2000 Astro main engine bearing failure

[JTemple]

Readers Digest Version: Bought this 2000 AWD Astro Van used 5 months ago, from a neighbor/friend who has been a GM mechanic for 25 years. Well maintained, 45,000 miles. Mint condition - beautiful van - ran perfect. But in the past 5 months I've had to replace the starter, alternator, serpentine fan belt, and now have horrible misfiring situation. My mechanic has replaced the cap and rotor, two burned out fuel injectors (#3 and #5), all the plugs, and now there's a bad engine knock. He changed the oil and found gas and metal filings in the oil. He says my main engine bearing is going. GM says it's never heard of the problem, but a simple search on the web proves otherwise. Obviously, GM wants me to have a dealer diagnose the problem - car is not under any warranty. Question: Should I bother with GM? How expensive is it to change the main engine bearing? Could the knocking be anything else? Compression and oil pressure are fine. Any info would be gratefully appreciated.

[shroom]

hi i got a 90 astro, you probally have a vortec engine in it, it sounds like it, me throttle body injectors, anyhow the knocking noise, does your oil pressure drop when this happens, if not ok, one way i isolated my problem was to pull each plug wire one at a time and start it and listen i kept going until the noise wasnt there, funny thought cylinder 1 and 2 made the noise which told me the mail bearing was failing, you already have shavings, which would indicate a bearing problem to me, if your not familar with what to look for in a bad bearing i would suggest finding a friend, cuz,,,,,,, you have to drop the oil pan to look at the bearing, it has two cap bolts,5/8's size i believe, and you probally will have to take off the inspection plate to the flywheel, take off the starter, now those bearings come in different sizes , flanged unflanged, aluminum,tri metal, so having a mechanic do it will cost you alot of labor, oh and they suggest you replace the oil pan seal too. i am getting ready to replace my oil pump, hopefully i hvent ruined a connecting rod bearing. good luck, just call up a mechanic and ask them how much to replace a main, get ready, could be 4-500.00 dolllars. as for the gm dealer, huh..... as for your serpentine belt, if you start going through those, check your tension belt adjuster, you shouldnt be able to pull it up with your hands.
well thats all i can help you with

[acmegoat]

If there's bearing material in the pan and/or oil filter and your model has a remote oil cooler don't consider the repair complete until you've replaced the oil cooler/radiator. I just replaced the long block in my '94 AWD and the rebuilder warned me that the oil cooler can NOT be flushed. He had an old cooler under his bench that they'd disected. The passages are so small that it retains old metal bits and will toast the new motor.
Just thought I should share.