High Mileage Oil?

[bkelley]

Getting ready to give my '85 Blazer a tune up. Oil change, new plugs, filters, valve cover gaskets, et cetera. She's sitting at just about 117k miles (all original) and I've only ran conventional 10W-40 oil, never tried any synthetic or high mileage stuff before. Pretty sure it's not burning or anything, but I can't exactly tell because it does have a slight leak (hence the new valve cover gaskets). I usually have to put 1/2 a quart or so in every few weeks to accommodate for the leak. Anyways, I was just wondering what you guys think of the high mileage/synthetic oils. I've heard mixed reviews. Some people say they noticed a drastic decrease in oil burn and others say it doesn't do a damn thing.

I was also thinking about trying out Auto-Rx (http://www.auto-rx.com/index.html) instead. It's $26 a bottle (shipped) but it's supposed to work great and you only need to do one application. Two applications are recommended for high mileage/abused vehicles. Problem is, it takes 3oz per quart of oil and the bottle is only 12oz. So, I would need a total of three bottles ($65) to complete the two application cleanse. I would still have to buy two bottles just for the basic application ($45).

So, what do you guys think I should do?

[VTredneckgames]

Dont waste your time or money on that extra stuff.

Put whatever oil in you want. It will not make that much difference. If you would like to run a synthetic, then put one in. They are not that much more expensive anymore and they can be run longer between changes. I just recently swapped to synthetic in my 88 1500 with the 4.3. It idles alittle smoother, but other then that I cant tell a difference. Leaks just the same amount as it did.

[Sjorge450R]

i have also been told that synthetics can clean your engine and when you do this on a older car, it cleans out some gunk that may be actually stopping an oil leak. therefore, putting synthetic could actually give you a worse oil leak problem.

[bkelley]

Any other opinions?

[ZeroLogic]

I call it all bs. My father's old truck had almost 300,000 miles on it. Never used that stuff before. The frame gave out and the motor still ran strong. I run 10w-40 10w-30 depending on the temp outside. Never had a problem and never burns any oil.

[honda300EXtreme]

it is possible to see new oil leaks appear or existing ones get worse if you switch to synthetic.

i personally use penzoil high mileage. do i think the high mileage name makes any difference? not really. but its only an extra two bucks so why not.

stay away from additives. if they were as good as they claim oil companys would be adding them to there oils already. alot of additives do more damage than good yes even the 20 dollar a bottle zmax lol but we could start a whole nother discussion on that.