my oil pressure has always been low and now I am really concerned after changing my oil, (change less then 3,000 miles w/filter ALWAYS and only Mobil 1 5w30) 63,000 miles, no problems runs great, but especially when it is hot and warmed up, temp around 230, my oil pressure can go as low as 19-20 psi at idle. IT DOES spike with throttle to highest I've seen around 46-48psi. Really bizarre thing was when I changed the oil/filter-K&N Filter this time, and very hot conditions, 95-98 degrees/humid, I fired her up and checked everything out idles at around 900rpm the oil is at 20 psi, normally runs at 42 cold. took it for a ride, psi did increase with throttle but rarely goes higher then 42. PARKED in garage, sat for a week, took it out last night, still warm here but cold start the oil pressure seemed better at 42-43 psi..is there something wrong with my oil pump? I read in here many times the '98 had an issue and that most like to run much higher PSI's like 50 or so...PS-never needs oil added between changes, runs really good.

 

Same problem here.... only difference is 101K and a new pump has been installed. Yes the oring is placed right.. its been checked.

 

M1 5w-30 is thin for a 30, try 0w-40 M1. 230*??? ouch. My Z hovers around 180-190 in the high desert of west TX, so did the SS. Only time I saw temps that high on either one was when a plastic bag got sucked up in front of the radiator of the SS. 230 seems kind of hot, something blocking your air flow? Hot temp + thin M1 might cause your pressure to be a little low hot. Our 98s have a gage that actually calls out the temp. But no guarantee it's accurate, so b4 tearing into anything verify with a mechanical gage.

BTW, 3k on syth is a waste IMO. Check this out: http://neptune.spacebears.com/cars/s.../oil-life.html

 

Gage sending unit may be goign bad.

 

thanks to all of you, by the way, the 230 temp did concern me but I need to explain that, it was VERY hot (99 and index weel in the 110's) and it was idleing a lot. when the fans kicked on it dropped pretty quick; furthermore, when it ever got that high and as soon as I moved even to 30mph airflow quickly dropped the temp to 160-180.

I hate taking my Z anywhere, it has been the best car ever and I treat her like a baby. my history with vehicle repairs would frighten anybody. seems mechanics like to plant parts in my car that give out 150 miles from their shop....so I will try to locate this service tech from a year back and have him look at these things you all mentioned, thanks again

 

Your sending unit probably is going bad. Had that happen once when I had the tranny rebuilt in my 94 Z. Mechanics bumped the sending unit and broke it, and it made the guage read real low. Scared the s**t out of me. My 99 reads 41 psi at an idle in gear, and over 70 psi going down the freeway. In the hot, humid Houston weather with 15w50 Mobil 1. 39,000 miles on the car, never missed an oil change. So I would definitely say that there is a problem, but I would check the sending unit first, because it's the cheaper problem to fix.

 

I'm personally not a big fan of the thin oils. These modern engines have tighter bearing clearances and need an oil that will take a load. A 5w30, 0w30 isn't the ticket.

My guys all run 10w40 mobil 1 and no issues.

Pressure sounds low, but nothing for alarm. Yes the oil pumps in 98's were shady at best but I wouldn't open the front of the engine just to change the pump alone. If it starts to change and get lower yet then I would change the pump. Hell while your in there throw a new cam in as well. Make the labor worth a few HP