quote:Originally posted by veryfast italain:
My oil pressure goes up and down. It's always between the middle (top) and the left (low), but not extreme left hash marks.
Oil pressure seems to go down when I'm going up a long mountain or when accelerating hard. Oil pressure seems to go back up when going down hill or on a long flat straight.
At times, in hot weather (over 105 degrees outside and closer to 125 degrees on the pavement surface) the oil pressure seems to jump around a little, even at steady speed (80 mph, 3200 rpm), flat, level roads. Oil pressure goes from middle location (35 psig) to the lower lever (17.5 or 20 psig).
What the heck is causing this? If I put a new PCV valve in will that steady out the oil pressure? Is it a good idea to put two PCV valves in the line?
Should I be concerned? I'm just guessing at low rpm, the vacuum is low and the oil pressure is higher, and at higher rpm, there's more vacuum and less oil pressure. Is there any relationship between vacuum and oil pressure? What's too low or too high for oil pressure with a stock 351-C? Thanks.
Ron, in the last 4 plus years of ownership I too have experienced the "bouncing needle" oil pressure gauge that makes one nervous. I tried two different oil weights, 10/40 and 20/50, various oil filters and even went as far as replacing all rod and main bearings.........all without a change.
Then last week I did my oil change and installed my Pure Power filter that I got "a deal" on while at SEMA. The oil pressure has been steady since the install, and I mean rock solid and consistant between the last hash mark and the 70 point. You can install these either with a bypass valve, or a block off plate so all oil must be filtered, I chose the latter. Note that the Pure Power filter flows 90% more per area than a conventional filter.
Could it be that the oil pressure flucuations are caused when the typical paper filter can not allow enough oil to flow through (oil pressure then drops) until the pressure inside the filter generated by the oil backing up causes the built in bypass valve to open (the pressure then goes up), this process repeats itself over and over giving us the bouncing needle syndrome.
Keep in mind this is just theory, but the filter itself is the only parameter that changed. Is anyone else running this filter that could provide feedback?
Ron