My car is the shop because of cam timing issue (5.0 NA). This is the 4th time. They replaced the timing chain and all ancillaries, actuators, as well as the sensors. The problem still occurs. They contacted Jaguar technical who asked for hot and cold oil pressures. At speed, the oil pressure is good, but is low at idle. The service manager thinks it is the oil pump, but is waiting to hear from Jag. The car has 96,000 miles and even though I bought it used, it has been maintained by the dealer, (I have changed the oil every 7500 miles).
He didn’t give me the numbers. I went with oil pump because of what the service manager said, Like you say it could be the bypass (oil pressure relief valve), or worst (or best, if they give me a news engine) case scenario worn bearings.but I doubt it is bearings because the car is a CPO and I have the service records. Oil changes were done at a shorter interval than the book says.
Here is the final outcome. The car was timed out of the CPO warranty (it expired in August). It was still below the mileage limit. The car had been service exclusively at a Jaguar dealer, and been maintained better than the book calls for.
The dealer contact Jag, and Jag is giving me a new (rebuilt?) engine. The dealer is charging me $4200 to install it. (I didn’t buy the car at this dealer. The dealer I bought it from went out of business and this dealer took over the franchise.
The 4200 includes new spark plugs (the new engine does not come with them, and I don’t want 97,000 mile plugs in the car. The same for the serpentine belt. It includes the oil and coolant.
The rest of the car, body, etc., is good.
BTW the oil pressure at idle was 3 psi.
When the problem started in July, they never measured oil pressure. I believe that if they had they might have found it low. The other possibility is a catastrophic failure of the oil system.