the oil to soak up the heat from the head and carry it back to the oil cooler. With the synthetic oil the head temperature goes up and the oil temperature went down. I am doing some testing on a new development in the synthetic engine oil that is advertised to pick up heat from the oil and take it to the cooler without viscosity break down. I will let you know in the future if it lives up to its claims." I'd love to hear BITOGs experts opine on this.
 
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I cant see how a synthetic oil does not get as hot (or nearly so) as compared to a conventional oil.Afterall,most sythetics are just highly processed conventional oils so they start with the same crude that comes out of the ground.And as its passing thru a heater core like oil cooler,its bound to shed heat the same way.In my opinion,its the viscosity thats most important in an AC VW.
 
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First of all I am not an expert on air cooled VW engines but I do thing that air cooled means just that, air cooled. The oil serves to keep the engine parts lubricated so as not to have metal on metal contact and also to carry away heat back away from the heat source. Most experts find that engines run cooler when using synthetics rather than dino oils. Synthetics hold up better and break down less than dino oils under higher heat conditions. Synthetics have been proven in many air cooled applications such as air cooled motorcycles for years. I can not truly think of one reason not to use a synthetic in an air cooled VW engine. I have no idea what they are doing research on with this issue.
 
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Since 1995 (?) the BMW boxer motorcycle engines have had oil cooled heads and been called "oilheads," vs. the earlier "airheads," and BMW REQUIRES synthetic oil in those engines. http://en.wikipedia.org/wiki/Oilhead I think the author of that "expert" article doesn't know what he's talking about.
 
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I have been driving my air cooled VW since 1988. I now have almost 200,000 miles on it and use dino oil as you people call it. Castrol 10W30 every 3,000 miles. No problems. Why waste your money on synthetic oil?
 
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Originally Posted By: homeboymi
I have been driving my air cooled VW since 1988. I now have almost 200,000 miles on it and use dino oil as you people call it. Castrol 10W30 every 3,000 miles. No problems. Why waste your money on synthetic oil?
No one ever said mineral oil won't work in many low stress applications. Having said that it is not a "waste" to use a synthetic oil for their numerous advantages.
 
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Originally Posted By: vintageant
So, Caterham, what oil would you use in a 1970 VW beetle not (yet) equipped with an OP gauge?
It's come up a few times before; there are a few threads on the subject. Anyway, based on homeboymi's experience I would conclude that a high ZDDP oil is not necessary, therefore any 5W-30 syn' should work just fine.
 
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I am not Caterham but currently I have the following synthetics in my current stash: Mobil 1 5w30, Castrol Edge 5w30, QSUD 5w30, Pennzoil Platinum 5w30, and G Oil 5w30. They are all quite acceptable oils, especially if you get them on sale and stash them away.
 
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This is about old AC VWs, right? So without an oil filter, they need frequent oil changes - like 1,500- 2,000 or so. And they only hold 2 1/2 qts, BTW. A full synth is a total waste. Any engine cools itself with the oil, but old VWs even more so. There is an oil cooler in the fan shroud. I was heavily into VWs years ago. Fun and charming, but increasingly not a good platform to start with.
 
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While I am certainly not an expert in air-cooled VWs, what the so-called expert says sounds very wrong to me. The duties of the oil in ANY engine are to lubricate, to seal, and to cool. IF synthetic did not cool as well as dino, I have to believe A) we would have known this a long time ago, and B) there would be issues with synthetic in all forms of internal combustion engines. I'm throwin' the [censored] flag. Wow, can't even use the letters B and S together here....
 
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VW's are partially oil cooled via an oil cooler and fan that forces air across the cylinders and thru the oil cooler. From a different, highly respected VW expert.
Quote:
Since synthetic oil has better heat transfer qualities than dino oil, your internal engine temperatures will be lower. Things like bearings, especially, will not operate at as high of a temperature as a result. The wider range of temperatures that synthetic oil can withstand is well suited for the air-cooled VW engine. With head temperatures normally between 300-350 degrees, synthetic will not breakdown while lubricating the valvetrain components at the heads. The better lubricating properties of synthetic in general will lead to a longer engine life as well. On average, when synthetic oil is run in an air-cooled VW engine, head temperatures stay the same, but engine oil temps reduce by anywhere from 10 to 15 degrees. This is in engines that have all the correct cooling tin in place, and are not suffering from overheating to begin with. Important note: Do not run synthetic to fix a hot running engine. Find the real reason it's running hot, and fix it!
http://www.aircooled.net/gnrlsite/resource/articles/synthoil.htm From a thread at the samba. http://www.thesamba.com/vw/forum/viewtopic.php?t=280293
 
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Originally Posted By: Brons2
Dino 15w40 or straight 30HD, is what I have heard of people running in these motors.
Just because the engine is antiquated doesn't mean you have to use an antiquated oil. Take advantage of todays modern high VI multigrade oils.
 
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I would definitely install an oil pressure gauge. Many old aircooled VWs have a hard time maintaining decent oil pressure and thus heavy oils like 15w-40 or 20w-50 are commonly used. Also, oil temps tend to be quite high which thins down the oil more than a watercooled engine would. A 30 weight might work but my initial hunch is that oil pressure would be borderline once the engine was hot. 15w-40 rotella would be my choice. Also, as Brons2 says, straight 30 is fairly common in these but I don't know if that's for any real reason or just because that's what the 40 year old manual calls for.
 

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Thanks, all! I've researched previous threads, and it appears that Rotella T6 5W-40 would be a good choice. Others recommend HDEO 15W-40, which as you see I'm quite familiar with for my pre-WWII iron.
 

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From the whole article at: http://www.aircooled.net/gnrlsite/resource/articles/synthoil.htm Came this: At Aircooled.Net we recommend that you run synthetic oils in all cases, with one exception: you should continue to run dino oil (and change it every 1k miles) if your car still has the stock oiling system. There is one thing I need to clarify though -- if you are not running an oil filter, there really is no point to using synthetic since your oil is going to become contaminated very quickly. Your engine will still benefit somewhat from it, but due to the higher cost of synthetic oil, the gain of running it before it becomes contaminated is negligible. Oil change intervals range from 1000-3000 miles in the VW engine with a strainer (not a filter). VWoM (Mexico) recommends 1k mile intervals on non-filtered engines; keep this in mind for your pride and joy! But on the flip side, the stock VW engine only takes 2.5 qts anyways, it's not going to break you if you do want to run synthetic!
 
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[quote=ksp7498]I would definitely install an oil pressure gauge. Many old aircooled VWs have a hard time maintaining decent oil pressure and thus heavy oils like 15w-40 or 20w-50 are commonly used. Also, oil temps tend to be quite high which thins down the oil more than a watercooled engine would. A 30 weight might work but my initial hunch is that oil pressure would be borderline once the engine was hot. Also, as Brons2 says, straight 30 is fairly common in these but I don't know if that's for any real reason or just because that's what the 40 year old manual calls for.[/quote Installing an OP gauge is of course the first thing I'd do. The multigrade oils of 40 years ago were quite pathetic, hence the common recommendation of a straight 30wt for summer use.
 
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The VW master mechanic I did my journeymanship with (ok, ok, over 20 years ago) stated that all VW's up to that time run 20W50. I know for a fact that the gas Golfs/Rabbits/Jettas from 1981 to 1988 had this specified, as did the Audi 4 and 5 cylinder engines up that that time. It would not surprise me to see that specified for the air cooled ones either. For some reason, I can't remember what I used in the last air cooled VW engine I rebuilt, in 1992. If you run in colder climates, maybe a 10W40 would be fine, and for an occasional driver whose OCI is measured in months and not miles, 10W30 or 5W30.
 
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