Detergent or non detergent in '74 beetle

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Before anyone gets upset, I did a search on VW beetles here and just read 81 threads. I did learn a lot, but clearly there is not a strong consensus in the best oil for a stock air cooled VW.

All my manuals say to use a straight 20 or 30 oil, but those manuals are also 30 years old, and I assume that today's oils are a bit different then those of old.

A friend told me to use only straight 30 non detergent oil, and that detergent oil will ruin a VW air cooled engine.
This bug will probably be driven some during the cold Buffalo NY winter. I know that I need to change frequently and to clean the screen.
I know that "air cooled VW's" threads have been beaten to death here, but in everything I read here nothing was said about detergent oil ruining a VW engine.
I'm no expert and many of the threads here are beyond my understanding, but I just want to use the right oil and do the right thing.
Thank you in advance for your kind help.
The bug is nice, been working on it for a few months, I'll try to post a pic.
Respectfully, Frank D.
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You definitely want detergent oil.

The real question should be do you want streight 30 or do you want a multi-viscosity oil. I suspect that in your air cooled engine you would want 20w50.
 
Welcome, Frank! I'd guess you'd have a pretty hard time finding non-detergent oil these days, and detergents are a good thing, so go with a good quality, modern oil. The manufacturer probably recommended straight weight oils because the multi-vis oils from 30 years ago weren't that great. Today, however, a solid 10W-30 (like Havoline) will do a Beetle good--easier cranking in cold weather, but still able to meet the desired 30-weight warm viscosity.
 
If I had to pick an oil for winter for this car, it'd be SUPERTECH Synth 10w-30, a thick 30 w/A3 rating and seal conditoners. Any HM oil would be nice to the seals.
 
I run a 30w Chevron Supreme in my 4 cyl '67 aircooled and I have also used Chevron Delo 15w40. Lots of guys use 20w50 also. I wouldn't recommend a synthetic in a older engine build, lots of little gaskets in pushrod tubes and head fasteners that have the potential for leaking. I would recommend a high-mileage oil in any of the above. You don't indicate what you use now, how many miles on it, or whether you have an oil leaks...
 
I've had a lot of engine experience with flat 4 VWs.
If the engine was only run on a non detergent previously, then continue. That would be hard to believe, though.
Detergent oil is the way to go, for sure.
Synthetic oil is great for that engine with it's very hot localized regions, but you have no filter, and have to change it very often, so I vote for conventional dino oil. 10-30 Havoline would be as good as any, and better thanmost.
 
How much really cold weather do you see ?

If it's not much, then I'd suggest Delo 400 as per bdleonard.

You'll be using oil changes instead of filters to remove particulate matter.

If you want a synth, the Amsoil HD 30 suff is a straight 30, with pretty good cold performance. Or Delvac 1.
 
I had a 68 while in High school. Ran Castrol HD30 in it. Fun project cars.
Nowadays knowing what I know I would probably run sometihng stout like M1Truck and suv(5w40) in those hot running arir cooled engines.
 
After several earlier models I bought a '72 new VW with the air cooled engine. I used GTX 20W-50 at my mechanic's suggestion. At 101k miles a valve stem broke. I asked my mechanic to mic the engine parts for wear information. I wanted to know the real condition of the engine other than the broken valve stem. He told me that all mic'ed parts were within factory specifications of the engine when new. After the repair I drove that car another 200k miles with GTX 20W-50 before I sold it. It was running as well as it ever had and still wasn't needing topups for the 3k mile OCIs. I'm in Florida so the 20W-50 was suitable for year round use.
 
Hey neighbor. I don't have any comments about the oil, I just want to ask why you would drive such a sweet oldie through all the salt and sand of a western NY winter? Please don't!
 
Wow! I can't believe how many quick and helpful responses in just one night! This is an active forum!

I'm sorry I did not post more specifics. The bug has 122k miles on it, and I believe it has had some engine work done on it. My wife and I had a bug 20 years ago, and recently got back into them. I'm learning more every day on how to work on them. I definately will do oil changes very often.

twb- You are so right....I don't want to, and hopefully won't, I'm still struggling with that. I bought this for my 16 year old son, it is his first car...hopefully I can pick up a winter car for him.

Thanks again!

Frank D.
 
Back in the '70s in England I had a friend who was a VW mechanic. He used to buy older, rough-running VWs cheap and then just drive them to work every day, and change the oil once a week (He got the oil 'free' at work) Detergent multi-grade oil, I think it was Castrol. After 6 - 8 weeks, they'd be running like sewing machines and he'd sell that one for about twice what he paid for it, and buy another 'rough runner'...
So I'd say a good modern detergent oil is just what an old air-cooled VW needs.
Personally I'd try Delvac 1300S 15w40 Dino and give it a few short say 1000 mile OCIs...
 
While those old manuals specified a "straight 30 weight" oil, I believe the assumption was that it be a "heavy duty", aka, high detergent oil. Given that aircooled engines are harder on motor oils than liquid-cooled engines because of hot spots from uneven cooling, you should really consider a 30 or 40 weight "SL" detergent oil in your bug. Millions of bug owners managed to start their cars in winter-time north east with 30 weight during the height of the bug's popularity. (Germany's pretty darned cold, too, during winter.)
 
I bought a new Beetle in 1968, and the owner's manual called for detergent oil, 30W in summer and 20W in winter. I used Pennzoil in it - dino of course in those days - and it served me faithfully for nine years.
 
The owners manual for my 1968 calls for 20W-20 in the winter and 30 in the summer, HD (detergent) oil. In the old days I ran Castrol XL 20W-40. Today, its Chevron Delo 400 15W-40.

Pull the rocker covers (you need to do a valve clearance adjustment anyway) and look for sludge. If non-d oil was really used, and not changed very often, there would be lots of evidence right there.
 
Nice car. When I grew up in Minnesota, VW bettles semmed to be very rust prone. My dad had a 73' super beetle which he gave to me as my first car and the floor boards had big holes in them and other parts of the car were rutsted out also. Dont ruin it by getting salt on it, it will stay in places that wont get washed out by washing it. I would use what VW calls for in the summer months, a 30w. My choice would be shell rotella 30w. In the winter if you could find it I would use shell rotella 10w30. Air-cooled VW's dont like to be over revved in stock form at all, if you do it the case gets hammered and you open up and distort the main bearing clearences and the oil pressure goes bye bye permanently. VW's have a oil cooler in the shroud and the oil doesnt get as hot as people would think when the oil thermostat is actually there controlling the flaps to it like it should.
 
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