About time I finally figure out what's wrong with my 99' Blazer. It's been sitting for over a year now and I miss it. So a few months before I stopped driving it, I replaced my leaking oil lines (engine to cooler). Few days later as I'm driving down the road, I hear a slight pop and see my oil pressure light turn on. Stopped the car immediately to notice the line for the oil going into the radiator had popped out and sprayed oil all over my engine bay. (Hey at least the bay looks clean and shiny now). Anyways, after getting a new retaining clip, cleaning my car, etc, my Blazer would run perfectly fine for the first 5 to 10 minutes of it being on (quiet engine, good oil pressure, etc). After warming up, oil pressure would drop to what looks like zero and there would be a scratching sound coming from the engine bay when accelerating. I'm thinking (and hoping) it's just the oil pump. Any ideas on what I can do to check? Any help is greatly appreciated. Looking forward to getting my Blazer back on the trails

 

Scratching or screeching?

Could be the V-belt slipping because of all the oil.

 

It's only once the engine is warmed up, after 5 to 10 minutes. It sounds like something scratching inside the engine (metallic sounding). I feel like if it was something like the pistons, rockers, or springs it would happen as soon as I turn on the car. Doesn't sound like a belt at all

 

Forgot to mention, it only has the scratching sound when I hit about 2800 RPM. Whether it's in gear or not, doesn't sound better/worse under load.

 

Looks like it scratched a bearing up good. oil pressure should never be that low, the oil pump evidently would suffer problems as its the first to run out of oil but they typically dont catastrophically break like that (if stopped at low RPM), normally anyways. either way that engines got to come out to be looked over, if it was stopped mid run Immediately at low RPM when it popped off most if not all of the damage will be on the bottom end, so you may get out of it without pulling heads, or even the pistons/valvetrain. make sure you flush the oil passages really really well, flush the cooler, and get a machine shop to fab metal clad hydraulic hose cooler lines. thats what im doing sometime in the next month or so. on your parts list is crank/rod bearings, rear main seal, timing cover and ideally timing set since its the best time to do it, oil pan gasket, some high quality RTV, and a new Oil pump, Recommended stock pressure Melling M55/associated pickup screen and a steel pump shaft with steal retainer. stock part is a steel shaft with plastic retainer and its a really cheap upgrade. make sure the pump pickup fits as tight as possible, really dont want it coming loose, can also weld it to the pump body if you want (and prime the pump with good engine building grease)