HELP! Service Code P0521 Dealer Says Replace Engine
 

I have a 2013 Silverado 1500 LTZ 5.3L V8 4x4 crew cab with 93k miles. Runs fine. Service Engine warning light is on. Service Code P0521.
My son took vehicle in to Dealer's service center where they performed manual oil pressure test upper and lower: reported 10 pound difference in oil pressure from top to bottom.
Dealer Service Recommended ENGINE REPLACEMENT!! And, charged $260 for oil pressure test.
Seems like an extreme resolution recommendation, and expensive diagnostic fee. Do these things make any sense - replace engine recommendation and $260 fee for diagnosis???
Vehicle has been regularly/properly maintained - all regular oil changes have been performed at dealership where vehicle was purchased (same dealership recommending engine replacement).
I have not tt dealer service center personally (as my son took vehicle in for service). I would expect if remedy is engine replacement that cause is major defect that Chevrolet would cover.
Thoughts or Advice??

You just need a new oil pressure sensor. It's a bitch to get too, but cheaper than the new motor the dealer wants.

I have the same problem with my '07 Tahoe
 

The Oil Pressure switch in question is under the intake manifold at the rear of the engine-it's one of those jobs that costs $40 in parts and many times that in labor. If it's not something you think you can do on your own, or you don't have the tools for, seek out an independent shop with a good reputation, they probably have done several, if not dozens, and you should have a cost estimate before work begins. If you decide to do it yourself (not a good first job for a beginner) and you have the fuel saving engine, do not remove the valley pan beneath the intake manifold, the connections for the disabling of the lifters is incorporated into that cover. Also, with the fuel saving engine, there is a screen fitted to the bottom of the switch, make sure the old one is out, and the new one is in (there are two p/n's for my '07). Some people say that the switch can be accessed without removing the manifold, but I couldn't on my '07. Oh, and I'd find a new dealership to do business with...

This video should help you out:

Dealer says it is not sensor as manual pressure test had upper pressure low. I spoke with service advisor (SA) who said usually lower pressure is low, so he would revert to technician. SA calls back - tech wasn’t available, but foreman was and suggested probably just needs an oil change and new filter and more frequent (every 3k) oil changes going forward. Odd that this is remedy when complete engine change was first recommended. All oil changes have been performed at this dealership.

Why not do oil changes yourself?. Set of ramps, oil filter wrench, a creeper, and the proper oil pan drain plug removal socket. Also need a drain pan and waste oil storage for oil recycling. Punch a hole in the bottom of the oil filter to drain the oil out. Take the used oil and filter to any parts store. They have to take if for free.3000 miles is too soon with Dexos 2 full-synthetic motor oil. 5000 miles is better.

What were the actual oil pressure readings? These AFM engines have 2 oil pressure relief valves - 1 in the oil pump and 1 in the oil pan, just above the filter - both of which are known for having problems sticking open.

However the oil pressure sensors are also known for having problems, so the actual readings of the pressure test will determine what the likely problem is.

Man, after reading all these posts about AMF engines, I'm a gonna keep my "Betsy" until she up and dies. Then I'll put her back into shape again.Quality control is DOWN the drain, and how much fuel do you save if you have to dump a bunch of money down the drain repairing these vehicles? And let me make it clear: I am not just speaking of GM/Chevrolet vehicles at all. How do you beat an 23 year old original fuel pump, original injectors and no O2 sensors ever replaced? You cannot with these new vehicles.

You save plenty of fuel because you’re not driving it. :D

I get what you mean, but this is just as much on federal fuel economy standards as it is the manufacturers. Automakers are being forced to implement systems and components that haven’t been adequately tested to determine longevity, or in some cases, practical application, for the sake of meeting deadlines.

Just like when DEF and exhaust after treatment systems on diesels were introduced - every manufacturer, whether auto or heavy truck, had problems with those systems and the problems depended on who made the components and who assembled it. Then the first few years passed, the initial problems were addressed and the systems became more dependable (not that they’re perfect now by any means).

Unfortunately the oil pressure issues aren’t limited to the AFM engines because the oil pump is the same whether it’s AFM or not.

That said, low oil pressure for these trucks is not a death sentence. I recently had a customer with a 2009 2500 HD 6.0 and IIRC about 125,000 miles (non-AFM I think the RPO was L83) come in because the oil pressure gauge was reading zero and the warning chime was going off. He’s a regular customer that’s been consistent with maintenance. Other than a light ticking from the valves, there was NO noise.

I pulled the sensor to check with a mechanical gauge - 0 PSI. I pulled the filter to check pressure - 0 PSI. I found the pressure relief valve for the pump was stuck open, so it basically pumping oil straight back into the pan. A new oil pump fixed the problem.

Mind you, the oil flows from the pump, to the cooler, then to the filter before it flows to ANY bearings, so how it is that engine didn’t have a rod knock, I can’t explain. I won’t be surprised if it develops one in the future (or other oil related problem), but for now it’s running as of nothing happened.