VW Air-Cooled

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JR

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Michigan born but my heart belongs in dixie
Hello, My name is Ken. Call me KC. I have a question. I am planning on rebuilding a vw air-cooled out of a beetle in the spring. I know these engines need and like a thicker oil. 30-40wts, 15W-40, 15W-50, and 20W-50. I would like to use a oil that will do best for this engine. I will be driving this car only in the summer. So cold weather, cold starts will not be a problem. I was even thinking a 50wt. Then I seen AMSoil even has a super heavy weight SAE 60. What do you guys think would be a good oil to choose. Also I have a about two cases of Motorcraft Superduty 15W-40, four gallons of Castrol Tection 15W-40, and about a case of castrol syntec 5W-50. Would any of these be good. I do plan on frequent oil services. That is because of the heat of the engine and because it will be summer 60-70 degrees maybe a few 80+ days. I have to go. Thanks for the help.
 
KC,
That Tection should do you well...As I remember, the air cooled flat 4 only has a coarse screen for a "filter". I'm thinking the added soot carrying capability of the diesel oil would keep dirt in suspension a little better until change time.
 
I have a Beetle and I run Mobil 1 15-50 in it. My engine is from Mexico and has hydraulic lifters and a spin on oil filter. I'd recommend either a filter pump or tapping the case for full flow while you are doing this.
 
10w-30 actually works well in these engines.. !15w-40 would be great in very hot climates. These engines do not need super thick oils. as long as al the tin is intact, they will last a long time.
 
The piston top ring temperatures on VW and Porsche air-cooled engines is very high. A motor oil with a low flash point(temp where oil becomes vapor) is not good with these engines due to that top ring heat. Look for a 40 weight synthetic with a flash point of at least 420-430.

I have a '86 Porsche 911 and use Shell Rotella T synthetic 5w-40. Fantastic numbers and it keeps my engine running like new. $14 a gallon at Walmart so it will no break the bank either.

good luck!
 
I got me a '67 912 w/ the flat 4. I've run both straight 30 wt and 15w-40 at different times in dino. It can hit 100+ here in Sacramento. Rebuild is about 3 1/2 years old.
 
I would just use the 15W40 you have on hand. Modern 15W40's are far better then old school 20W50 even in an air cooled engine.
 
i have had excellent results with Schaeffer's 5w40 Supreme 9000 in my 1991 964 (911) Cup car...relatively inexpensive to boot!
 
as some else already mentioned, and i will elaborate a bit on, the oil pressure has a role in determining when the oil cooler starts working. if you have too high of oil pressure, youre oil cooler will go into bypass and not cool the oil.

just run any brand name 15w40. also consider tapping the crankcase for a full flow oil filter. this is a very common thing done to aircooled vw's.
if you dont want to tap for a filter, atleast get a magnetic drain plug. its been a while sence i had an aircooled vw. my last one was installed in a tube frame sand rail with no body. i cant rememer if the engine comes with a magnetic drain plug from the factory or not. i know the trans does though.
 
KC,
I've got similar technology in a '65 Corvair. I generally run a 15W-40 in the spring & fall & either M1 15W-50 or a good dino 20W-50 during the hot summer months.
 
Get the performance by pass valve [if it's not already in there]. It opens it's port a little quicker to get oil flowing through the cooler. You can install it in a few minutes.
A shroud that directs air into the inlet area just below the rear window was popular, and helped quite a bit.
An underdrive pulley helps power, but slows your fan, and hurts cooling - think twice about this modification.
Make sure your bellows thermostat opens quickly.
Heavy 50w or thicker oils will really put a drag on the engine - less power and economy will result.
I'd use a 10-30 up to a 20-40, and change it every 1,500 miles or so.
Does 1,500 miles seem too often?
Not with these engines.
 
Straight 30 or 15W-40 HDMO is ideal for those engines. The pressure relief system also regulates flow to the oil cooler, so you dont want to stray too far from the factory recommended 20W-20 in winter and straight 30 in summer.

As was stated above, piston ring area coking is a real problem with these engines, so a high flash point is a must. Every one I have torn down had heavy coking in the upper piston ring lands. Even in synthetic, 10W-30 is less than ideal. The valve train geometry also tends to lead to high amounts of cam/lifter wear and higher ZDDP in HDMO helps with that.
 
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