i just hit the 100k mile on my z, i did the full tune up and switched over to mobil 1 full synthetic but the gauge read low oil pressure. when i drive the car pressure goes up but still a lil under normal but when i come to a stop or put the clutch in pressure goes down very low..... i did nothing new from changing the oil same never had this problem but i need help plz

 

OEM nissan filter?
which weight oil?

bigger than OEM sized filters and lower viscosity oils will lower overall oil pressure, especially at higher mileage.

My car has 60k and I use 0w-30 German Castrol. On cold starts, my oil pressure is never above 40psi like ive seen on other VQs. Ive also seen some VQs running off-brand oils that even trigger the low oil pressure dummy light on the dash at idle. Low pressure isnt necessarily a bad thing.

Mobil one is good, just make sure youre getting the right viscosity for your climate/usage.

 

If you're using the same filter and weight that shouldn't be happening. Check your oil level, add if more if needed.

I wouldn't rely on the factory oil pressure gauge to tell me actual oil pressure information...

This might end up being one of those "if it hurts dont do it" things although ive never encountered this kind of issue. Ive always learned if you want your engine to last, use one oil for the life of the engine (post break in).

 

some high compression engines dont like synthetic oil. the viscosity is too low on most of them im guessing. a lot of people disagree but ive seen built corvette engines and race bike engines blow as soon as they got an oil change with synthetic. i only use non synthetic oil, which is half the price, and replace twice as often, also eliminates oil consumption issues of the z, imo.
one of my next mods is a auxilary oil pressure gauge. the stock gauge is not accurate enough.

 

^ exactly....

another note....nissan builds cars, not produce oil - so they design their engines around castrol - they have a contract with them...ie, if you go to the dealer and get oem nissan fluid put in your car - white bottles - its pretty much castrol oil in there..


rear main seal is a rubber compound designed with non-synthetic...

-another note, you have an engine with 100k mile - AND NOW you decide to change it up...the engine is molded/tolerances/wear, etc.....to non-syn....

go back..keep up with it, change it often....look for things like black used oil after a change, increase interval...

better money spent - send a sample off to a lab....adjust accordingly...


-J

 

OP, what oil filter are you running?

Currently running Mobil 1 5w-30 full syn with k&n filter with no issues.

I've read that anywhere between 60-90 on cold starts is normal? Never had a cold start at or below 40psi, seems pretty low.