GenVibe - Community for Pontiac Vibe Enthusiasts

Got a 2006 Vibe with automatic transmission and 164k miles for $3800. New tires, exhaust, ice cold A/C, no rust, Very nice car except the engine seized up on highway 30 minutes into a trip to an inspection station last Friday. First, oil light started to flicker. Few minutes later a rattling noise at which point I quickly pulled over to the nearest gas station (5 minutes after I started hearing the noise). Oil level was almost full. Added pint of oil, started the car, surprisingly quiet, got back on the road and 1/4 of a mile later the rattling came back, instantly intensified and the car stalled right away. Local mechanic will get me prices for rebuilt engine with 3 year warranty and used 75k miles with one year warranty. Sounds like used engine might be a safer bet but I read that rebuilt engine could be as good as OEM. Any thoughts? Also why would the engine run like a champ during the test drive and a 15 minute trip home. Was the problem possibly masked by the seller's mechanic? Did the oil pump fail? $4k is a lot to swallow...not sure what to do honestly.
Update on the price- $5400 installed used engine 71k miles

Welcome to genvibe!
Sorry to hear about the problem with your new-to-you Vibe.
Sounds like your oil pump pickup may have gotten clogged?
There have been a couple of other posts about this issue recently.
$5400 seems a bit high for an engine replacement.
I would probably search for another Vibe for $5400 or less.
There are still nice ones out there to be had.
Keep us updated on the your decisions.

My coworker hooked me up with a mechanic who will rebuild (hopefully remanufacture) the engine for $2500. I can only trust my friend's recommendation and the mechanics expertise.
About the seized engine...yes I heard rattling and knocking that lead it to stall. The engine temperature never spiked though and oil level was ok. So was it really lack of lubrication? I doubt the oil pump failed. Thinking something got loose ? The current mechanic said he saw metal particles in the engine oil.