OIL pressure dropped on idle after oil change?
#1
OIL pressure dropped on idle after oil change?
So as the title states, i just changed my oil to mobil 1 full synthetic 10w30 ( i live in FL) with a k&n oil filter and since ive owned the car the oil pressure has never dropped below 40, for some reason as i was driving home and i parked i looked at it dropped to about 35ish? Oil pressure rises as i accelerate just sort of worried since ive never seen the oil pressure this low. Any insight on this?
Last edited by adamantium; 04-18-2012 at 05:45 PM.
#2
What oil were you running prior to this oil change? Synthetic oils will have less resistance travelling through the engine, which would lead me to believe that it could cause lower oil pressure. Interesting question.
#3
Not sure, ive owned the car for maybe 3 weeks or so and the previous owner told me he used mobil 1 synthetic, but i forgot what weight he used. For some reason i keep hearing a tick that goes away and comes back aswell. It goes away as soon as i give it gas though. Oil level is at the top aswell.
#4
Oil viscosity will definitely change the idle oil pressure. Also, keep in mind that oil temperature also changes oil viscosity. The hotter the oil, the lower your idle pressure will be. 35 psi idle with fully hot oil is good for an LS engine. I wouldn't worry about it since you really don't know what was in the engine before you changed it.
#5
Is the car modified at all? Ticking could just be an exhaust leak. My 317 heads have a couple of broken exhaust manifold bolts and it ticks until I give it gas. I'm putting new heads on in a couple week so I am looking forward to a tick free engine. Lol.
#6
Oil viscosity will definitely change the idle oil pressure. Also, keep in mind that oil temperature also changes oil viscosity. The hotter the oil, the lower your idle pressure will be. 35 psi idle with fully hot oil is good for an LS engine. I wouldn't worry about it since you really don't know what was in the engine before you changed it.
Maybe im just going crazy. Might be an exhaust leak but i dont see any reason for it. Cars driven great till ive done the oil change and tune up. All it has is an SLP lid and a flowmaster turd in place of the OEM muffler.
#7
Seems like it might be an exhaust leak since i just remembered i took out the pass side AIR hose to the header when i did the plugs and msd wire swap, sounds like its mainly coming from the pass side, which is also the only AIR hose i remove and reinstalled (lets hope its that).
As for the oil pressure the more i drive the car the more the oil pressure slowly drops on idle. When it drops below 40 the needle is "jumpy". temp needle is right in the center ive seen it a bit higher than that and oil pressure was always just above 40 with the old thin *** black oil it had. Im stumped.
I remember reading the 02 temp gauges are "dummys" unless the cars really really hot and its not showing on the temp gauge that might be the ONLY explanation i can think as to why my oil pressure is dropping below 40.
As for the oil pressure the more i drive the car the more the oil pressure slowly drops on idle. When it drops below 40 the needle is "jumpy". temp needle is right in the center ive seen it a bit higher than that and oil pressure was always just above 40 with the old thin *** black oil it had. Im stumped.
I remember reading the 02 temp gauges are "dummys" unless the cars really really hot and its not showing on the temp gauge that might be the ONLY explanation i can think as to why my oil pressure is dropping below 40.
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#9
Mobile 1 does that in my car, and for whatever reason, only mobil 1. The pressure gauge is alway just a TINY bit below the 40 mark. Everything else Ive used (that I can remember) shows 40.
I think that stuff is just a little bit thinner than other brands.
I think that stuff is just a little bit thinner than other brands.
#10
Also the first time i started it after the oil change i measured the oil cold and the oil was a bit higher than the mark so ii took out maybe 1/4 of a quart of oil started it up and thats when i heard the tick and when i measured the oil again it was where the "add oil" line was at, so i re added oil and that ticking sound hasn't left.
#11
#12
That's a lot of shotgunning. Any idea what the actual pressure is? You can access the oil galley on the driver side of the block to do a mech pressure test. Need to 16mm x 1.5mm male adapter to screw into the block. Also, there is a screen under the pressure sensor that I would remove and check for debris/clogged. You could start there before you bust out the gauge.
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