I have an '05 Suburban LTZ 4WD with 243k miles and after the oil pump died on my wife's drive to Charlotte we're told we may have spun the camshaft bearings because she had to drive so long with the low oil pressure warning blaring.

After that drive, the oil pump was replaced for $1200 and a month prior to this I put $900 into some top end work (head gasket, exhaust manifold bolts, etc...) so I've dropped about $2k into this engine and it's still not really drivable. Current problem is that while driving the oil pressure comes up to maybe halfway to where it should be and as soon as the RPMs come down to idle for more than 5-10 seconds the oil pressure drops to zero and the warning comes on again. The mechanic had the passenger side valve cover off while at idle and sure enough, zero oil was coming out when it should have been splashing everywhere.

I'm told my options are:

1) Drop the oil pan and related in the way parts to check out the previous mechanic's oil pump installation job and see if he maybe pinched an O ring or something and fix whatever may be wrong.

2) Tear down the engine to replace the camshaft and bearings.

3) Get a remanufactured engine installed.

What are your thoughts on whether it's worth getting a replacement engine for this old truck? Is it worth the nearly $5k expense by getting a GM certified 5.3 for $4k? Do I risk getting a bum reman engine from some online place for a couple grand less than the GM certified engine? Do I cut my losses and sell her as is for whatever I can get?

Let me know what you think - I'd appreciate the input.

Thanks

Scott