I've a 94 Astro with that 4.3 at 220k and it's seeping at that rear main and valve covers. I've cinched down the VC's and am living w/the main seal. My main prob is a burnt valve on #5 ex. The rest of the cyls are 125lbs straight across and it doesn't burn a drop. I'd still be driving it except for that dead hole. Even on 5 cyls I can still tow a loaded trailer without too much grunting!
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