What weight motor oil should I use on an engine with 150000 plus
You did not say what the year/ make/ model the engine is attached to, but if you have 150,000 miles on it now, just stick to regular oil changes and keep the same oil you are using.Using a heavier weight , like 10/40 or 20/50 instead of 10/30 only make sense of you live in a warmer climate, or have started to notice increased oil consumption. A thicker oil will only decrease your fuel mileage and not give you any added benefits.The only change you may want to make is to use the " high mileage ' line of oils that manufacturers are putting out which have a higher package content of the additives that are normally added.We have 8 restored antique cars, and use regular oil in some, snythetic in some etc. It really depends on the car, engine and type of driving.I have noticed with the synthetic oils that because they are slipperier, they do tend to leak more than in the cars with regular oil in them, so that may be something for you to think about too.You can go to www.valvoline.com/ or www.Pennzoil.com to get more information for your particular situation and just learn about motor oils
At that age you may have to try a thicker weight due to wear on the engine. Look for a thicker grade oil made especially for older engines. Castrol I believe makes a good synthetic oil for cars that have a lot of miles on them.
Use the weight specified by the owners manual. You should only change weights to compensate for extreme temperatures either hot or cold. Mileage doesn't matter.