Tapping sound from engine and check engine light is on

Tiny
CHEVY73
  • MEMBER
  • 1999 CHEVROLET TAHOE
  • 5.7L
  • V8
  • 4WD
  • AUTOMATIC
  • 135,000 MILES
Hey there. I have the SUV listed above with a vortec 5.7 350. My thing is it was a tapping sound can't really tell if it a bottom noise or top end. No antifreeze in oil to say. I changed oil but some stop leak in radiator still squealing then stops. Check engine light is on now the antifreeze ran back to the back up. I think it needs a water pump. Also and change thermostat and low oil pressure.
Wednesday, October 14th, 2020 AT 1:33 PM

4 Replies

Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Good afternoon,

Did you check the actual oil pressure? You remove the sender unit and insert a manual gauge in and run the motor.

https://www.2carpros.com/articles/high-or-low-engine-oil-pressure

As far as the noise, can you upload a video so I can hear that noise?

I attached the process for checking the pressure below.

Roy

REMOVAL PROCEDURE

Tools Required
J 41712 Oil Pressure Switch Socket

imageOpen In New TabZoom/Print

1. Disconnect the electrical connector.
2. Hold the engine oil pressure sensor fitting with a wrench.

IMPORTANT: Note the alignment of the oil pressure sensor fitting prior to removal.

3. Remove the engine oil pressure sensor using J 41712.

imageOpen In New TabZoom/Print

4. Remove the engine oil pressure sensor fitting, if necessary.

Oil Pressure Diagnosis and Testing

1. With the vehicle on a level surface, allow adequate drain down time, 2-3 minutes, and measure for a low engine oil level.

Add the recommended grade engine oil, and fill the crankcase until the oil level measures FULL on the oil level indicator.

2. Operate the engine and verify low or no oil pressure on the vehicle oil pressure gauge or the oil indicator light.

Listen for a noisy valve train or a knocking noise.

3. Inspect for the following:
Engine oil diluted by moisture or unburned fuel mixtures
Improper engine oil viscosity for the expected temperature
Incorrect or faulty oil pressure gauge sensor
Incorrect or faulty oil pressure gauge
Plugged oil filter
Malfunctioning oil filter bypass valve
4. Remove the oil pressure gauge sensor or another engine block oil gallery plug.
5. Install an oil pressure gauge.
6. Start the engine and then allow the engine to reach normal operation temperature.
7. Measure the engine oil pressure at the following RPM:

Specification
7.1.42 kPa (6 psig) minimum, at 1,000 RPM
7.2.125 kPa (18 psig) minimum, at 2,000 RPM
7.3.166 kPa (24 psig) minimum, at 4,000 RPM

8. If the engine oil pressure is below minimum specifications, inspect the engine for one or more of the following:
Oil pump worn or dirty
Malfunctioning oil pump pressure relief valve
Oil pump screen loose, plugged, or damaged
Excessive bearing clearance
Cracked, porous or restricted oil galleries
Engine block oil gallery plugs missing or incorrectly installed
Broken valve lifters
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Wednesday, October 14th, 2020 AT 2:17 PM
Tiny
CHEVY73
  • MEMBER
  • 2 POSTS
Okay, I will try that. Can't send sound system not set for it but I have it.
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Wednesday, October 14th, 2020 AT 2:49 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
You can email it to me if you wish.

Roybelding@gmail. Com.

Roy
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Wednesday, October 14th, 2020 AT 2:54 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Wow, that is a bad noise.

It sounds like something in the lower end of the motor.

I would suspect you will be either rebuilding the engine or replacing it with another engine.

Roy
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Wednesday, October 14th, 2020 AT 3:32 PM

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