RockinSS04 - this is for you especially. on the issue of flushes, almost all flush servies offered are not true flushes in the sense that they will 'back flush'. most systems are vurtually impossible to backflush anyway. what gets called a flush is almost always simply a fluid exchange. or sometimes a solvent is dumped in, then shortly after is followed by a fluid exchange.

i can only think of 2 things that ever get backflushed
1 - transmission coolers after a transmission failure are back flushed and flow tested before the new trans. is hooked up.
2 - s-10s, sonomas, jimmys, blazers with a 4.3 with a blocked heater core, get a garden hose hooked up to back flush.

 

Ok, if your manual reccomends 5w30 in cold weather and 10 w 30 in warm, get some synth 5w30. Next, put half a can of "seafoam" in the oil. Run it for a good 1000 miles. make sure to give it a good run, high temp, high rpm, cold temp, high RPM, (high tempmeaning as high as the temp will get without going nuts like unplugging the radiator fan or something) Long runs, short jaunts, the whole kit n caboodle. Then, change it and the filter at 1000k, and stick with synth , just whatever the manual reccoments for ambient temps

Seafoam actually says to put it in the tank as well, which won't hurt at all, but personally I would put the remaining half in the vacuum system so it gets in the intake and does its job on the injectors and all.

Next oil change, give it 3k...

Then go to the synth you want to stick with, a good quality oil filter, and if you have a oil life system live by that, or you could probably give it 6k between changes. The MAJOR factor between oil changes is run time... if by the time the car is shut off, it's not fully up to temp ( less than 5 minutes of driving) it's going to be a lot worse on the oil. This means the oild can't get up to boiling, and boil out water vapor, which will sit with the oil, causing it to mix with oil contaminates and create harmful acids and the like. If youraverage (1/3 of trips or more)is 5 minutes or less, stick to 3k oil changes.

 

well upon popular demand i wont be doing a engine flush anytime soon or never!thanks on all the great info.good to know why that would be a bad idea