Ok, here's the deal. I changed my oil some time last year or maybe the year before. I can't remember. Since then, I've gone through a whopping 4 or 5 tanks of gas and driven it around 1,000 miles. When I pulled up the dipstick the other day, it was still gold colored and hasn't even darkened yet.

I'm planning to change the oil before I put it away this year, but honestly I'm wondering why I should even bother. I understand that after a while oil can become acidic and start eating at the bearings, but I'm running Mobil 1, and as far as I know that acidic change only happens with dyno juice.

Since BMW and a couple other manufacturers are shipping with synthetics and their scheduled oil change reccomendation is over 10,000 miles now, I really can't imagine that my oil is causing any problems considering the ultra low milage. Anybody care to comment/agree/disagree?

 

the good old saying "better Safe then Sorry" pops into my head when reading this post

 

The "acid" comes from water accumulation. The water comes from having the engine run but not brought up to full operating temperature, and moisture from the PCV system condensing in the crankcase. The moisture mixes with other stuff in the oil/crankcase, especially sulfur, to form acids.

Oils are formulated with acid-fighting base additives. The ability of the oil to neutralize acid is called its "TBN", or Total Base Number. The higher the number, the better it is able to neutralize acid. TBN varies by oil type, even within the same brand name, so you'll have to look at what your oil specs out at.

AMSOIL makes a synthetic they call Heavy Duty Diesel & Marine with a high TBN. It also has other anti-corrosion additives, and is rated as a gasoline (spark ignition) oil. I use it in the '57 since it sits 6 days of the week during the summer, and pratically all the winter. This oil also has great anti-wear properties.

 

How about a 1996 with 4,176 miles. It's had six Mobil 1 oil changes so far, and not because the oil was dirty at all. Just as 5-7 stated, crankcase acid is not a benefit to bearings, aso I keep changing it annually. It's about due again, just before the winter storage process.