Engine question

**hooley17** · 07-10-2012, 03:26 PM

I am looking at a 2000 pontiac trans am. It has engine work done to it. It has a tapping sound in the engine. It doesnt change with rpms. It is always there. Any ideas what it could be. I dont have a video of it

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**pajeff02** · 07-10-2012, 03:42 PM

A noise that does not change with engine rpm? Do you mean that it stays the same volume, or that it does not speed up and slow down as the engine is revved?

**hooley17** · 07-10-2012, 03:45 PM

It doesnt speed up or slow down. And ot stays the same volume

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**pajeff02** · 07-10-2012, 03:50 PM

That's a damn good question then. Rules out most of the usual suspects such as bent push rods, broken rockers, exhaust leaks, or a belt driven accessory issue. Can you narrow down where it is emanating from? You can use a piece of wood as a pseudo-stethoscope. Press one end up against an area on the engine and the other end to your ear. Then move it around to find where the noise is loudest -- being careful not to get snarled up in the serpentine belt!

**hooley17** · 07-10-2012, 03:56 PM

I heard the noise over the phone. It is at a dealer in PA. it is 3 hrs away. Just triing to get an idea before i drove out there to look at it

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**2002ssslp** · 07-10-2012, 04:32 PM

Let us know what it is. I have no idea on this one.

**pajeff02** · 07-10-2012, 04:52 PM

Whereabouts in PA?

**hooley17** · 07-10-2012, 04:57 PM

It is in butler. Mike kelly chevy. The salesman istring to convice me it is a wrist pin

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**pajeff02** · 07-10-2012, 05:02 PM

If it's a rod knocking, it should change tempo with the engine rpm. Maybe you can score a steal on it by agreeing with him.

- - - Updated - - -

Oh, and Butler is just a bit too far of a drive for me to take a look at it.

**hooley17** · 07-10-2012, 05:05 PM

They want 11,900 with 43000 miles. I am afraid it is something worst and then i am spending alot of money to rebuild the motor. I am gonna ask for a video of it and maybe i can post it here first

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**hooley17** · 07-10-2012, 05:05 PM

Thank you but i wouldnt ask you to do that. You are a good man

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**pajeff02** · 07-10-2012, 05:44 PM

$11,900 for a car with a "knocking rod"?! They be smoking some serious crack at that dealership!

I will always help another member on here whenever I can... just how it is. Let us know what else you find out on this one.

**35th-ANV-SS** · 07-10-2012, 06:05 PM

Subscribed. Common sounds are piston slap, rod knock, exhaust leak, bearings in a belt driven accessory bad, bent push rod and a loose spark plug wire which could be causing an arc.

About all I can add for now until maybe I hear it.

**hooley17** · 07-10-2012, 07:19 PM

There is a boost gage in the car. the sales man said there was no turbo. Could the turbo be in the back under the car and the sound be the blow off? never had a turbo car. couldn't think any other reason you would need a boost gauge. Not trying to sound dumb.

**FinZ28** · 07-10-2012, 08:20 PM

Originally Posted by hooley17

There is a boost gage in the car. the sales man said there was no turbo. Could the turbo be in the back under the car and the sound be the blow off? never had a turbo car. couldn't think any other reason you would need a boost gauge. Not trying to sound dumb.

Are you sure it's a boost gauge? If so, the car either has a turbo or a supercharger, at least I would think (unless it's for show). You can mount a turbo on the bottom of an F-body, towards the rear of the car. You typically won't hear a blow-off valve (which is mounted on the intake side-a wastegate is mounted on the exhaust side but essentially serves the same purpose) at idle, since little boost would be present to cause it to open. It won't make a tapping sound, either. I would liken the noise of a blow-off valve to something like a whistle-hiss type sound. Did you by chance take any pics of the car, or does the dealership have a page where we can take a look at the car?

Edit: I found it. Can't view the pics on my end, other than the thumbnails. You would think they would reset the SES light. Also, at least from the blurry pics I saw, I didn't see any extra piping to indicate the car has either a supercharger or turbocharger. The car looks pretty nice, but the noise would probably be a deal-breaker not knowing exactly what it is.

http://mikekellyauto.mobi/Pittsburgh/For-Sale/Used/Pontiac/Firebird/2000--Black-Car/9152455/

**hooley17** · 07-11-2012, 09:03 AM

I was thinkg the samething. I have been around supercharged cars. Not turbo. The tapping noise is killing me. As much as i like the car and want to buy it to figure it out. I am very very nervous about it. And dont want to waste the time or money to drive three hours with truck and trailer to look at it

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**FinZ28** · 07-11-2012, 09:21 AM

Do you have a mechanic who might be willing to go with you to look at the car again? If so, I'd take them to look at the car and give it a good once-over before making a decision on whether or not to buy it. Having said that, there are plenty of other nice 4th-gens out there for sale, so it's definitely not the end of the world. Heck, there may be a better car to be had for less money. If you can't pin the noise down and can't get somebody to look at the car, I'd pass.

**bryceslu** · 07-11-2012, 09:21 AM

Think about why this car is sitting at a dealer with 43K miles...one option is the previous owner knew there were issues and wanted to unload as a trade in. Obviously not the only option but definitely worth pondering when a 43K mile LS1 T/A is worth much more in a private sale than what a dealer is going to give.

**FinZ28** · 07-11-2012, 09:36 AM

Originally Posted by bryceslu

Think about why this car is sitting at a dealer with 43K miles...one option is the previous owner knew there were issues and wanted to unload as a trade in. Obviously not the only option but definitely worth pondering when a 43K mile LS1 T/A is worth much more in a private sale than what a dealer is going to give.

Good point. I was thinking about that during my previous reply. Too many variables there. Previous owner may have had something come up (marriage, newborn child, change in jobs, etc) that forced him to dump the car and get something more practical. Or, as you stated, the previous owner knew there were issues and got rid of it the quickest way he or she knew how.

**hooley17** · 07-11-2012, 09:55 AM

I have thought about all of the reasons they traded the car in. I wouldnt pay that price for the car. My cousin own his own race engine shop and thats why i was thinking about this car with the work done to it. I will probly pass on the car. They are sending me a video of the car running. I will post it when i get it.

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