Many people have different ideas as to what kind of oil to put in their air cooled VW. John Muir says in "How to Keep Your VW Alive" that detergent oil should not be used. He explains that the detergent oil collects dirt which will cause problems in your oil cooler. My mechanic disagrees. He thinks that detergent oil is just fine. For a long time, I only used non-detergent oil but have since switched with no ill effects to my engine (none that I can detect anyway). So, synthetic or regular? What weight should I use?
Well, the weight will depend on where you live. I learned the hard way that I should have changed the weight of my oil before winter came here to Colorado. I had my starter replaced by my mechanic as I simply didn't have the time. I asked him to adjust the valves and do an oil change while he had it. This was toward the end of the summer when temperatures in my area were over 100 degrees. He used 15w30. The engine ran great until the first cold morning. Then, my car really did not want to start. The oil was too thick at such low temperatures. The strain on the starter was so strong that my battery died trying to start the van. A quick oil change to 10w30 and everything was back to normal.
Do I use synthetic or regular? I use a synthetic but haven't had much feedback from anyone that professes a preference for either. Why do I use synthetic? Well, the summers here are hot and I do a lot of driving over the mountains. High temperatures on the flat lands and the tough chore of climbing the mountains makes me want to have an oil that will not break down if the engine gets hot. Am I buying into marketing? Possibly but the price difference is minor. I usually stock up on my oil at Costco or Sam's Club making the price the same as regular oil at my auto supply store.
What do you use? Any feedback on this oil discussion?