1998 Cobra Emgine noise - Ford Mustang Forum
 
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post #1 of 10 (permalink) Old 06-13-2011 Thread Starter
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1998 Cobra Emgine noise

I have a strange engine noise, sounds like a knocking that speeds up with engine rpm and almost goes away at idle. I checked with a stethoscope and it appears the noise is not coming from the heads or lower block, timing chain area or waterpump. It gets very loud at the tensioner but the noise almost sounds like a rod bearing. The engine was rebuilt 6 months ago with new bearings, heads reworked, timing gears, chains and tensioners replaced. The only old items are the water pump, AC condensor, power steering pump, belt tensioner and idler bearing.Can a belt tensioner pulley make this knocking or clicking noise.

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post #2 of 10 (permalink) Old 06-13-2011
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what about the throwout bearing? Will it stop making the noise if you put the clutch in? and yes it could be a pulley or the tensioner or possibly the fan motor

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post #3 of 10 (permalink) Old 06-13-2011
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Taking the belt off it and starting it would tell you whether the problem is accessory related really quickly.

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post #4 of 10 (permalink) Old 06-13-2011 Thread Starter
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Even with the clutch in the noise is still present. I could remove the belt to be sure.
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post #5 of 10 (permalink) Old 06-13-2011
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It would at least tell you whether it's an accessory problem, or a timing chain problem.

2001 Dark Highland Green Bullitt
[email protected] naturally aspirated on a bone stock 2V longblock

Under Reconstruction for RS275 Drag Radial Class
Pushrods and Powerglide Coming Soon

If it weren't for physics and law enforcement, I'd be unstoppable.
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post #6 of 10 (permalink) Old 06-13-2011 Thread Starter
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I try it tonight after work. Thank you
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post #7 of 10 (permalink) Old 06-17-2011 Thread Starter
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I took off the belt and the noise is still there and progressively getting worse. So far I do not have any issues with the performance of the car. I hope its not a stupid question but with the belt off could it still be the water pump? The only other possibility i can think of is the High pressure Oil pump I installed during the overhaul. I am still hoping it is not the crank or rod bearings. The sound does not appear to be coming from this area. Anybody have any other thoughts.
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post #8 of 10 (permalink) Old 06-17-2011
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It wouldn't be the water pump, since it's turned by the belt. It sounds like you have a timing chain/tensioner problem.

2001 Dark Highland Green Bullitt
[email protected] naturally aspirated on a bone stock 2V longblock

Under Reconstruction for RS275 Drag Radial Class
Pushrods and Powerglide Coming Soon

If it weren't for physics and law enforcement, I'd be unstoppable.
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post #9 of 10 (permalink) Old 06-18-2011 Thread Starter
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The noise got louder like a bunch of bearings in a mixer, the engine performance went down to the point of shutting down like it was hot. I cranked her up this morning, the engine sounds pretty good but the noise is very loud. My Temp gauge has a short in it so it is hard to tell the temp of the engine, so I am not sure she got hot or not, I have checked the fuses, replaced the sensors and still no temp reading on the gauge.
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can you post a video of the sound?
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