Drop in oil pressure
08-22-2012, 11:07 AM
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Drop in oil pressure
My idle pressure has went from 15 psi to less than 10. My high rpm pressure does not go over 90 now where it used to hit 120. I tried searching and only found posts that the presume was totally zero. The drop in pressure has been in the last two days. Any suggestions?
08-22-2012, 11:14 AM
#2
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How high is your oil level?
08-22-2012, 11:18 AM
#3
Moved to the correct subforum and you should reference this post in the Top 100 FAQ OP:
https://my350z.com/forum/2690886-post22.html
Q What is a normal oil pressure?? My oil pressure is going crazy high!
A: The key here is that it does not get too low. When you first start the car, i.e. a cold start, your oil pressure may be as high as 100 psi. When your oil warms up, the viscosity drops, and the pressure will be lower. Please see the owner's manual for normal oil pressure range.
Rules of thumb:
At COLD idle/on cold starts, your oil pressure should be about 40-90 psi.
At normal operating temperature idle, your oil pressure should be about 15-30 psi. (If your idle has been raised it may read a little higher. If you are running without your A/C it will read a little lower. These are just ballpark numbers.)
Don't redline the car or drive hard until the oil warms up and the oil pressure at idle drops. At high RPM the pressure may go off the scale. That is OK as long as the car is warmed up.
Note: it takes longer for your oil to warm up than it takes for your coolant to warm up. Don't go by the temperature gauge on the dash board to determine if the car is 100% warmed up...
If you think you're having oil pressure issues, first get an oil change and see if the pressure goes to the normal range. Using different viscosities of oil will result in slightly different pressure behavior. The recommended oil for your car is 5W-30 (usual choice, good for winter), 10W-30 (also typical choice, good for summer), and 10W-40 (usually used only for extremely high temperature conditions). If you go too long without an oil change, your oil can start to exhibit viscous breakdown, and your oil pressure may drop below normal.
Oil pressure and oil level are NOT THE SAME. Low pressure does not necessarily mean low oil. But low pressure DOES mean you should probably change the oil.
If the oil change does not solve your pressure problems, there could be a problem with your oil pressure sensor. Damage to this sensor CAN occur if a mechanic is careless underneath your car.
https://my350z.com/forum/2690886-post22.html
Q What is a normal oil pressure?? My oil pressure is going crazy high!
A: The key here is that it does not get too low. When you first start the car, i.e. a cold start, your oil pressure may be as high as 100 psi. When your oil warms up, the viscosity drops, and the pressure will be lower. Please see the owner's manual for normal oil pressure range.
Rules of thumb:
At COLD idle/on cold starts, your oil pressure should be about 40-90 psi.
At normal operating temperature idle, your oil pressure should be about 15-30 psi. (If your idle has been raised it may read a little higher. If you are running without your A/C it will read a little lower. These are just ballpark numbers.)
Don't redline the car or drive hard until the oil warms up and the oil pressure at idle drops. At high RPM the pressure may go off the scale. That is OK as long as the car is warmed up.
Note: it takes longer for your oil to warm up than it takes for your coolant to warm up. Don't go by the temperature gauge on the dash board to determine if the car is 100% warmed up...
If you think you're having oil pressure issues, first get an oil change and see if the pressure goes to the normal range. Using different viscosities of oil will result in slightly different pressure behavior. The recommended oil for your car is 5W-30 (usual choice, good for winter), 10W-30 (also typical choice, good for summer), and 10W-40 (usually used only for extremely high temperature conditions). If you go too long without an oil change, your oil can start to exhibit viscous breakdown, and your oil pressure may drop below normal.
Oil pressure and oil level are NOT THE SAME. Low pressure does not necessarily mean low oil. But low pressure DOES mean you should probably change the oil.
If the oil change does not solve your pressure problems, there could be a problem with your oil pressure sensor. Damage to this sensor CAN occur if a mechanic is careless underneath your car.
08-22-2012, 01:56 PM
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I did reference the top 100. That's not what is happening with my car. Normally, about 4 days ago it was idling at startup between 30-60, and then dropping to 15 when warm. Now it's less than 10 and doesn't go above 90 on a warm engine. I checked and changed my oil as I do every 3 mos. the level was normal and I'm using the 5w30 dyno. I understand there are normally different ranges depending on the temp of the engine and obviously rpm. The change that has suddenly occurred is what is worrying me.
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08-22-2012, 04:15 PM
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Na I didn't over rev it. The only thing I did do differently was add a bottle of gumout to the gas about a week and a half ago. Could that have caused a change in pressure?
08-23-2012, 05:12 AM
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weird, my z seemed to be loosing pressure last night... its an 08 as well but only at idle it drops below 100kpa my idle seems to drop too it will drop from 700 to 550~ almost. you think i need to do an idle relearn? at higher rpm the pressure is over spec
08-24-2012, 11:54 AM
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Well the dealer replaced the sensor and nothing changed. Their "head technician" doesn't know what is causing the drop. He tried saying the oil was old but they just changed it 2 days ago.
08-25-2012, 09:57 AM
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I looked in the FSM what the normal oil pressure values are supposed to be and idle is not supposed to be below 14 psi. Im at 5 psi and the dealer was trying to say that's normal. I talked to a coupl other mechanics and they said its not, and it may be an internal oil leak causing the pressure to drop but not the level. I made another appt at the dealership. Do you guys think the extended warranty company will give me **** about my cai, hfc's, and catback exhaust if it is an internal oil leak?
09-25-2012, 11:10 AM
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Well had it in at the dealer 4 times. They replaced my gauge and sending unit. It's still reading way low. The mechanical pressure gauge they hooked up is also low. They are telling me I'm basically out of luck because I installed a switch to disable the vdc and I have a tech sticker from a car club on the window (even though I never raced the car) they are telling that there is nothing more Nissan can do. I don't see how installing a different type of switch for the vdc would have any effect. Any suggestions?
09-25-2012, 12:31 PM
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Well had it in at the dealer 4 times. They replaced my gauge and sending unit. It's still reading way low. The mechanical pressure gauge they hooked up is also low. They are telling me I'm basically out of luck because I installed a switch to disable the vdc and I have a tech sticker from a car club on the window (even though I never raced the car) they are telling that there is nothing more Nissan can do. I don't see how installing a different type of switch for the vdc would have any effect. Any suggestions?