I've read the threads about oil and the 5-20W issues (too thin). I have decided to run synthetic in my Expedition as I feel the oil that is thin like this will hold up no problem under extreme conditions if it is a synthetic. Anyway, my question is how often should I change the oil? Some say you can go 5K-7K miles before changing or 6 months intervals. I always heard that you should change the oil every 3K/3 months no exceptions. Whether it is conventional oil or synthetic it doesn't matter as both carry contaminates and this is what leads to wear. Well what do you think? What if you bought one of those oil filtersthat are suppose to last longer?

 

Repeated UOA's by quite a few particpants here in the oil and lube forum have shown where various conventional oils are good for 5000 mile drain intervals.
This in Ford's modular engines, the 4.2 V6, and other engines as well.

I have 165,000 miles on a 2000 4.2 running 10W30 conventional.
My '05 now has 8,000 miles on it and it will be fed the 5W20. I have settled on the Havoline product.

Regarding the "too thin" argument - and I was a hold-out on the 5W20 oil, what determines if the oil is "too thin"? Is it too thin because we think or "feel" it is too thin?
The UOA numbers I have seen here from 5W20 sure look good for an oil that is too thin.

Based on my epxeriences and what I have read here over the last 5+ years, I honestly believe most drivers are better off with today's conventional oils as opposed to synthetic.

If you really want to know what to do, run conventional 5W20 for 5000 miles in your Expy. Send a drain sample in for UOA. If the numbers are good, then there's your answer.
If you want to use synthetic, I can't see running it for less than 7,000 miles. If you want to change it at 3,000 or 5,000, why use it? Conventional oil has been shown to be good for that interval.

You mentioned extreme conditions. What are your extreme conditions? If they are truly extreme then maybe synthetic is good for you.

I'm just crotchety when it comes to synthetic.
I've equated it to squirrel hunting. If you killed 50 squirrels with 50 shots in one hunting season, would you question whether or not your gun and ammo were up to the task at hand?

 

Great response. My conditions aren't that extreme. We do a lot of in town driving and I tow my boat from time to time (about 550 miles a year). I think I will take your advice and just stick with conventional oil. I am having a hard time finding the 5-20W oil. I didn't see any at Wal-Mart except in sythetic form. What do you think about 5W-30? Are the bearing tolerances an issue with the modular engines or is ford trying to maintain their mileage rating?

 

5w20 should be easy to find at walmart. out here the have a whole shelf of it. i have used 5w30 in mine when the 5w20 was not in stock either one will work fine. i posted a uoa on a super duty truck with 7,000 on dino pennzoil 5w20 and the results were very good.