well do to my finances ive been pretty careless with my oil change should have been changed 5k miles ago but i have the money now and i was thinking about using valvoline high milage, ive grown up around a high performance shop and have been brought up to strickly use valvoline products with a little marvel mistery oil i was just curious what everyone else would recomend its the stock 4.3 with 99,6XX miles on it, also isnt there a magnet that i can put on the oil filter to like help clean it what type of magnet do i use?

 

That oil will be fine. These engines do just fine with any name brand dino oil going 3,000-5,000 miles between changes. I think the MMO would only need using once in a blue moon, though. I'm ambivalent about the filter magnet, but you can get a magnetic drain plug from your local Chevy dealer.

 

I want to switch to high mileage synthetic just because I'm scared my engine's going to look like this:


or



(pics are from my LR forum...guy bought a used Discovery II and had low-ish oil pressure so he dropped the pan and found the 2nd pic, which led him to pull the valve covers for check, and found the 1st pic [:'(])

 

Ah, yes, sludge and varnish, two of my favorites! HM oil wouldn't prevent that, I'm afraid. I feel that sludge is due to a combimation of over-extended oil changes and faulty engine design (*cough-late 90's Toyotas-cough*). In engines with >100k on them a HM wouldn't hurt to help keep engine seals soft, though.

 

So regular oil changes are the best way to keep that stuff out of our Blazers? What about doing an ATF engine flush?

 

That and keeping the engine temperature in the right zone. How many miles on the tranny?

 

102k on the tranny and engine, and I've always done oil changes at 4-5k miles, did a tranny flush/filter/fluid at 95k, fluid is still nice and red. I've just read about filling the crankcase with ATF, running for a few minutes, then draining and replacing with synthetic oil to really kill the sludge.

 

When you say you 'flushed' the tranny, do you mean that you did a drain/fill or a machine flush? Either way, I like to do a pan drop and drain somewhere between every 20,000-30,000 miles. Dexron VI, the new GM tranny fluid standard, is a synthetic so that's what I would use.

 

Machine flush at my mechanic. Cost me entirely too much $

How new is Dextron VI? I the power flush was done maybe a year and a half ago...would that still have been Dextron III or IV they used? I'm just gauging if I should do a drain/fill to get some VI in there.

 

About 6 weeks ago I bought a quart of D-VI for ~$6. D-VI was introduced in April, 2005 and all manufacturing licenses for D-III (there was no D-IV or V) expired at the end of 2006. If you get another drain & fill, ask them if they are using D-VI since the shop may still be using up old stock of D-III. Don't worry about mixing them together since D-VI was designed to be fully backwards compatible.
I wouldn't do that. Instead, I would use Auto-Rx fro a nice, gentle, but thorough engine internal cleaning. Highly respected product.