Need Help with oil pressure.

[LeeS97Z28]

Hi Guys!

I bought a 1997 Firebird Formula with 18,493 actual miles. A doctor owned it and never drove it much. He used penzoil in it non synthetic in the car. Under the hood it looks brand new. Inside it looks brand new, and it even smells new.

The only thing that really bothers me is it hold about 20 to 25 psi oil pressure fully warmed up. Car still has Factory thermostat. THe PCM is not programmed for the fans to come on earlier either so it heats up to 225degrees before the fans kick on to cool it down.

I noticed if I turn on the AC it cools it down to 180 degrees it then hold about 25 or maybe a little better oil pressure.

I think the valves are getting enough oil to me because it sounds like other LT1's I've heard running.

Do you think there is something wrong with my motor?

I'm going to get PCMforless to program me a PCM for 160 degree thermostat and I'll change the factory Thermostat to 160 degree thermostat.

I know some folks have LS1 engines which holds much more oil pressure but LT1's and LS1's are much different beasts.


Let me know what you think! Thanks guys. Lee!

[96FirebirdFormula]

Sounds just like my car

[LeeS97Z28]

Hi 96FirebirdFormula!

Yep! mines just like yours except it is white in color. I like it. It is a super car. I had a 97Z28 until May of this year. It got totalled because a driver was coming home from work and fell asleep and almost hit me head on.

So this car is a replacement. It was hard to find

Thanks Lee!

[Injuneer]

When does it show 20-25psi? At idle? GM requires only 6psi at idle for the LT1.

What is the oil pressure, fully warmed up, at 2,000RPM and at 4,000RPM? Rule-of-thumb is 10psi for each 1,000RPM, or 20psi at 2,000RPM, 40psi at 4,000RPM. A "newish" engine should produce higher pressures though.

Have you changed the oil? Do you know what viscosity oil he was running?

[LeeS97Z28]

20 to 25 psi is at idle fully warm with temp at 180degrees and at 20 to 22 at temp 210 degrees. At 2,000 to 3,000 rpm it is 40 to 45 psi and at 4,000 rpm it is about 50 to 52 psi with engine fully warmed up.

I sure hope it is okay because it sure is a nice car. It has mobil 1 fully synthetic 10w-30 in it now.



Thanks Lee!

[Injuneer]

You might want to use the Mobil 1 5W-30. Although it would appear that it has the same high temp viscosity as the 10W-30, the Mobil data sheets show that the 5W-30 has a slightly higher viscosity at 100*C.

[Joe 1320]

Lee,

sounds like your lower rpm pressure is normal. As Fred mentioned, 10 psi per 1000 rpm is all that is required. More than that, additional loads are placed on the oil pump and the drive parts will wear out sooner. Volume is what you want to make sure is up to snuff. Small amounts of oil at higher pressure isn't as good as larger volumes of oil at medium pressure.

[Lee'S 1997 Z28]

Thanks Guys for your help!

It makes me feel better about the car. I tell ya its like brand new car. I had a camaro Z28 1997 model until May of this year. A guy fell asleep and almost hit me head on. He totalled my Camaro. I liked it well but I think I like this car a little better. I have always kinda liked the Trans Am's and Firebirds better.

I think they are more meaner looking than the Z28's but hey I'll take either. I love F-body's always have always will.

Thanks again! Lee!