Thanks for the guidance. The car runs hella strong. I bought it from a coworker so I wouldn't beat up my newer Acura TL-S. Changing the oil is no big deal for me since I have military base privlidges and most bases have an auto skills center that for $2 an hour, I can use the lifts and drain canisters to change my oil in less than 20 min.

Most of the time is spent cleaning the oil that drips onto the block from when the oil filter is removed But, I think I will go with 4K and perhaps switch to the Castrol Syntec. That may be a better route to go with an aging engine and perhaps the syntec blend will keep temperatures a bit lower when I travel.

So with Syntec, I'm thinking 5K mile changes? I use Fram Sure Grip 3593A filters and have been for years? Any concerns with this filter. I know they aren't K&N filters, but it seems to do well.

 

Fram = shite. http://www.bobistheoilguy.com should prove why they are if I remember right. I'd use either Wix or PureONE. They're both damn good filters.

You might not want to go full synthetic since you're around 150,000. Maybe a synthetic blend or something along those lines. I'd go with Mobil oil.

 

I change mine every 4-5k depending on driving conditions. You could probably go every 5,000 without a problem. I don't know much about the validity of the new oils for 75k older engines but that's an option. Service manuals typically state every 3,000 if you are driving in extreme conditions. Highway driving isn't extreme unless you are in a really dusty area of the country.

 

With the kind of driving you do, you could easily go 7500 between oil changes. If you really want to see for yourself, end of oil samples to a place like Blackstone labs who will do an analysis, breakdown your oil's stats, and tell you how much life it has left.

Also teh Fram filters are garbage. Id never use one on my car.

 

If you look at what SAE considers extreme conditions, you'll see that most of what people consider "daily driving" is really extreme condition. IE. Stop and go traffic, etc... Just change it a little after you hit the 3,000 mark but don't let it own you unless you're real anal.

 

Interval depends on driving habits. Driving on the highway, your car gets fully up to operating temp. before the engine is shut off, so condensation and other gunk is burned off, keeping the oil more clean. For you 5k should be no sweat. In fact, in your situation I'd say it's wasting money to change at 3k. Stop and go driving, or getting in and driving only a few miles then shutting off the engine makes things dirty quicker.

Inspect the old oil when you are changing, to see how it looks. That will tell you more than anything. Heck, Honda suggests 10k on my Accord, and 5k for severe conditions.

 

Eh I change mine every 5-7k and don't use synthetic, and the oil comes out of the engine looking the same and having very similiar viscosity to brand new oil. I've gone 9k before and it doesn't visibly or change viscosity very much. It all depends on your car and how tight the seals are I think.