How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask AMEDEE Your Own Question
AMEDEE
AMEDEE, CHEVY TECHNICIAN
Category: Chevy
Satisfied Customers: 24393
Experience:  ASE certified tech ADVANCED LEVEL SPECIALIST. Wisconsin certified emissions state inspector
279429
Type Your Chevy Question Here...
AMEDEE is online now
A new question is answered every 9 seconds

Chevrolet 4.3 L low oil pressure

Customer Question

Chevrolet 4.3 L low oil pressure
Submitted: 6 years ago.
Category: Chevy
Expert:  Ron Z. replied 6 years ago.

 

Sounds like you may have a faulty Oil Pressure Switch. It's located at the rear of the engine.

graphic

Customer: replied 6 years ago.

That switch can't detect the difference between 4 and 3 and 1/2 quarts.

 

There is something goofy about the level of the oil in the pan. Something is getting unported starting at 3 and 1/2 low. But I've rebuilt many small block Chevies and the oil pump pick up on the bottom of the pan should be ok down to 1/2 a quart.

Expert:  AMEDEE replied 6 years ago.

Hello!

 

New Expert here!

 

Welcome to Just Answer! My name is AMEDEE. I will be happy to help you out and your 100% satisfaction is my goal. Please realize that all my answers are based solely on the info that you provide me with....

When the oil pressure drops to "0" according to the oil pressure gauge on the dash, does the engine start to make noise as if it were out of oil?

 

 

Customer: replied 6 years ago.
Yes. The lifters start to clatter.
Expert:  AMEDEE replied 6 years ago.

Ok... so it in fact is actually loosing oil pressure... its not just the gauge saying the oil pressure is getting low...correct?

 

Do you have a VIN "W"

 

 

Customer: replied 6 years ago.

Correct. The pressure goes down when the oil level gets below 3 and 1/2 qts.

 

There is a W at about the 8th character in the VIN.

Expert:  AMEDEE replied 6 years ago.

Well, if the oil pressure is in fact going low when this happens, then you either have a bad oil pump, plugged oil pump screen or bad engine bearings loosening up causing low oil pressure. The most common thing that has been known to happen with this engine is the cam bearing slipping off. You can remove the intake manifold and look down into the valley to see if one is hanging out.

If the the cam bearings are ok, then I would check the oil pump and screen.

Customer: replied 6 years ago.

The condition of the cam bearings would not vary with 1/2 qt of oil

 

Since it is fine with a full crankcase, I'll not be taking things apart. Maybe the pump is tired and the slightly higher pressure of a full crankcase makes it work ok.

 

But it is like night and day. When the crankcase is full the oil pressure behaves like a new car. When it is down a little it loses pressure.

 

When you reply to this I'll stop bugging you and hit the accept button.

Expert:  AMEDEE replied 6 years ago.

Hi,

 

I would agree. SInce this only happens when the oil starts to get a little low, I would not pull it apart either. I would just keep the engine oil full. Wink

AMEDEE, CHEVY TECHNICIAN
Category: Chevy
Satisfied Customers: 24393
Experience: ASE certified tech ADVANCED LEVEL SPECIALIST. Wisconsin certified emissions state inspector
AMEDEE and 5 other Chevy Specialists are ready to help you