How can I stop engine noise

Tiny
JOE1953
  • MEMBER
  • 1997 CHEVROLET LUMINA
  • 176,000 MILES
My engine make a noise when I step on gas sound like it could be a rod or main bearing noise, is there anything I can put in my crankcase to stop the noise?
Thursday, June 14th, 2012 AT 2:36 AM

11 Replies

Tiny
CARADIODOC
  • MECHANIC
  • 33,873 POSTS
No "mechanic-in-a-can" is going to fix a mechanical problem. First you have to determine the cause to know if it's serious or not. Loose or broken vibration dampers are becoming more common an all car brands and can make a loud knocking noise. That is relatively not serious. If the engine bearings are worn enough to make noise, you should have low oil pressure too. That is only going to get worse real fast.
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Thursday, June 14th, 2012 AT 3:29 AM
Tiny
JOE1953
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When I start the car up it take about one minute for the oil Light to go out, I check the oil pressure it show 37 pound, is that low oil pressure?
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Friday, June 15th, 2012 AT 2:27 AM
Tiny
CARADIODOC
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37 is fine as long as it is nearly that high when the engine is warmed up. That suggests the sending unit is defective which is not uncommon, but that doesn't explain the noise. At high mileage you could have a sloppy timing belt or chain, depending on which engine you have, that is slapping against the cover. The best would be to have a mechanic listen to the noise to give you an idea of the cause and whether it could turn serious.
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Friday, June 15th, 2012 AT 4:33 AM
Tiny
JOE1953
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The noise is is not real loud, but it take about 60 second for oil light to go out. How long it suppose to take for the oil light to go?
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Friday, June 22nd, 2012 AT 4:10 AM
Tiny
CARADIODOC
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Just a few seconds. If you have 37 pounds of oil pressure, the light should go out right away. If it doesn't, I'd suspect the sending unit is defective.
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Friday, June 22nd, 2012 AT 4:29 AM
Tiny
JOE1953
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What will be the best thing to do sell the car and buy a good use one or fix this one if it the oil pump or engine bearings? I will pay up to $1000 to $2500.
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Friday, June 22nd, 2012 AT 5:47 PM
Tiny
CARADIODOC
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Buying a different car is usually not a good solution because it will come with all kinds of new problems you don't know about.

The least expensive route for this problem is to let a mechanic do some tests first. If the oil pressure really is okay right after starting the engine, it may just need a new sending unit. Those are cheap. Oil pumps usually are not the cause of low oil pressure. Worn engine bearings would be more likely. Those can be replaced if no other damage has taken place yet but it's somewhat involved and could take the better part of an entire day. Your mechanic can advise you if that is an acceptable solution and what it would cost. I doubt that would cost $1000.00.
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Friday, June 22nd, 2012 AT 7:08 PM
Tiny
JOE1953
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What cause worn engine bearings? Suppose the crankshaft is worn to?
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Saturday, June 23rd, 2012 AT 3:27 AM
Tiny
CARADIODOC
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Bearings can wear faster than normal from too few oil changes, raw fuel running down the cylinder walls from a leaking injector or some other no-start condition that floods the engine, and diluting the oil, or just high mileage. Antifreeze from a leaking head gasket will dissolve the first layer of metal which is very soft.

The crankshaft journals are hardened and normally wear much slower. If the first layer of metal is peeled away from the bearings, that can gouge the journals and scratch them. Those scratches will destroy new bearings. Even when there are no scratches, the journals can be worn undersize. It may be possible to just install new bearings which will increase oil pressure, but the clearance has to be measured first, then the correct undersize bearings are installed. The common undersizes are.001", .002", then.010" and.020". The.010" and.020" undersize bearings are used when a scratched crankshaft has been machined. The smaller undersizes are used when you don't have to machine the journals.

The clearance for each bearing can be measured with "Plasti-Gauge". That is a small string of putty that is inserted between the bearing and journal. When the bearing cap is installed, the putty squashes out and gets wider, then its width is compared to a chart that corresponds to the clearance. It's actually very accurate.

By measuring the clearances and inspecting the condition of the journals, your mechanic will be able to advise you if simply replacing the bearings is practical and will be beneficial.
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Saturday, June 23rd, 2012 AT 6:11 AM
Tiny
JOE1953
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How much it cost to replace bearing? Do you have to pull the engine out? I supose that can cost a lots of money.
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Saturday, June 23rd, 2012 AT 6:43 AM
Tiny
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Bearings can usually be replaced without removing the engine. Cost is hard to estimate because there's too many variables. I replaced the crankshaft and connecting rod bearings about ten years ago in my '88 Grand Caravan in an attempt to stop a knocking noise. At that time the engine had just over 300,000 miles. The old bearings were fine yet and the knocking noise is still there. I just drove it 60 miles yesterday. That engine is real easy to work on and replacing the bearings only took about three hours, not including changing the oil and some other maintenance I did.

Most shops have to charge around $100.00 per hour. The bearings themselves are not real expensive. I would expect to pay somewhere around $50.00 to $100.00 for all of them along with a new oil pan gasket. Don't forget new oil too.

Why are we even discussing bearings? You said you had 37 pounds of oil pressure. That is fine. Is there something I don't know? Have you tried a new sending unit? What about thicker oil? Any chance your oil got diluted with gas?
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Saturday, June 23rd, 2012 AT 7:10 AM

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