Right Oil is Critical. Z
With engine oil used to operate the cam phasers, two aspects of preventative maintenance become even more critical. First, these new Police Interceptor engines MUST have the right weight-viscosity of engine oil. The PCM opens up valves to control the cam phasers based on the correct oil. Too heavy or too light and the cam phaser will over-react or under-react. The VCT phaser not responding correctly to the PCM will cause a DTC: an error in action versus expected cam advance or retard.
Exactly the same condition can occur with dirty oil, specifically oil that has depleted the anti-foam additives. Oil with tiny foam (air) bubbles is more compressible than oil with no foam. So, oil under pressure has to break these tiny bubbles before it can act as a true hydraulic fluid. That will cause a slight delay in the response of the cam phasers to the PCM command.
It won't be much of a delay, but the PCM again monitors actual versus expected and can throw a DTC. Change the oil and the problem goes away. How about using synthetic oil? Nope. It is the anti-foam additive package that gets depleted, not the breakdown of the base stock.
http://www.hendonpub.com/resources/article_archive/results/details?id=4469
