I have used Valvoline oil for many years (non-synthetic) in my accord. Now the car has 118k on it. Should I dare switch to Valvoline's MaxLife or Castrol's GTX High Mileage?

 

I wouldn't switch over, unless there's some specific problem or reason. Not just because of mileage.

 

When I bought my car it had 105k on it. I didn't even know what kind of oil had been used previously, but on my first oil change I used Valvoline Maxfile Synthetic Blend.
You might get different responses here. Personally I see no reason not to switch to it, but not really any good reason to switch either.
I do like Maxlife though. It's inexpensive and I've never had any problems with it. Used to use MaxLife 10w30 but switched to 5w30 about 3 oil changes ago.

In the 2009 Edge I use Motorcraft 5w20 because that is what Ford recommends. I couldn't believe my eyes when I saw the Ford Recommended Motorcraft Syn Blend is about $5 (for a 5 quart jug) cheaper than Valvoline Maxlife!

 

i really doesn't matter, but honda's oil is Mobil 1.... that's what I use... Amsoil is also a very good oil...

 

I use Castrol GTX High mileage w/ one can of RESTORE, and the car runs excellent w/ 204k and idles at a little bit above the 500 rpm mark which makes it nice thats its sipping a little bit less fuel when im waiting in traffic in the city.

 

I tried to figure out the answer by looking at bobistheoilguy.com but there is so many different opinions on that site. I was referred to a high mileage oil by my friend (a real mechanic). He knows that I do my own oil changes and even then he made the recommendation. I just don't put much weight on additives in fuel/oil these days. I wasn't sure about switching over to a synthetic brand because some cars have been known to start leaking oil so thereafter.

 

Hey there,
I work for an auto manufacturer as a test engineer (can't say which). But our powertrain design engineers strongly agree with the opinions in this paper:
http://motorcycleinfo.calsci.com/Oils1.html