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Originally Posted by JFP in PA
How does the current design or the pump’s pressure regulator supposedly respond to changes in temperature? Just wondering……………..
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i'm not 100% positive, but my educated guess is that as the spring heats up, it changes length, moving the piston into or out of the oil pump to alter flow. i have verified the oil pressure goes sky high at cold start & that this is normal. this is detailed in the owners manual. i think this is a pretty old design for porsche & is on a lot of their older cars.
a lot of the cars that tick experience mildly low oil pressure at idle, generally around 1 bar rather than the 1.5 spec'd in the manual. i'm thinking that over time, the spring's ability to properly actuate the piston diminishes, resulting in slightly low oil pressure at idle. i think this is the reason the ticking goes away with event a TINY application of throttle (i.e. 1200 RPM).
the spring and piston (25 & 26) in this photo are the parts at work. sometimes, the piston can get stuck & cause issues as well.