Please help diagnose mystery noise...

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bluduk15

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Please help diagnose mystery noise...UPDATE WITH VIDEO FIRST POST

I have a 2003 4WD V8 Limited. On colder mornings below 40F, I hear a knocking or rapping noise when I put the truck in gear.

The noise does not happen when the engine is in park, but only in gear. It soon fades away after about 3-4 min. and does not come back until the truck sits overnight.

I would describe it as sounding like someone put a ziptie on my driveshaft as it does not have a very high frequency and it matches my speed.

Any thoughts?

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<embed width="440" height="420" type="application/x-shockwave-flash" src="http://v5.tinypic.com/player.swf?file=2nlh4kz&s=5"><br><font size="1"><a href="http://tinypic.com/player.php?v=2nlh4kz&s=5">Original Video</a> - More videos at <a href="http://tinypic.com">TinyPic</a></font>
 
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sounds like someone put some baseball cards in your spokes!


Check the driveshaft. There may be something stuck to it.
 
It is the infamous Toyota piston slap. My 2005 has it sporadically, my mom's 2007 GX has it every morning we start it, and my dad's 2006 has it sometimes as well. I have spoken to both the Toyota and Lexus dealer and they said it is nothing to worry about. That is the exact noise I hear on all 3 of our trucks.
 
Piston slap is rather common these days on high(er) performance engines. My 94 Trans Am had it, my 03 Corvette has it as does my 07 Limited.

I hate it, but there seems to be no significant damage possible. I guess we just have to live with it.
 
Last few questions...

1. If it is piston slap, wouldn't I hear it whether the truck is in gear or in park? It only makes a noise when I put it in gear.

2. I've read about a timing chain being loose as also causing a similar noise. Can I use the old broom handle on the engine as a stethoscope trick to differentiate my diagnosis?

Thanks
 
bluduk15 said:
Last few questions...

1. If it is piston slap, wouldn't I hear it whether the truck is in gear or in park? It only makes a noise when I put it in gear.

2. I've read about a timing chain being loose as also causing a similar noise. Can I use the old broom handle on the engine as a stethoscope trick to differentiate my diagnosis?

Thanks
Click to expand...

V8 has a timing belt and it will not make a noise.
I would also agree that if it is piston slap then you should here it in park and in gear until engine warms up.
BTW I have V8 and I do not hear piston slap at all
Do you hear the noise when you are in gear and moving?
 
bluduk15 said:
Last few questions...

1. If it is piston slap, wouldn't I hear it whether the truck is in gear or in park? It only makes a noise when I put it in gear.

2. I've read about a timing chain being loose as also causing a similar noise. Can I use the old broom handle on the engine as a stethoscope trick to differentiate my diagnosis?

Thanks
Click to expand...

Happened to me once as well. When you put it in gear, you are putting stress on the trans, and in turn the engine.
 
It worried me too before I knew what it was..... IT IS PISTON SLAP BABY!


Live a little and enjoy the sexy sounds the V8 makes baby!
 
progress4m said:
V8 has a timing belt and it will not make a noise.
I would also agree that if it is piston slap then you should here it in park and in gear until engine warms up.
BTW I have V8 and I do not hear piston slap at all
Do you hear the noise when you are in gear and moving?
Click to expand...


You are in FORT WORTH TEXAS...you wont get piston slappy without the COOOOOLD FRIGID DAYS like us folks.
 
This morning I was very careful to listen. It only occurred when accelerating. It did not happen when I was in park or backing down the driveway.

However, on really cold mornings I have heard it when I engaged the transmission to back down the driveway.

I'll try to get a good video of it this weekend.

I'm not real worried about it, but I'd like to zero in on the problem and take corrective actions if possible or necessary (within reason).

Thanks for all of the help.
 
bluduk15 said:
... I would describe it as sounding like someone put a ziptie on my driveshaft as it does not have a very high frequency and it matches my speed.
Click to expand...

Is the noise coming from the engine or drivetrain? Could be a universal joint. Hit the zerks with some grease and see if it helps.
 
First how many miles? How long has it been doing this? What oil do you use? What have you done so far?

I would check a couple of things:

1. loose heat shield on cat converter or loose converter
2. some vehicles have exhaust gas manifold valves that clank when cold or are stuck. Check your entire intake/exhaust/emissions system to see if there are any mechanical valves that could rattle.
3. worn out converter can rattle until it hits operating temps.
4. fuel injector click. Try some techron in your tank for 1-2 tankfuls to see if you have a dirty injector. Does your engine oil smell like gasoline?

Piston slap will occur at all cold start ups and continue until the piston heats up and expands to tolerance in the cylinder. It will last longer with colder temps and will be usually unaffected by putting the vehicle in gear or going forward or backward. However, Some aluminum pistons can slap like that when under a slight load.

Piston wrist pins can sometimes make a similar noise but subside when the engine heats up like piston slap.
 
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KB084RUNNER said:
First how many miles? How long has it been doing this? What oil do you use? What have you done so far?

I would check a couple of things:

1. loose heat shield on cat converter or loose converter
2. some vehicles have exhaust gas manifold valves that clank when cold or are stuck. Check your entire intake/exhaust/emissions system to see if there are any mechanical valves that could rattle.
3. worn out converter can rattle until it hits operating temps.
4. fuel injector click. Try some techron in your tank for 1-2 tankfuls to see if you have a dirty injector. Does your engine oil smell like gasoline?

Piston slap will occur at all cold start ups and continue until the piston heats up and expands to tolerance in the cylinder. It will last longer with colder temps and will be usually unaffected by putting the vehicle in gear or going forward or backward. However, Some aluminum pistons can slap like that when under a slight load.

Piston wrist pins can sometimes make a similar noise but subside when the engine heats up like piston slap.
Click to expand...

I'm at 110k miles on 2003 V8 Limited. I drive alot and also tow a small trailer with a four wheeler. I've used Royal Purple religiously after engine break in. I thought it might be something loose too as I wasn't quite convinced it was piston slap.

This started this winter and happens when it gets below 40 deg. overnight. This was a 35 deg. morning and the truck was out all night in heavy cold winds.

Heating up definitely affects it because it goes away within a minute.

Thanks for the suggestions, I'll get under there tonight and make sure everything is tight.
 
bluduk15 said:
I'm at 110k miles on 2003 V8 Limited. I drive alot and also tow a small trailer with a four wheeler. I've used Royal Purple religiously after engine break in. I thought it might be something loose too as I wasn't quite convinced it was piston slap.

This started this winter and happens when it gets below 40 deg. overnight. This was a 35 deg. morning and the truck was out all night in heavy cold winds.

Heating up definitely affects it because it goes away within a minute.

Thanks for the suggestions, I'll get under there tonight and make sure everything is tight.
Click to expand...

If the engine has been quiet up until now I doubt it is piston slap after 110k miles now. Could it be detonation? What type of gas are you using? When was the last tune up with new spark plugs?
BTW, I believe your engine has a timing belt. Has that been replaced yet?
 
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