Loud engine tapping

BEAUB1980

MEMBER
1994 OLDSMOBILE CIERA
3.1L
6 CYL
2WD
AUTOMATIC
83,421 MILES

I drove home last night in a perfectly running car. Oil changed early usually. Just changed eight hundred miles ago. I get in my car this morning to head to work, I start it and it is making a horrible chattering tapping noise. I shut it off instantly. Check oil and it is full. Get in car say a silent prayer hoping I would not hear it again and it was the same. I shut it down instantly. That is where I am at. No idea what to check. Can you check oil pressure without it running? Can a pump just fail over night? What could have happened just sitting there? It drove home perfect the night before with not a noise at all. In fact it ran so good you could not tell it was running at idle. Please any input would help.

Monday, December 3rd, 2018 AT 6:52 PM

6 Replies

JACOBANDNICKOLAS

MECHANIC
110,176 POSTS

Hi and thanks for using 2CarPros.

It is unlikely that the pump just failed. However, pressure cannot be check without the engine running. Was the oil light staying on?

Now keep in mind, the noise may not even be the engine. It could be one of the belt driven accessories. Open the hood and make sure the serpentine belt is not frayed or excessive loose. I attached a picture of the routing. If it is tight, remove it and check all belt driven accessories for excessive play or bearing noise.

Next, about a year ago, a customer came in with the same type vehicle that had a knock. It sounded like the engine was done. After diagnosing it, I found the harmonic balancer was bad. There is a rubber molded mount between the base that is bolted to the crankshaft and the outer portion of the balancer. I replace it and the noise was gone.

If you remove the belt, start the engine for a couple seconds to see if the noise is gone. That will tell us a lot.

Let me know what you find or if you have other questions. Also, have a helper start the engine while you confirm the noise is coming from the engine.

Take care,
Joe

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Monday, December 3rd, 2018 AT 8:29 PM

BEAUB1980

MEMBER
5 POSTS

I took the belt off and the same sound is there. I really do not understand how a perfect running car that has never had any issues, never had a light on just fails sitting there over night. Could I take the coil wire off and just turn it over and check the oil pressure or does it need to be running? I have another car and motorcycle so I can try and tinker with it. I have way too much money in this car to give up. I know it is not valuable at all but I really have changed every accessory, sensor, wire, hose, six month old complete AC system, etc. Like $4,000.00 in a car that is worth $1,500.00 only because I read these are reliable cars and it is mint low mileage. I will stick with Ford's panther models.

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Friday, December 7th, 2018 AT 6:18 PM

BEAUB1980

MEMBER
5 POSTS

What are the odds of me changing the oil pump and fixing it? If it failed the night before would a light not come on for low pressure? I look at my dash every ten seconds and it would of been bright at night. I am so confused on this car.

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Friday, December 7th, 2018 AT 6:34 PM

JACOBANDNICKOLAS

MECHANIC
110,176 POSTS

Hi,

You need to have the engine running to get a proper pressure reading. As far as the pump, if the light is not on, there is a good chance that is not the problem. Is it possible for you to record the sound so I can hear it?

Thanks,
Joe

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Friday, December 7th, 2018 AT 8:10 PM

BEAUB1980