I just purchased a used 2002 EXT w/ 52000 miles. The (private party) seller gave me all the service records...it has been taken care of quite well. About 60% of the 52000 were long highway mileage trips.

I live in N/W Montana where winter temps run -20 to +50F. Summer temps run +30 to +90F. 50% of my driving will be 15 mile (one way) trips into town and back home. The other 50% will be 50 mile (one way) trips and/or 400 mile per day trips.

Engine oil has been Valvoline DURA BLEND (synthetic blend) 5-30 from day one and changed every 2500 miles along w/ the filter change.

QUESTIONS: 1/ Should I stay w/ 5-30 year round or go to 10-30 in summer and on long trips?
2/ Should I go to a K&N Air Filter?
3/ Would a custom 4" dual exhaust system (to reduce back pressure) be worth while?
4/ Original spark plugs are still in place....should I install a new set. If so, what plugs, or should I stay w/ the AC DELCO OE plugs?

Your comments, thoughts & recommendations on the above questions as well as anything else related to this vehicle would be appreciated. I'm 73 & retired and any thing I could do to improve the m/p/g would help the pocket book. Thanks in advance. dtb

1. Keep the 5W30 oil in it. That is the recommended oil viscosity and the engine is fine on it. Synthetic oil is not required in that engine....

2. Up to you but I would save the money and use it to buy fresh paper elements occasionally. Replacing the stock element with a K&N element is not likely to give you much, if any, additional airflow. There is just no magic in the K&N filter media in terms of flow despite what they would have you believe.

Similar to the exhaust, there is no way a K&N filter element is going to help the economy despite the claims. At the fuel economy driving speeds and loads the engine is nowhere near it's maximum thruput so even a very restrictive air cleaner could flow enough air so as to not be the restriction. The fuel injection system is not affected by a restrictive air cleaner anyway as it will just see it as the throttle at high RPM, full load and the fueling will still be correct. Carbs used to run rich if the air cleaner was dirty (due to the "choke" effect of the extra restriction) but fuel injection doesn't care and it will run the same with a clean/dirty/paper/K&N filter element up to the point at high speed/high load that the (restrictive) air cleaner causes power loss due to air flow loss...but the fueling and spark calibration and delivery is still optimum for fuel economy regardless of where the actual throttle is.

3. I would not suspect that you are going to get much out of the exhaust described. The engine will make a little more power on top end with the lower backpressure but that is all. Despite the sales pitch the exhaust is not going to affect the fuel economy. Operating in the "fuel economy regime" the exhaust backpressure is negligable anyway. So changing the exhaust system is not going to help there.

4. Leave the plugs alone. They should be good for 100,000 miles or more easily.


Fuel economy...??? Mods are not going to do much for you. If anything, they will hurt the economy. Keep the weight in the truck to a minimum (hauling a lot of junk around is just excess mass) and run lots of air pressure in the tires. Don't exceed the max inflation pressure on the sidewall but the more air pressure the better the fuel ecnomy. With a vehicle that heavy hard accels and stop and go driving kill the economy.

I just purchased a used 2002 EXT w/ 52000 miles. The (private party) seller gave me all the service records...it has been taken care of quite well. About 60% of the 52000 were long highway mileage trips.

I live in N/W Montana where winter temps run -20 to +50F. Summer temps run +30 to +90F. 50% of my driving will be 15 mile (one way) trips into town and back home. The other 50% will be 50 mile (one way) trips and/or 400 mile per day trips.

Engine oil has been Valvoline DURA BLEND (synthetic blend) 5-30 from day one and changed every 2500 miles along w/ the filter change.

QUESTIONS: 1/ Should I stay w/ 5-30 year round or go to 10-30 in summer and on long trips?
2/ Should I go to a K&N Air Filter?
3/ Would a custom 4" dual exhaust system (to reduce back pressure) be worth while?
4/ Original spark plugs are still in place....should I install a new set. If so, what plugs, or should I stay w/ the AC DELCO OE plugs?

Your comments, thoughts & recommendations on the above questions as well as anything else related to this vehicle would be appreciated. I'm 73 & retired and any thing I could do to improve the m/p/g would help the pocket book. Thanks in advance. dtb

Why did you post this in the Northstar forum? They don't put Northstars in trucks. You'll get better answers in the Escalade/EXT forum or the forum specific to your engine.

very true, your truck has a gm 6.0 liter in it, very good engine too, but not a northstar

and of course if you wanna get rid of it i would trade ya my seville!!!!!! : )

I just purchased a used 2002 EXT w/ 52000 miles. The (private party) seller gave me all the service records...it has been taken care of quite well. About 60% of the 52000 were long highway mileage trips.

I live in N/W Montana where winter temps run -20 to +50F. Summer temps run +30 to +90F. 50% of my driving will be 15 mile (one way) trips into town and back home. The other 50% will be 50 mile (one way) trips and/or 400 mile per day trips.

Engine oil has been Valvoline DURA BLEND (synthetic blend) 5-30 from day one and changed every 2500 miles along w/ the filter change.

QUESTIONS: 1/ Should I stay w/ 5-30 year round or go to 10-30 in summer and on long trips?
2/ Should I go to a K&N Air Filter?
3/ Would a custom 4" dual exhaust system (to reduce back pressure) be worth while?
4/ Original spark plugs are still in place....should I install a new set. If so, what plugs, or should I stay w/ the AC DELCO OE plugs?

Your comments, thoughts & recommendations on the above questions as well as anything else related to this vehicle would be appreciated. I'm 73 & retired and any thing I could do to improve the m/p/g would help the pocket book. Thanks in advance. dtb

1. I would still use the 5-30 oil, but I would change the oil brand to Mobil 1.
2. Yes I would change the air filter for a K&N stock replacement just like I did in my 03 and 05.
3. Not sure about the exhaust..
4. I would change the spark plugs for Bosch +4 Platinum plugs...

But as bbob said, I might be making unnecesary upgrades...

Just my $.02

Mejia

Congrats on your truck. :) As said I would use synthetic motor oil, Amsoil, Red Line or Mobil 1 would be good choices, you can run synthetic oils longer and they do not break down, if you just want to replace the filter element the K&N would be a good choice, if you want a new air intake I would look at Volant or Vararam. I like the NGK Iridium IX (TRI-55) I have used them in my C5 Corvettes and in the Escalade, they last long and offer great performance. You will not see much if any gains in MPG. Are you anywhere near Flathead Lake?