What is the best oil for my Pontiac Fiero Formula v6 engine?

[lilkhmerraider]

I want to know whats the best, and longest lasting oil for my V6 engine. I recently did a tune up and oil change, and I used 10w-40 Castrol GTX. I've heard any 10w-40 will be fine. I want to make my engine and car last as long as possible. Any opinions on what brand or number?

 

[Richard G]

...You want to use "Synthetic in 10w-40.........it offers better friction resistance, and with less friction on moving parts your engine will run cooler. Synthetic also keeps the engine "Cleaner"...expect to pay 2 to 3 times as much per quart over conventional oil.

 

[Oreif]

The Castrol GTX 10w-40 is fine. As long as you do proper oil changes, it will last a long time. Synthetic oils are designed for use in newer engines with tighter tolerences than what the Fiero 2.8L was built at. Synthetic keeps your engine cleaner because it runs thinner. This could have a downside. With the age and mileage on an engine that has used regular oil all it's life, Synthetic oils could cause oil leaks around the end seals.

I've seen numerous cars (including Fiero's) go into the 300K mileage range using regular oil.