Hello everyone. I know there are a number of "low oil pressure" threads but after reading a number of them, i still have yet to fix my problem. So my Z is an 08 with 42k and only gets driven in warm weather months mostly on the street but occasionally on track. Anyway after bringing it out for the first time after winter i noticed the oil pressure gauge reading pretty low. At idle when warm the gauge is a hair above 0 (maybe 4-6psi). At 2k rpm the gauge is barely at 30psi and on a hard pull the gauge reaches about 85psi at 5k rpms and is stuck there until redline. After reading other threads i decided to replace the Oil pressure sending unit but that did nothing. I haven't been able to get a gauge to hook directly in the port yet but i am still a bit concerned. Car seems to be running ok but i know those readings are way below "acceptable limits" as stated in the FSM. Could my actual gauge in the car be bad? Its weird that this problem occurred after bring stored for the winter (car was ran weekly). Could the oil pump be going bad? Any help would be appreciated. Thanks in advance.

 

I had low oil pressure like that when I had my krank vent installed. The vacuum was fighting the oil pump. It literally threw my pressure off by 20-25psi.

Try starting the car and remove the oil cap and check the oil pressure.

Have you changed your oil yet?

 

I will try that suggestion. I dont know how that could be the problem because i didnt do any work like that but its worth a shot. Yes oil was changed a month ago with mobil1 5w 30.

edit: tried the suggestion and it didn't work. I noticed that the gauge reads "normal" for the first 5 min of driving or so and then I start getting low readings when the engine really warms up. I am lost at this point. short of dropping the pan and looking at the oil pump, I'm not sure what to do. I plan to track the car more this year but I don't want to unitl this problem is sorted out.

 

Any other suggestions?

 

Not sure but if you had any other z friends. Try switching the gauge cluster. My friend's Z had low/erratic oil pressure. When I put my gauge on it worked fine.

Other then that, try a mechanical gauge as you mentioned earlier.

 

10 PSI per 1000rpm should be fine and nothing to worry about.

 

I disagree. In the domestic world that was a rule of thumb years ago. If there is no strong vacuum in the crankcase and he has 4-6 psi @ 650rpms, there is something wrong unless he is running water.

Most of the Z's I've driven are around 25psi at idle, ~60psi at 2.5-3krpms. This car has a timing chain. Low of oil pressure at idle is not good and on some cars this can result in a skipped timing chain. There is either a leak before the oil pump, the oil pump isn’t sealing, a main is bad. Sounds like bringing up the rpms will overpower the leak.

If the oil pressure gauge is completely consistent, he has an issue.

 

I am buying a pressure gauge and going to hook that up. I need to figure this out. I have a friend with a Z but he doesnt want me messing with his gauges. Its starting to get on my nerves. I have noticed the last few times driving it on a cold start-up the psi barely breaks 60psi. Hopefully its a bad gauge and not a leak.