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Discussion Starter · #1 ·
So tonight I go through the drive thru and I keep hearing this tic tic tic and then I realize it's my truck. So I start trying to figure it out. Truck is idling at 600 rpm but, if I bring the rpms up to 700 the tic goes away but, if I let the rpms fall back to the 600 idle the tic is there. Any idea what would be causing this? Just for clarification when I say tic I mean it's very light and sounds like a sewing machine tic.
 

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So tonight I go through the drive thru and I keep hearing this tic tic tic and then I realize it's my truck. So I start trying to figure it out. Truck is idling at 600 rpm but, if I bring the rpms up to 700 the tic goes away but, if I let the rpms fall back to the 600 idle the tic is there. Any idea what would be causing this? Just for clarification when I say tic I mean it's very light and sounds like a sewing machine tic.
If the sound is like two metal balls smacking together then it's a bearing noise and I could guess it would be from the idler pulley or the belt tensioner pulley. Now if it's a tick like an engine sound then it can be due to normal valve train ware, I doubt this because the magnum uses hydraulic lifters which have little pistons that push up against the pushrod to assure zerolash after miles of ware set in. Of course they can only keep zerolash for so long.

But I think it's something alot more since then an engine problem, it's probably just some stupid bearing trying to be stupid!
 

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so would that mean its a problem? i might hear a slight tick at idle, but i dont hear anything from in the cab. i have always just counted it as normal operation. if its just a bearing could it be a serious problem?
 

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so would that mean its a problem? i might hear a slight tick at idle, but i dont hear anything from in the cab. i have always just counted it as normal operation. if its just a bearing could it be a serious problem?
Well if it is just a pulley bearing then no it's not that big of a deal however with time that bearing will seize up and you could end up damaging the water pump, alternator, and other accessories on that belt not to mention you will probably snap the belt.

One way to find out if it is a bearing is to shoot some WD40 on the back side of the pulleys and if the noise goes away it's a bearing. Usually it's a idler pulley bearing but sometimes it's the belt tensioner, if it's the tensioner then you're better off replacing the tensioner because they're known to fail after a pulley replacement.

But again I'm not promising you it's a bearing but it's all I can think of right now based on my experience with these magnums.
 

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He means a lifter not a tappet, a tappet is a noise a lifter makes! Anyways besides the point these engines utilize hydraulic roller lifters, the lifters have a little piston that pushes up on the pushrod to maintain zerolash and to keep down valve train noise. Any valve train noise from these engines is usually from a loose rocker arm. But the tick tick sound is so much reminding me of the bearings from the pulleys on the accessories drive system. But check the drive belt system first because it doesn't require you to remove the valve covers from the engine or go through any extremes. Then you can move onto something else, old trucks make noises like old men!
 

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Umm, no. Lift is what a tappet does. The terms interchange. Lifters=Tappets.
If it is a very light noise, it could simply be injector noise. It tends to dissipate above idle. A lifter can "tap" if the oil hole gets gummed up. The lost oil supply allows the lifter to bleed down. The aforementioned plunger loses support and the tapping you hear is that unpressurized lifter bouncing up and down between the cam lobe and the pushrod/rocker arm.
 

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Umm, no. Lift is what a tappet does. The terms interchange. Lifters=Tappets.
If it is a very light noise, it could simply be injector noise. It tends to dissipate above idle. A lifter can "tap" if the oil hole gets gummed up. The lost oil supply allows the lifter to bleed down. The aforementioned plunger loses support and the tapping you hear is that unpressurized lifter bouncing up and down between the cam lobe and the pushrod/rocker arm.
No a tappet is the noise caused by a lifter. If you don't believe me look it up, hect here http://en.wikipedia.org/wiki/Tappet

But whatever, I don't think the tic he is getting is valve train, like I said I recommend he first check out those pullies cause I'm sure you know, these magnums are prone to having pulley bearing failure. Almost every magnum engine I have heard has a clanging bearing from a pulley hell even my idler is ticking (but doesn't tick when you raise rpm's), which is why I think he should shoot some WD40 on the pulley bearing to rule out a bearing noise or a engine mechanical (drive train) noise. Removing the valve covers, the intake manifold, rockers, so on to replace lifters is not only expensive but it takes some time too!
 

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Discussion Starter · #9 ·
I'll try some WD40 and drive it and see if it's still there. Hopefully it will be a simple fix. Heck I guess I could technically just raise the idle a 100 rpm's and it'd go away as well but, I'd prefer to fix the problem correctly.
 

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I'll try some WD40 and drive it and see if it's still there. Hopefully it will be a simple fix. Heck I guess I could technically just raise the idle a 100 rpm's and it'd go away as well but, I'd prefer to fix the problem correctly.
WD40 isn't going to fix the problem, WD40 is just a tool I use to eliminate noisey bearings, it works 99% of the time. You want to try to shoot WD40 on the bearing when the truck is idleing, if the noise goes away then you found your bearing that's if it's a bearing making that noise.
Best of luck to you.
 
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