i own a 2002 blazer and have owned it since it was new. it has always used Mobil 1 and changed regularly. about six months ago i heard a terrible tapping when i started the engine. After about 5 mins it went away. i changed the oil which was only 1500 miles old and the noise did not appear again for 1000 miles and it started doing it again. it was confirmed that it was a stuck lifter and that those engines had a habit of lower intake manifold gaskets leaking antifreeze into the crankcase. After feeling pretty comfortable that this was indeed the problem i took the manifold off and found the engine to have a fair amount of sludge in it. I am not a pro mechanic but it looked pretty bad to me. i could take an lift it up with a screwdriver in places. Anyway, i cleaned things up as well as i could and put her all back together. Here is where i actually ask a question. I am not really a fan of additives ect but im nervous about the sludge that is in the engine now. I filled the crankcase with walmart 10w30 and plan to run it 1000 miles then change it back to the synthetic. The truck has been back together now for 4 days and seems to run great. One thing i noticed is that the new oil i put in still looks brand new on the dipstick. i would think it would get dirty fast due to all the [censored] in the engine. this leads me to believe that it is not cleaning up anything. I have run rotella in some of my other gas trucks for a long time and don't seem to have an issue with it so i was thinking about running that for a while due to the higher detergent concentration but im not sure. If anyone has had this issue before as it is different than some generic sludge problem due to laziness please advice or share your success story. I believe the engine is in good shape but i would just like to get the sludge out of it. It has 170000 miles so it would be considered high mileage. I have heard several methods of trying such as tranny fluid, MMO,SeaFoam,Rotella,Just run synthetics as they will clean it out slowly. Also im not sure if this is different due to the fact that the sludge is caused by antifreeze in the oil and not neglect.
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