Yeah unfortunately it is, it depends on the severity of it. I found a few videos of engines that make little or no noise at idle but as soon as they're reved it comes out. but like I said try pulling the plug wire associated with the front two cylinders, one at a time of course. Even put the steathescope on the oil pan and see if its louder. You could only hear mine outside the car at 2500rpm when driving and above maybe 1200 when parked but on that part of the oil pan you could faintly hear it at idle. If you want to you can drop the oil pan and literlly grap each rod cap and see if there is play in it. Unfortunately that noise sounds exactly like what I have and just like what rod knock is. I guess we'll have to see how this comes out. I hope we both just have oddly defective water pumps . Remember that in an engine the crank can carry sound from one side to another. When I first heard my noise I thought it was an idler pulley or something on that end too cause it was so loud but from under it it sounds like the furthest cylinder from it! Check it out, lemme know what you come up with.

It really all depends on the level of damage done. A new rod bearing isn't all that much, I think you could get change for a $20 for it. You would have to pull the oil pan (not very hard) and check which one you can literally shake. Then pull the two rod cap bolts and take a look at the bearings. They'll probably be really messed up looking. Replace them and check the clearances with plastigauge and reference that to what the book says is allowable. If its within tolerances you could probably be fine like nothing ever happened. If the clearances are way off then I'm sorry but there really isn't anything besides pulling the engine, yanking the crank and rods, and re machining all of them to be within tolerances then reassembling them. Most places I've read up on this suggest simply buying a new engine if they're out of specs. This is a really nasty problem...

I just talked to the guy that I got the car from and he said that when the knock started they checked the oil and there was no metal in it. Does that make a differance in diagnosis?

Yes and no. There should be metal in the oil but most of it would have been caught up in the oil filter. At least most of the openly visable ones. If you're still using the oil filter that was on when the noise started then you can cut it open and surely see flakes of metal. I sent an oil sample of mine off to the lab to be tested as to the level of damage done. You may still be able to cut the oil filter open and see metal flakes because if it is what is happening it should stilll be beating that bearing up pretty bad. But if you do the other tests I said above and they all come out you can probably be 99% sure thats what it is.

Another problem for me. I can't do work like that where I live. I'm going to have to bring this to a mechanic or tow it to where I can do it and that'* about two hours from here. I need an alternator as well. I could put a new one on but I don't want to spend the cash if It'* just going to take another $3k to get the car up.

OK I think I'm just going sell it. More than I want to deal with right now. What'* a good price?

hell don't ask me I paid nearly 2.5x the worth of mine haha. Honestly though if you're going to sell it a $24 rod bearing from gmpartsdirect.com and 2hrs of your time can up the asking price significantly to anyone who can regognize that sound. Honestly with knowing that sound (and if that truely is the problem) I wouldn't pay $100 for it because if not fixed it WILL throw a rod soon. That bearing is going to become so small that the crank will actually beat the rod bolts to pieces and the rod is gonna come right out the bottom end on the next stroke. Its really not too difficult to do. All you need is basic hand tools and a saturday. If the body and everything else is in good shape I'd replace that rod bearing and go get some CDC engine cleaner. Its a two step cleaner that has two bottles. One is a heavy engine degreaser and the other makes all the plastic look really shiny. $30 and 2.5hours can add another $800+++ to the asking price I'm sure because the engine will sound nice and look nearly brand new. Its amazing what this cleaner will do. I'd think about that before posting the "For Sale" sign.

I would love to get into the car to do that but I would be looking at about $100 for an alternator, the parts and the the money to rent a garage that I could do the work in. If i do it where I live I'll get evicted. I'm a disabled Vet and not exactlly the richest person so this all starts to add up. If I had the place to do it, I would be fine with it as the parts aren't that spendy and I can turn a wrench. I just don't want to get in over my head money wise or invest alot of time and money into something I can fix in the very near future. If I find that I do need a rebuild, or new motor as you said it will be 10x harder to sell the car. I really want to fix this car but I think my hands are tied right now.

Hold your horsies. I have a co-worker here who had a water pump failure on a 4.3 Vortec in a Blazer that sounded EXACTLY like that. They thought it was a rod bearing, too.

We need a little better diagnosis.

Well I gave you three ways to diagnose it. Pull the spark plug, it should rattle twice as much.. Listen on the bottom the oil pan, it should be louder. Or even pull the pan and shake the rod.