Stumped on Engine Knock?

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Muscle99

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Mar 31, 2007

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Apr 10, 2007

#1

• Apr 10, 2007

• #1

Car starts fine cold. No knock or noise. Then I take it out and start to drive in 1st. As I reach 2k and up I hear a repeated knock coming from the engine not a tick or clatter but a deep knock. 2nd gear not as loud as first. As long as i dont take the RPMs up high ill hear nothing. When the engine warms up at the middle of the temp gauge. The noise isnt nearly as loud and even moves up higher in the RPM. Took it out today and really got on it to see what i could hear. First gear on a warm engine at about 3500rpm it knocks faster as the engine builds rpm. but not as loud as on a cold engine. The knock will pretty much disappear in 2nd gear by the time its warm no matter how high i take the RPMs. Ideas? 99 4.6 with 64k.

 

blkhorse

Founding Member

Oct 30, 1999

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Apr 10, 2007

#2

• Apr 10, 2007

• #2

sounds like piston slap or wrist pin,if it's an auto check your torq conv.

 

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Muscle99

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Mar 31, 2007

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Apr 10, 2007

#3

• Apr 10, 2007

• #3

its a manual

 

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Muscle99

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Apr 10, 2007

#4

• Apr 10, 2007

• #4

Used a poor mans steth (screwdriver) on the drivers and pass side valve cover on the drivers side i can hear it ticking over and over on idle its a lil louder on the driver side. I rev it up and it knocks very loud at high RPM. Then I rev it again and its not as loud. Could a Spun Bearing noise decrease in volume after the car is warm and rev'd a few times? This is really bothering me.

 

the98stang

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Aug 12, 2005

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Clovis, CA

Apr 10, 2007

#5

• Apr 10, 2007

• #5

Muscle99 said:

Used a poor mans steth (screwdriver) on the drivers and pass side valve cover on the drivers side i can hear it ticking over and over on idle its a lil louder on the driver side. I rev it up and it knocks very loud at high RPM. Then I rev it again and its not as loud. Could a Spun Bearing noise decrease in volume after the car is warm and rev'd a few times? This is really bothering me.

Click to expand...

Pull each injector connector one at a time. If the noise stops, you found the cylinder that is making noise. If the noise does not go away after unplugging the connectors, then the problem is in the valve train, not in the rotating assembly. A spun bearing will cause a rattling noise. A rod knock or piston slap will cause a much louder noise. Either way, I wouldn't drive the car any more, because you might be able to salvage a few parts of the engine.

 

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Muscle99

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#6

• Apr 10, 2007

• #6

the98stang said:

Pull each injector connector one at a time. If the noise stops, you found the cylinder that is making noise. If the noise does not go away after unplugging the connectors, then the problem is in the valve train, not in the rotating assembly. A spun bearing will cause a rattling noise. A rod knock or piston slap will cause a much louder noise. Either way, I wouldn't drive the car any more, because you might be able to salvage a few parts of the engine.

Click to expand...

I did pull all the injectors on the drivers side (where the sound is coming from) and i still could hear a slight knocking with my ear against the screwdriver on the drivers side valve cover. The sound never changed. On a cold engine while manually closing the throttle at high rpms the noise is very loud. But after i do it for awhile and the engine gets warm its not nearly as audible.

 

the98stang

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Apr 11, 2007

#7

• Apr 11, 2007

• #7

Muscle99 said:

I did pull all the injectors on the drivers side (where the sound is coming from) and i still could hear a slight knocking with my ear against the screwdriver on the drivers side valve cover. The sound never changed. On a cold engine while manually closing the throttle at high rpms the noise is very loud. But after i do it for awhile and the engine gets warm its not nearly as audible.

Click to expand...

This leads me to believe the problem is in the valve train. Get a stethascope (sp?) and try to pinpoint the noise. The noise is probably quieter on a warm engine because the oil is thicker. You can also do a compression test to determine which cylinder is the problem.

 

screamin gt

5 Year Member

Apr 9, 2007

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central CT

Apr 11, 2007

#8

• Apr 11, 2007

• #8

sounds just like what I just went through, checked compression today... mines a 99 too btw... I posted another thread on it...

 

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Muscle99

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Apr 11, 2007

#9

• Apr 11, 2007

• #9

Im tryin to DL your clip to see if it sounds the same but its not working.

 

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Muscle99

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Apr 12, 2007

#10

• Apr 12, 2007

• #10

Seems like i have it pin pointed to the drivers side valve cover towards the front of the engine. 5 or 6. Didnt knock when i first started the car but once it warmed up i could rev it and get it to rattle. Oh and the sound almost sounds like a grandfather clock. Cept rapid when RPMs r increased.

 

the98stang

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Apr 12, 2007

#11

• Apr 12, 2007

• #11

Muscle99 said:

Seems like i have it pin pointed to the drivers side valve cover towards the front of the engine. 5 or 6. Didnt knock when i first started the car but once it warmed up i could rev it and get it to rattle. Oh and the sound almost sounds like a grandfather clock. Cept rapid when RPMs r increased.

Click to expand...

Does it sound like a flutter or a TAP? Because when I think of grandfather clock, I don't imagine a load noise. If your car is ticking or fluttering, it might be an exhaust leak or bad lifter.

 

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Muscle99

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#12

• Apr 12, 2007

• #12

the98stang said:

Does it sound like a flutter or a TAP? Because when I think of grandfather clock, I don't imagine a load noise. If your car is ticking or fluttering, it might be an exhaust leak or bad lifter.

Click to expand...

The noise isnt really taht loud. I can hear it inside while driving with the radio off. Its kinda like the tone of a grandfather clock almost sounds like some hard plastic rattling not real tingy like heavy metal. I cant get it to constantly stay rattled. It makes the noise when i pass through certain RPM's. Then If i take it real high in the Rpms it goes real fast. Car is running fine at idle you cant hear it. If i dont take it high in the rpm aka just drive it normally it doesnt make the noise. Im starting to think its maybe a lifter. Ive been driving it like this for 2 weeks and its not gotten worse.

 

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Muscle99

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Apr 14, 2007

#13

• Apr 14, 2007

• #13

Let my mechanic go for a drive with it. He says its not a spun bearing or rod. Said it would barely be driveable and would be much louder by now. Hes not sure but he thinks its either a leak or a lifter or possibly a wrist pin. So i guess thats good news. I have a warranty on the car so hopefully it gets taken care of.

 

the98stang

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Apr 14, 2007

#14

• Apr 14, 2007

• #14

I wouldn't even worry about it dude. Just drive her until she blows!

 

0

01Steeda

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May 29, 2005

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Apr 14, 2007

#15

• Apr 14, 2007

• #15

I have had piston slap on my forged engines and it never became an issue. sometime if the clearances are out even .001 you can get piston slap on these motors... mine has it now... no biggie, just aggrevating

 

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sane4stangs

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Apr 13, 2007

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Apr 15, 2007

#16

• Apr 15, 2007

• #16

have found which cylinder it is coming from? Once you have that done take the sparkplug out and see if it has been damaged if so there is something on top of the piston, what you can do is leave the spark plug out and start the car and 9 times out of ten whatever is in there will shoot out of the plug hole. If thats not the problem then check all your connections to the coils. And if that dont work you got bigger problems

 

K

Kilgore Trout

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Apr 15, 2007

#17

• Apr 15, 2007

• #17

Hmmm, I listened to that and I think it sounds horrible. I do not know exactly where the sound is coming from but it sounds severe and I would not "just drive it" in that condition. Get it checked out in a shop and find out exactly what is wrong. Driving it could cause additional damage/cost.

 

the98stang

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Apr 15, 2007

#18

• Apr 15, 2007

• #18

I havn't heard any sound clip

Can you post it?

 

35thGTLimited

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Mar 10, 2007

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The Pocono's

Apr 15, 2007

#19

• Apr 15, 2007

• #19

If you have a warrenty, take the car back immediately, don't listen to that guy, don't run it till it blows, that's ignorant as hell, besides, the less work you have done to the engine the better. Right now you know most of it is good, but ya never know who might wind up working on the car, and you may get someone who's careless and lazy ripping half your motor apart cause you destroyed it, now you have some jackass putting your engine back together. This is all my opinion, but, I just prefer to keep my engine as ford built it as long as possible, until I decide to mod, in which case I'll choose a mechanic I know I can trust.
It could be something simple. Keep in mind the reason that people say run it, is, well, hah, we all know, with a modular you can have a knock or tick for 75,000 miles and never have a problem, but then you hear a horror story of a guy with 20k blow a head gasket for no reason. IMO, these cars run to 225k easy if you don't mod, and let the car warm up before crossing 2500rpm, and when I saw warm up, I mean, summer time too. I hate seeing people fire it up, pull out and start driving.... Idiots, there's little oil where it needs to be, and temperatures are sparatic, as the engine runs all parts become oiled and share heat, less expansion, also good for gaskets.

Anyways if you have a warrenty, take it to them and let "them" decide what to do. If it's your only car, you can find rentals for dirt cheap, or maybe they can give you a loaner. It sucks only having one car, I went 4 years that way, no more, I got a '97 Explorer sport 4x4, and I'll never sell it!!!!!!!

 

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Muscle99

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Mar 31, 2007

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Apr 15, 2007

#20

• Apr 15, 2007

• #20

I never posted a sound clip so i think the posts confused. My car sounds nothing liket he clip your thinking of. I bought the car off a used car dealer who bought the car off a Carmax. My warranty is one of those jobs where i find my own mechanic. So im taking it to a family friend who i can trust. It could be piston slap who knows. But I have noticed a few tell tale 99 modular notes since buying the car 2 weeks ago. It has the cold startup knock rattle and a differ noise high in the RPM (the one im getting looked at) Its got a purolator junk Oil filter so once i get things taken care of im putting some mobile 1 and a motorcraft filter in. Taking the car in tommorow so we will see how it goes.