540 vette

I did when I had the car running in my driveway. It would get to 216 and then go down to 210.

Whodamans

So i had similar issue but worse. I would be fine at startup 30+ psi and as it warmed up i would hit 13 psi at hot idle. Pressure jumped right up with RPM's but idle was bad.

Turned out to be a scorched rod bearing. I think the vast difference from startup to warm is the oil thinning out exploiting that extra clearance the bad bearing was giving it.

I also noticed i ran MUCH higher temps until after the rebuild i can push it and still not break 200 degrees. I upgraded to a high volume pump, Oil actually does a massive amount of cooling under normal driving.

A lot of things can cause low oil pressure in the LS engine, oiling system is its Achilles heel. They all require pulling apart the engine. Easiest to check outside of a bad sensor (also most unlikely) would be your AFM tower o-rings. Pick up tube o-ring is fairly common, main bearing/rod bearings, pick up screen oil pump itself, the barbell, ive even heard the lifters themselves can wane out their guide holes in the heads.

Lots of people will tell you that you are fine (even GM who claims 6psi is within spec, wtf) which at 20 you "probably" still are, for now. You are right on the edge of a problem if you ask me. That being said its a 05? how many miles? it could be perfectly normal for 100k+ miles, everything is just a little worn and its no specific problem. Mine had 19k miles, so i definitely had a problem.

540 vette

29,000. The whole problem is you get a whole bunch of different answers. And they are right because every car is different. Some say the temp is fine, others say the pressure is good. Then others like yourself seem to think there might be a problem.

FatsWaller

The OEM t-stat starts to open at 187°. It should be fully open at 195°, at which point it’s no longer in play. If you saw temps cycling between 210 and 216, that’s more likely the fan ramping up as the temps increased, and pulling the temperature down. You can see that in the fan table posted above. I suppose the t-stat could be out of spec, but that’s not the normal failure mode. They usually stick open or closed, and rarely somewhere in between. Airflow through the rad is the determining factor, though. I’ve got a DeWitts rad that supplies 50% more cooling capacity, but I can still run the temps up to 223° on a stinking hot day stuck in traffic with the AC on full. Mind you, that rad pulls the temps down pretty quickly with the fan running at 90%, so that lessens the overall duty cycle of the fan controller, connector, and fan motor.

VetteVinnie

I'm surprised no one has asked you this, but is the car stock or modified? I've had both, and those temps and pressures vary wildly depending on ambient temperature, underhood temperatures (exacerbated by headers), fan curve settings (if tuned), etc., etc. Probably the best cooling I've seen in my Vettes was when running E85 in my ZR1. That car rarely got over 195 deg on the coolant temp even in 100+ degree heat and spirited driving. Of course, the mileage sucked with E85, but I didn't care.

Here's an experiment I did with my bone stock 2011 Grand Sport when someone else was expressing concern about oil pressure. As for personal experience, the flags didn't go off for me until the pressure dropped below 10psi in my 2008 Z06, and that turned out to be an incorrect grind in the aftermarket cam lobes. I noticed it while driving away from the shop that just did the cam and tune.

EDIT: Side note, both my previous Vette and this one had a complete fluid swap front to rear in the first week of ownership because I didn't want to have to guess how long they'd been there or what they used.

After a 10 minutes wide-open throttle spirited drive, at idle in the driveway afterwards: 100 deg outside ambient temperature, 221 deg coolant temp, 243 deg oil temp, 23 psi with fresh 5W-30 oil change (less than 500 miles).

540 vette

Just took the car on the parkway. 62 degrees outside.temp. Cruising at 70. RPM's around 1500. Coolant temp went between 190 and 194. Oil pressure stayed around 40-45 PSI. Oil temp was around 195. Got off to turn around and stopped at a light coolant went to 198. Going back home was the same. Got off the parkway and drove through my area and the temp climbed to 206 and oil pressure was 37. Just before i shut the car down oil pressure was 37, coolant was 206 and the oil temp was 199. I am going to change out the oil as soon as I can.

540 vette

Car is all stock except for a Borla exhaust.

FatsWaller

Based on those observations, your cooling system seems fine. Report back on the oil pressure after you get the oil changed.

540 vette

Tes sir.

Whodamans

Nail on the head my dude. With 29k miles i would say more than likely you have a problem. Again, every car is different but i would say a much great than 50% chance, with those miles, something is wrong. Not astronomically wrong like i was, but whatever it is, its started.

Sorry, i hate to say it I know its not what you want to hear.... That might be part of the reason some guys will just say something generic like "its fine, drive it like you stole it" they dont want to be the bearer of bad news and/or its just not their car, what do they really care.

540 vette

Like what in your opinion started. Are you a mechanic.

Whodamans

Weekend mechanic, by no means a professional.

If you had 100k+ miles it would just be everything wearing tolerances getting wider. The checklist i went through, off the top of my head.

AFM towers have a Oring could be leaking some pressure down
Barbell could be worn
Oil pump could have an issue
Main bearings/rod bearings didn't get enough oil for whatever reason and have some wear
Oil pick up tube Oring could be crushed or warped and leaking down

Its really hard to say having not been with the car. Do you rag on it? was it a GS or Zo6? base model has a wet sump that can starve on oil if you hit a long sweeper corner while also maybe being low on oil, really hard to do with street tires.

540 vette

Base car. Never beat on it. I'm going to change the oil. I don't know what oil the dealer put in there. I am sure it's not a quality oil. I have read it can be any of those things. And it can be normal. I have done a lot of reading on this the last few days.

jjfabs

That is all normal.

StayinStock

I've worked on a ton of LS motors in the last 20 years... I've seen oil pressures range wildly on those. I'd say as long as its not dipping into the low teens you have nothing to worry about (especially at hot idle). Change your oil, see where its at. My original LS1 in my c5 would idle around 18-24psi stock and that motor took plenty of abuse. It later got a 330k 5.3 that would idle around 20, that motor saw around 20lbs of boost and held together for 2 years. These things are way tougher than we give them credit for.