This engine is very easy on oil and your mostly highway mileage is also a good thing. I have a 2000 Regal w/ 3800 Series II, V6.
1/2 qt. consumption in 5K was pretty normal with M1 10W-30 for me.
The Havoline can probably do 5K, but it sounds like you are wanting to extend drains beyond that and not spend so much time under the car.
I don't think it's to late to try synthetics at all.
M1 10W-30, GC 0W-30, and Amsoil 10W30 ATM work well. Adding LC may also have benefits, so doing 10K intervals and longer is doable.
I'd recommend getting the Dyson analysis at 5 or 6K and let Terry guide you from there to optimize.
A uoa will check your engine health and is recommended before extending drains. You will find that proper air and oil filtration is also vitally important.
[ January 30, 2005, 06:14 PM: Message edited by: haley10 ]
1/2 qt. consumption in 5K was pretty normal with M1 10W-30 for me.
The Havoline can probably do 5K, but it sounds like you are wanting to extend drains beyond that and not spend so much time under the car.
I don't think it's to late to try synthetics at all.
M1 10W-30, GC 0W-30, and Amsoil 10W30 ATM work well. Adding LC may also have benefits, so doing 10K intervals and longer is doable.
I'd recommend getting the Dyson analysis at 5 or 6K and let Terry guide you from there to optimize.
A uoa will check your engine health and is recommended before extending drains. You will find that proper air and oil filtration is also vitally important.
[ January 30, 2005, 06:14 PM: Message edited by: haley10 ]