Well I don't care about brand, weight, or cost. I just want an oil that I can use for approx 7500 miles with a fair amount of idle time, and keep any leaky lines and past seals in check. So I am just looking for some expert advice from fellow 4.3 users/rebuilders, so if there is abest option based on what ive stated, please advise.

 

The only way to know if an oil can go 7,500 miles in your vehicle is to have a used oil anlysis done by a firm such as Blackstone Laboratories, but I doubt if any conventional oil will do that.Based on your stated goals, I would recommend Motocraft High Mileage Synthetic Blend Motor Oil.

 

Riddle, I have read through hundreds of UOAs' and know how various oils perform on alike Vortec engines. While Motorcraft is a great oil and has the UOA's to show it, I think there is a better option for me by way of Penz, GTX, MAxlife, or Mobil 1 HM. I will more than likely try the Mobil 1 next OCI since I can rest assure there wouldn't be any oil chemistry compatibility issues with remaining oil form the current fill. I think I will start running 10W30 in the summers.

 

BlazerSS,
You asked for a best option based on what you stated - I gave you one. If you already had oils in mind, why didn't you just say so.I won't waste any more of your or myown time.

 

riddle if you actually read my posts you would have seen that I mentioned the Mobil HM oil as a possiblity. I was just looking for reallife examples of what others are using and have used to stop or keep leaks in check. Im no chemist, but I know that the makeup of certain oils is better for certain engines. I figured people here would know better about the internals of the 4.3 & our seals and gaskets and what migh work best to conditon them based on know problems. thats all.

 

Any oil that is more than 50% synthetic can be called a synthetic oil. The trick is to use an oil that is 100% synthetic. Forget about the myths of leakage... I did. Run your first synthetic oil change as a normal one. Then change your filter every 5000 miles and the oil every 10000 miles. Two filters for every oil change.

 

I still run regular dino oil. Oil changes about every 4000-5000 miles.
Castrol or Valvoline 5w30 and Fram oil filters.
Current truck has 175,000 miles and no engine troubles. I bought it with 27,000 miles on it.
Actually that is what I run in all my vehicles (currently 5) that I maintain.

My Astro van had 286,000 miles on it before Ihydroplaned into a bridge and totaled it. It ran as strong as the day I got it with 60,000 miles on it. And it burned oil during start up, leaky valve guides. I never had any trouble with that engine either.

you can fork out the money for the synthetic, however most gas engines are designed for 150,000 miles before needing a rebuild. Anything over that is due to good maintenance. I plan to hit 300,000 miles before I drop in a V8. [sm=burnout.gif]

edited to add, I too have leaky oil lines and dont really care. they have been leaking for a long time now. Every summer I pressure wash the oil debris off. Maybe one of these days I'll fix them. Maybe not.

 

I use mobil oil and filters never had a problem. ( 98 chevy blazer and 97 chevy tahoe). I use 10 w30 in winter and 10w 40 summer and also add lucas oil stablizer. I have used the same oils in a 91 chevy blazer with over 250 thousands miles on it and it used a very little oil between changes. same with both my trucks now. but my blazer has a new oil leak comming from a oil line the goes to the oil filter in the front under the grill 98 blazer has over 130 thousand on it first oil leak since i owned it going on 5 years.

 

if i can jump in real quick? will a 40 weight help limp and engine with wearing rings along for awhile?

 

You can try it but if the engine is smoking due to badly worn rings there is no cure that comes in a can.