As long as you stay with the good name brands you should be good. It is not advisable to switch back and forth over and over (like only buying oil that is on sale or something like that). Fully Synthetics have better detergents in them and that will help clean it out. When you switch over run the first change interval to about 3000 miles to get all the crap out, then go to the 5000k - 7500k interval depending on driving habits with Mobil One High Mileage 10W-30 Fully Synthetic.

 

ok, thanks for the response. My durango has about 87,000 miles on it. should i still use the high mileage? and also I don't drive very much since my work is only about 3 miles from my house. Does that effect how often i should change my oil or still do it at 3000 miles. it will just take me longer to get to 3000 since i don't drive very far.

 

3-5000. Yes switch to HighMileage formula. Send a sample to Blackstone labs to see if 5000 is okay for you specifically.

http://www.blackstone-labs.com/

 

alright. thanks for the help. this site is cool and very helpful. i've learned a lot about my durango.

 

Read all the Oil posts...high-milage, cold weather.

Thought I might add this info request:

120,000 miles D 4x4, 5.9. Outside temperatures hit 120-126 in the summer which is coming soon and will stay long.
Still use 10-30 Mobile One if going full synthetic?

 

Yes, synthetics cause less friction helping your engine run cooler when it gets to 120. That is why they have better wear protection also, less friction means less material being worn away. Most of the heat in the engine is caused by friction, not the burning of fuel.

 

Yes, I would use Mobil One 10W-30 in that engine still. 40W would not have any better protection because of the high shear factor. Just stick with the correct 10W-30 Mobil One Fully Synthetic.

Now in this they make a Mobil One Fully Synthetic "High Mileage" 10W-30 version, and this is what I use. The reason I use this specific version is because it has just a little better formulation for older engines that have worn piston rings, and the lubricant has better anti evaporation and higher shearing properties to handle worn engines, but still has the great protection of the regular Mobil One Fully Synthetic 10W-30 version.

Because you are operation in such high temperatures you are in fact creating more blow by because of the added heat over and above the normal. Because of this I would make sure I specifically use Mobil One Fully Synthetic High Mileage 10W-30 in your motor. This oil is a lot more stable in motors in this type situation which is basically a sever duty in extreme heat.

I specifically use this oil as I have 140k+ mileage on my motor and do a lot of short driving and heavy towing.

 

Can't go wrong with Mobile1. I take the position that if its good enough for Porsche engineers...it's probably good enough for the ol Rango. I used it exclusively in my '96 Indy Ram and the ran like a beast all the way up to 180k miles until I got rid of it...doh. Kind of wish I still had it now.