i have a 2005 gmc sierra 1500 and my oil pressure gauge dropped to 0 and is

[EvanS]

knocking and rattling pretty bad? i have a 2005 gmc sierra 1500 with a 5.3 v8 and my oil pressure gauge dropped to 0 and is rattling pretty bad is the oil pump out or something else and is it hard to change and what is the average cost for a mechanic to fix it

[SammyTheBull]

Well I hope you shut it off as soon as the idiot light came on. With all that knocking & rattling it sounds like you kept driving it like a woman would.

You can check the oil pressure wire to make sure it's a solid connection but I doubt that's it. I'm not sure how a 2005 model oil pump could go out either but i guess it's possible. I'll say this is about a $3 or $400 job including picking the car up with their transport.

You could try replacing it yourself. You will need car ramps though & a way to brace them in the garage. I tried putting my car on them & it made long scratch marks that I had to scrub to get off. So unless you have a way to get it up higher, it's an impossible job.

[mackinawbob]

If you have zero oil pressure and the engine is banging around, the damage is already done and it's not worth fixing that engine. It is very uncommon for oil pumps to go out these days. It's more likely the thing spun a bearing. You need to start pricing out replacement engines. You can pull the dipstick and look closely at the oil on it - if there are many small sparkles in it, you're toast.
Off the top of my head, I'd say it will be around $3000 parts and labor to install a good used boneyard engine, and about double that for a remanufactured engine. Sorry for the bad news.