Hello all.

I have a 1991 2+2 5spd with 37,000 original miles. The car has always been taken care of very well with all services documented. My concern is the oil pressure... when cold, it's well into the 70psi range, but this morning after driving for 20 minutes, at an idle the pressure dropped and remained steady at around maybe 15psi. Very disconcerting. I have only just purchased the car so I hadn't noticed if this if this the norm. After bring in back up to speed (45 mph), the pressure slowly climbed back up to around 50 psi.

Is such a low reading normal? I find it disturbing and the oil in there now only has about 1500 miles on it. I know the oil in there is 10W30 synthetic and I checked the level just now and it's fine. Do others use synthetic and if so, do you get similar low readings?


Thanks.

 

It's fine.

 

Wow.. 15psi is normal at idle once warm? I have not messed with a VG30 series, but that seems low compared to most engines I know.

 

That's what I thought. I had to go a Nissan dealership to have new keys cut and I asked the guy in service and he said "no problem" and that it isn't unusual for the Z's to get down to around 10psi at idle.

I had an oil change done while there... used synthetic in keeping with the previous owner...OUCH! Expensive.

 

Good to know.

 

i agree. no problem. but i will mention how bad the pressure sending units are. if you ever don't trust your gauge, change that first.

 

that is right mine did the same thing

 

if you havent already, an aftermarket oil pressure and water temp gauges are worth the insurance from 15 year old senders.

 

this reminds me that my old midget would idle with the oil pressure light on. that means below 5 lbs. i think. maybe it was 10. but it didn't have a single tick. and i drove it kinda hard. these are engines known for very big gaps. they need 20W50 and stuff. and bearings wear out after 30,000 miles

 

i am new to the z and i love my car with my life an only driven it for 2 months now i notice that my oil pressure guage at a completle stop sits at 0psi all the way to the left. and as i drive the needle sways lilike i kid ona swing back and fourth. i am very on time with maintenace an nothin is wrong with my car so im thinken its prob my guage . so thanks for postin about it and help answering a question i would of forgot to ask about

 

not the gauge. sending unit. right by the oil filter. mine did the same thing.

 

That also sounds characteristic of a very low oil level too... might want to check that before replacing the sending unit. (If the pump runs dry because there's not enough oil and it all sloshes to one side of the pan during movement, the gauge will drop to 0 and then increase once the oil flows back to the pickup.)

 

indeed. very good catch.

 

Wow....I have a 1991 2+2 5sp NA with 60k miles on it --- you have me beat!!!! But agrees, you dont have a problem -- mine will do the same at times....