Actual High Oil Pressure Help?
11-19-2022, 02:54 PM
#1
New Member
Thread Starter
Join Date: Nov 2022
Location: Pennsylvania
Posts: 2
Likes: 0
Received 0 Likes
on
0 Posts
Actual High Oil Pressure Help?
Recently purchased a 2008 350Z with unknown history, and with ~106k miles.
Has a timing cover leak along with a seep at the valve cover gaskets.
I am not sure if the high oil pressure was present previous as it was trailered home after purchase.
Changed the oil as I was going to let it seep till I could fully get in there and tear it apart.
Changed the oil with 4 quarts of Castrol GTX high mileage synthetic blend 5w30 and a quart of lucas high mileage oil stabilizer.
At start up after sitting in a pleasantly warm garage 24/7, psi is at about 90.
After letting it get to operating temperature only while idling it sits at around 35 psi.
Reving the engine after reaching operating temperature to 3k rpm’s it sits at roughly 110psi.
Manually pressure tested the system reads the same as on the gauge in the vehicle.
The oil level is between the dots on the dipstick so no it is not overfull, even drained roughly a quarter of a quart, no change.
Changed the filter from a K&N (done with the oil change) to a OE filter, no change.
Changed the oil sending unit with an OE, still no change.
The engine looks pretty clean in the areas I can look and shine a flashlight in and the oil I drained out of it I put through an automotive paint filter and it wasn’t chunky or metallic or too sludgy.
Unless this is normal which everyone seems to have mixed information on what psi is “normal”, I’m at a loss.
Any help?
Has a timing cover leak along with a seep at the valve cover gaskets.
I am not sure if the high oil pressure was present previous as it was trailered home after purchase.
Changed the oil as I was going to let it seep till I could fully get in there and tear it apart.
Changed the oil with 4 quarts of Castrol GTX high mileage synthetic blend 5w30 and a quart of lucas high mileage oil stabilizer.
At start up after sitting in a pleasantly warm garage 24/7, psi is at about 90.
After letting it get to operating temperature only while idling it sits at around 35 psi.
Reving the engine after reaching operating temperature to 3k rpm’s it sits at roughly 110psi.
Manually pressure tested the system reads the same as on the gauge in the vehicle.
The oil level is between the dots on the dipstick so no it is not overfull, even drained roughly a quarter of a quart, no change.
Changed the filter from a K&N (done with the oil change) to a OE filter, no change.
Changed the oil sending unit with an OE, still no change.
The engine looks pretty clean in the areas I can look and shine a flashlight in and the oil I drained out of it I put through an automotive paint filter and it wasn’t chunky or metallic or too sludgy.
Unless this is normal which everyone seems to have mixed information on what psi is “normal”, I’m at a loss.
Any help?
Last edited by ahleeyabeth; 11-19-2022 at 03:04 PM.
11-19-2022, 04:15 PM
#2
350Z/370Z Tech Moderator
MY350Z.COM
MY350Z.COM
Couple things to consider since you’ve already changed the pressure sending unit (usually the cause of erroneously high pressure readings).
2nd most common cause for high oil readings: gauge itself is clogged/bad
Another possibility: oil gallery gaskets blown - a fairly common VQ35HR malady BUT, this issue usually results in LOW PRESSURE so I doubt this is your issue.
Good luck.
2nd most common cause for high oil readings: gauge itself is clogged/bad
Another possibility: oil gallery gaskets blown - a fairly common VQ35HR malady BUT, this issue usually results in LOW PRESSURE so I doubt this is your issue.
Good luck.
11-19-2022, 05:10 PM
#3
New Member
Thread Starter
Join Date: Nov 2022
Location: Pennsylvania
Posts: 2
Likes: 0
Received 0 Likes
on
0 Posts
Couple things to consider since you’ve already changed the pressure sending unit (usually the cause of erroneously high pressure readings).
2nd most common cause for high oil readings: gauge itself is clogged/bad
Another possibility: oil gallery gaskets blown - a fairly common VQ35HR malady BUT, this issue usually results in LOW PRESSURE so I doubt this is your issue.
Good luck.
2nd most common cause for high oil readings: gauge itself is clogged/bad
Another possibility: oil gallery gaskets blown - a fairly common VQ35HR malady BUT, this issue usually results in LOW PRESSURE so I doubt this is your issue.
Good luck.
I know i’m going to be cracking into the front timing cover to re-seal it and I want to replace the gallery gaskets even if they look okay as a precaution and maybe even timing components while i’m in there but really wanted to sort out the high oil pressure before I put quite a bit of time and money into the thing.
The last thing I would want is to put it all back together then blow it up with the skyrocketing oil pressure and have to put out outrageous funds for an engine.
Thank you for the quick response though!
11-20-2022, 08:32 AM
#4
350Z-holic
iTrader: (13)
I have relatively high oil pressure too … I have a few factors that probably influence it but I dont necessarily freak out about it.
I’m usually linearlly up to 100psi to 120psi at redline (when the engine is warm) and at start-up I am like 50 psi to 60psi for the first minute or so.
Is there reason to be worried about slightly higher oil pressure?
Friends also question it as well - I dont know??
I’m usually linearlly up to 100psi to 120psi at redline (when the engine is warm) and at start-up I am like 50 psi to 60psi for the first minute or so.
Is there reason to be worried about slightly higher oil pressure?
Friends also question it as well - I dont know??
11-20-2022, 05:52 PM
#5
Recently purchased a 2008 350Z with unknown history, and with ~106k miles.
Has a timing cover leak along with a seep at the valve cover gaskets.
I am not sure if the high oil pressure was present previous as it was trailered home after purchase.
Changed the oil as I was going to let it seep till I could fully get in there and tear it apart.
Changed the oil with 4 quarts of Castrol GTX high mileage synthetic blend 5w30 and a quart of lucas high mileage oil stabilizer.
At start up after sitting in a pleasantly warm garage 24/7, psi is at about 90.
After letting it get to operating temperature only while idling it sits at around 35 psi.
Reving the engine after reaching operating temperature to 3k rpm’s it sits at roughly 110psi.
Manually pressure tested the system reads the same as on the gauge in the vehicle.
The oil level is between the dots on the dipstick so no it is not overfull, even drained roughly a quarter of a quart, no change.
Changed the filter from a K&N (done with the oil change) to a OE filter, no change.
Changed the oil sending unit with an OE, still no change.
The engine looks pretty clean in the areas I can look and shine a flashlight in and the oil I drained out of it I put through an automotive paint filter and it wasn’t chunky or metallic or too sludgy.
Unless this is normal which everyone seems to have mixed information on what psi is “normal”, I’m at a loss.
Any help?
Has a timing cover leak along with a seep at the valve cover gaskets.
I am not sure if the high oil pressure was present previous as it was trailered home after purchase.
Changed the oil as I was going to let it seep till I could fully get in there and tear it apart.
Changed the oil with 4 quarts of Castrol GTX high mileage synthetic blend 5w30 and a quart of lucas high mileage oil stabilizer.
At start up after sitting in a pleasantly warm garage 24/7, psi is at about 90.
After letting it get to operating temperature only while idling it sits at around 35 psi.
Reving the engine after reaching operating temperature to 3k rpm’s it sits at roughly 110psi.
Manually pressure tested the system reads the same as on the gauge in the vehicle.
The oil level is between the dots on the dipstick so no it is not overfull, even drained roughly a quarter of a quart, no change.
Changed the filter from a K&N (done with the oil change) to a OE filter, no change.
Changed the oil sending unit with an OE, still no change.
The engine looks pretty clean in the areas I can look and shine a flashlight in and the oil I drained out of it I put through an automotive paint filter and it wasn’t chunky or metallic or too sludgy.
Unless this is normal which everyone seems to have mixed information on what psi is “normal”, I’m at a loss.
Any help?
The following users liked this post:
icer5160 (11-21-2022)
11-21-2022, 02:41 PM
#6
As GreyZ stated, these engines take a while to fully warm up the oil. Idling for a short 5-10min won't cut it. It takes about 15minutes of solid driving on the freeway before I see the oil at full operating temp, once there it should idle at around 25-30psi and not exceed 90psi at 3k RPM (if my memory serves).
Does the Lucas stabilizer impact the viscosity at all? These engines are equipped with VVT, so I would be cautious about additives that could impact the flow-rate of the oil. I personally prefer BG products and I like/trust their MOA additive.
Cheers!
-Icer
Does the Lucas stabilizer impact the viscosity at all? These engines are equipped with VVT, so I would be cautious about additives that could impact the flow-rate of the oil. I personally prefer BG products and I like/trust their MOA additive.
Cheers!
-Icer
Thread
Thread Starter
Forum
Replies
Last Post