I have an 05 Silverado Z71 and recently my oil pressure guage spiked and holds past 80 when the truck is on. No its not the guage cluster. I just had that fixed and the mechanic told me before he fixed my cluster that the oil pressure sending unit was bad. He said they could fix it but wanted to charge more than $300. I picked one up and the socket to fix it but I am unsure where it is located on the engine. I was told by a friend its on the lower back end of the block but I think he is wrong after searching for hours looking for it and not finding it. Any help would be great, Thanks

 

i have a 08 silverado with a 5.3l and the sending unit was on the top of the engine. i removed the site sheild and used a 27 mm deep socket with a swivel joint and about a 6 inch extention. It was towards the drivers side of the engine. hope this helps. I just learned this and it ended up being the oil filter.

 

On your 05 it should be like mine. Was on the back of the motor, towards the cab, right on top of the block. Is a pain in the a$$ to change but it's definitely there. You can't see it, you have to feel around for it back there