I have a 96 with 122K miles on it. I'm having low oil pressure problems. At start up it's fine, around 45-50PSI but after it heats up goes down to around 25. At idle when hot it's basically 0. My mechanic said it needed a new oil pump so I had him install one. Still the same problem. Now he says its the bearings and I need a new engine. Is he right or could it be something drastically less expensive. Keep in mind I'm a total mechanical noob. Thanks. Steve

 

Could be that the mechanic is correct. Or it could be that the pressure sensor is kaput. The sensor is something of a pain to replace but it's a lot easier and cheaper than a set of bearings. There are two sensors at the back of the engine behind the intake and above the bell housing. One feeds the gauge on the dash, the other tells the 'Check Gauges' light to illuminate when the pressure is low. They have different number of wires (one versus two, I think). Do a 'search' using the tab above and you'll find the answer; or buy a service manual for about $100, you'll eventually need it anyway.
Good luck

 

With the exception of my 96 LT4 smoking like a crack-addict and NOW knocking like it's about to blow up, I have the very same conditions. After having a fellow CF member come over and take a look, the first thing he did was pull out the dipstick and saw metal-flake micro specks in my oil on the stick. He strongly believes that I've spun a bearing, I have ~120K on the motor and now in the process of a complete rebuild (383). Not sure if you have or not, but your oil pressure being that low is a VERY Bad thing to continue to drive it, and you might want to seriously consider going into that motor.
I hope this helps

R/Noland

 

Thanks, how much do you think your rebuild will cost?

 

Oil leak(s) is the nbr 1 reason for low oil pressure. Sending unit is my 2nd choice.

 

First - It is reading 0 but do you hear the lifters ticking loudly at idle?

If not throw some 10W40 in there and drive it. The motor would tell you if the pressure was truly at zero

Just my $.02

 

Would this still be the case if you have good pressure at startup and as the oil heats up it then drops to zero?.........I was under the impression with my car that the sensor is reading correctly. I also checked for leaks in the system and on the ground and came up with nil. My problem is that I drove my car home from work (>65 miles) and now it smokes and knocks so bad that I won't even crank the car up.

 

So far the numbers are still being tallied as we speak but I plan on making a post on this part of the forum with the project. I have a high mileage 96 LT4 that I've been collecting parts for a VERY long time in order to do a GS Replica. I did a Hot-Cam kit, got about 1200 miles on the motor and now this. SO when I pull the motor for the rebuild, I will completely go through the entire car and have an extremely durable, refreshed C4. The motor parts to date are ~4827.00 just in parts. That doesn't include my Oil pan and pickup, Block work to prep the 383, Labor (Plenty of Beer, I hope), Porting of my LT4 intake, Lifters (plan on using Cadillac Racing Lifters), Pushrods (1-Piece), Roller Rockers (haven't decided on these yet), custom ground cam, Fuel Injectors (using 42# fords), Flywheel (Single Mass Steel) or my clutch (I need something equivalent to a Spec Stage II at a minimum. The projections on this motor so far are ~530 - 550 CHP (w/10.8cr). My goal was the whoop up on this chick in my club with a C6 Z06 and be a normal DD if I so chose. The guy building my motor is a stand up guy and doesn't want build a motor so crazy that I smoke the tires every time I try to move from a stop. SO, after being here on the forum, asking questions to the guys that have gone before me, making smart decision for me, asking for help and understanding that: 1. The Corvette Forum (IMHO) collectively has the most knowledge base and experience of Corvettes from A to Z on the Planet, and 2. Opinions are like Azzholes, everyone has them and they all stink. SO look for facts vice opinions, be prepared to work through what is BEST for you and after you make up your mind, Ask and ask again. Either way, good luck and if I can help, I will..........just ask!

R/Noland Smith, Jr.
STSC(SS) USN Ret.

P.S. I was SERIOUSLY on the fence about my heads, I was going to send them to AI to be Ported and Polished, but given the turn-around and more questions being asked on the forum, I chose AFR-195 LT4 Comp Ported Eliminators. I now know that the extra $$$ was the best that I could have done for my car.

 

Nice to see an ex-bubblehead out there

 

Thanks ALOT!.............Good to see guys that have "Been There, Done That" around!

Noland

 

Thanks everybody, I appreciate your input. Noland, I'll look forward to your post. All I can say is that my gauge reads low when hot. At idle at a traffic light or any other time for that matter there is no smoke, no knocking, no indication I have a problem. My cars drives as well as it did when I bought it 4 years ago. I don't sense, feel or hear anything different. Even my mechanic says he can't believe it's not ripping itself to pieces. Can any of you guys suggest a way to find out for sure?

 

Before he asked you to commit your money to a new oil pump, did he verify the low oil pressure by testing it with a known good mechanical oil pressure gauge? If not, the most cost effective course of action includes, step one, fire the bone headed mechanic. It is real easy to find people that will gamble with your money.

RACE ON!!!

 

Very easy and cheap test.

 

Change your oil and add Castrol 20w-50. This should only cost you about $12 to check if it happens again.

If your mechanic had the oil pan off, it would have been the perfect time for him to pull off a main cap or rod bolt and check for clearance issues..

 

I'm with Iroc57. Good luck with the rebuild, Chief.

Ever hear the Blocks-O-Wood?

 

I can neither confirm nor deny any encounters with "That country that we will not name" Sonar Systems!

 

Fair enough!

 

sounds like a spun bearing to me.
The guage is obviously working since it shows pressure when cold.
basically the motor is garbage.