Just bought a 2,000 Explorer XL with the 4.0 liter OHV and the 5 speed auto. I know the engine's not a powerhouse, but my wife will use it as a daily driver, and I'll use it to commute occasionally too. The X has 64,000 miles on it, and I've crawled under and can't see oil leaking anywhere. This Explorer was a government fleet vehicle (I have reason to believe it was owned by the Geological Survey folks). All fluid levels are just right, so it looks like it was well maintained. Here's my question (finally!)...Is it possible to tell what type of oil (synthetic vs conventional) is in the engine now? I'm very tempted to go with a synthetic, but my dear ol' Daddy always told me that it's best to stick with the same kind of oil each oil change. Don't know why. He just said it. So, having no way to know what's in it now, I'm a little confused about what to do. It'll get a lot of stop and go and a pretty good bit of interstate driving (btwn 70 and 80 mph) and to be honest, I don't change my oil every 3,000 miles. More like every 5 to 6 thousand.

Can I tell, somehow, what's in it now?

What recommendations do you folks have as to what I should run in it? I mean what weight, synth vs conventional, etc. Any help will be appreciated, as I have no owners manual.

Thanks,

Rotorhead.

 

use a good 5w30 synthetic

 

Where you live the Mobil 10w-30 Supersyn would work well year around in that engine at the intervals you have posted .

 

It is very likely that regular dino is in it now. As others have said, it will not hurt anything to change to synthetic. Use what you want to and it will serve you fine. I drive a 99 explorer 4.0 for work. Over 100k and uses no oil. Mobil dino 5w30 every 3-5k.

 

yeah you can switch over to synthetic no prob.

 

Switching to synthetic wont help anything either. One particular moderator on here has had excellent UOA's with havoline I believe. Save your money for more important liquids, like beer!

 

O_O! Preach it brother!

Ahem, whatever you put in will do you fine. As long as it is brand name, and the viscosity is proper for its environment, any oil today will do you just fine. The Dino's of today are great, synthetics absolutely fantastic. I would personally like the added 'assurance' of having at least a synthetic blend oil in my engine (Durablend, Maxlife, etc). Anything I know has a good additive package.

As mentioned...with how warm it would be in your area, I see no reason to use 5W30. You're only adding more Viscosity Modifiers to your oil, rather then having a heavier base oil. 10W30 would be great for that engine. I've not heard of people putting 15W40 in their 4.0's so...

 

Oh really? Look at this!

 

Not all dino 5w-30's use signifigantly more VII's than a 10w-30 ya know . Some just use better base oils as a blending fluid to get to the desired goal .Yep , still VII's but not as many as one would think .

Times are changing . What was true yesterday might not be tommorrow .

I want 5w-30's with vi indexes of 175 or so and poor...pour points .