hoping you can help me out.
 

I have a friend that has a caddy CTS V with the ls6 in it. He is is loosing oil pressure. What he said is, if he lets the car idle it get 30-40 psi once it is warmed up he gets 5psi and can hear the engine knocking. He took it back and they said they replaced the oil pump but it's not on the paperwork. I still told him it's the pump and if it's not on the paperwork they didn't do it.

What do you guys think?

Did the oil pump fix the problem?

Nope it is still doing the same thing. Which makes me believe they did not replace the oil pump.

What model year and where is he located?

I'm confused. If the car is running 5 psi at idle, he should not be driving it. If the shop made a diagnosis of an oil pump, and it did not fix the problem, that's on their dime. What do they think the problem is, and why did he take the car home if it's not fixed?

It is an 04 caddy cts V Ls6 I think it's a 6spd not sure. He is located in New Jersey. He bought it from a dealer. When he bought it, it had no warranty as is. He said they guy started it up and it was fine, he was driving it home and noticed that it droped to 5 psi. He got it home and called the dealer they said oh well as is. They would look at it but it would cost him. So he brought it back, the person he spoke to said that they replaced the oil pump but it was not on the invioce. He got it back and it's doing the same thing. The car is fine at first it's when it gets hot or warmed up it's not right away. If he leaves it in the driveway and starts it he gets 30-40 psi. If he leaves it there for about 15-20 mins the oil pressure drops to 5psi. Told him to bring it back but he doesn't trust them to work on it.

Right, with good reason. If they told him they replaced an oil pump, and it did not fix the problem, he should not have to pay for that. Misdiagnoisis is their problem, not the customers.

I doubt they replaced the oil pump. It is like 8 hours labor. Have him take it to a Corvette specialist and have it plugged into a scanner.

LOL I wouldn't either, told him to bring it back and tell them the same thing is happening. He doesn't weant to take it there again but If he takes it some where else they will charge him again.

If it happened and was reported to the selling dealer the day he bought it, he should be able to return the car and get his money back whether the dealer says as is or not,he has rights also under most states lemon laws!