1995 Dodge Ram Tappet noise

Tiny
GRIS
  • MEMBER
  • 1995 DODGE RAM
  • V8
  • 4WD
  • MANUAL
  • 14,500 MILES
My engine has a noise that occurs at valve rocker speed. It has been doing it for the last 4000 miles. It sounds a lot like a tappet. At cold idle, it is quite loud. It gets quieter when the engine is completely warm. It gets louder as I first speed the engine up to take off. Then it gets quieter. If you just rev the engine up to about 1500, it gets louder just at first, and then gets quieter. After driving for a short while, when the engine is hot, I cannot hear it at idle. As soon as I push the accelerator down a little to take off, it get louder. As the engine speeds up, it seems less loud, but I think that is because the pecks come closer together, and there is less time for whatever is making the noise to do so. It is very hard to hear at 2000 rpm, but that may be because of the other enging noise. I have had two other mechanics listen to it, but they have no answer.
I have replaced all the cam followers, checked all the pushrods for straightness, inspected all the rocker arms and the blocks that hold them down for clearance and wear. I bought two new blocks and the yoke that keeps them in alignment, as I thought I had discovered a worn place. I looked at the cam position sensor and replaced it about.015 further out to see if it might be the timing chain with a loose spot. None of these things has made a difference…well, the new tappets may be slightly different, but the noise has not gone away. I have not checked the timing chain and gears, but, since the noise is at rocker speed, I thought this was unlikely.
1995 Dodge W2500, V10, 5sp, a/c, 145,000mi, cold idle oil pressure 60#, warm idle, 40#, warm 3000 70#.
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Wednesday, March 18th, 2009 AT 7:23 PM

24 Replies

Tiny
JAMES W.
  • MEMBER
From the way you describe the noise and the rpms at which it comes and goes, it sounds to me like you've spun a rod bearing. What is your oil pressure like at warm idle?
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Thursday, March 19th, 2009 AT 2:06 AM
Tiny
GRIS
  • MEMBER
Did you read the whole questiion? The warm oil pressure is listed at the end of it. It is #40.
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Thursday, March 19th, 2009 AT 6:35 AM
Tiny
JAMES W.
  • MEMBER
Sorry, I missed that part. You mentioned you changed all the cam followers, did you mean the hydraulic lifters? The only thing else I can think of that would cause the noise you describe is timing chain hitting the cover. Grab the crank pulley and move it back and forth to see how much slack you have. You'll be able to feel when the crank trys to turn the cam. Let me know.
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Thursday, March 19th, 2009 AT 2:40 PM
Tiny
GRIS
  • MEMBER
OK. I haven't actually done that. I would have thought that a timing chain slap would not be so regular. This noise is dead even, with no oscillation. I will check your suggestion.
Yes. Lifters, followers. This is the first engine I have owned with roller lifters.
PS, I know about the tree/forest thing.
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Thursday, March 19th, 2009 AT 6:13 PM
Tiny
JAMES W.
  • MEMBER
Even though you'd think the tension on a timing chain would be the same all the time, they will slap when you quickly crack the throttle.
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Thursday, March 19th, 2009 AT 6:42 PM
Tiny
GRIS
  • MEMBER
I put a breaker bar and a socket on the front pulley and wiggled it. Then I turned it some and wiggled it again a number of times. There are some positions where I am sure there is no noise and some where there may be a slight noise. It is hard to duplicate the force that the parts are under when the engine is running. When the engine is running, you can hear the noise if you lie underneath the truck.
I guess my concern is, why is the noise so regular? It also does not sound like a rub, but more a tap. I would have thought chain slap would be irregular? It does get slightly quieter when the engine is fully warmed, but cast iron does not expand much, nor does the steel in the chain.
It does make more noise under slight acceleration, and less under deceleration. I suppose it could be the chain loosening in one case and tightening in the other. I think it is quieter at about 2000 rpm. It also gets slightly quieter after you accelerate and then go to neutral throttle.
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Saturday, March 21st, 2009 AT 3:36 PM
Tiny
JAMES W.
  • MEMBER
When you turn the crankshaft back and forth, your not trying to replicate the "tapping" sound, you're trying to determine how many degrees of slack you have when the chain tightens against the cam. 1 to 2 degrees for an engine with your mileage would be normal. 10 degrees or more would be a lot of wear.
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Saturday, March 21st, 2009 AT 5:25 PM
Tiny
GRIS
  • MEMBER
How would I know how many degrees the crank moves before moving the cam without removing the timing chain cover or the intake manifold? There is way too much internal friction in a V10 to just feel it.
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Saturday, March 21st, 2009 AT 6:34 PM
Tiny
JAMES W.
  • MEMBER
Use your timing marks. Turn the crank clockwise 'til you get the mark on the balancer to "0" or TDC, which ever you have. Then, slowly turn the crank "counterclockwise" until you feel the chain start to move the cam.
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Saturday, March 21st, 2009 AT 8:45 PM
Tiny
GRIS
  • MEMBER
Well, I cannot use my timing marks. The V10 has a crank position sensor in the side of the block, behind the motor mount. The front pulley has no marks on it, only balance holes.
I marked it and ran a straight edge from an oil pan bolt to the radiator shroud. Then I moved the pulley back and forth. If I picked a place where I could hear the noise that I mentioned above, I get about 1/4" movement of the mark on the pulley. If I am doing the calculation correctly, that translates into just short of 4 degrees.
If that means the chain is too worn, I can change it. I have changed Shell Rotella 15w40 and the filter every 3000 miles. You have to wonder what you would have to do to get the chain to last the life of the engine.
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Sunday, March 22nd, 2009 AT 9:08 AM
Tiny
JAMES W.
  • MEMBER
Ya' done good. If that's all the slack you have, the chain's good for another 100K miles. The only other thing I can think of without actually hearing the noise is something that's "belt driven. Have you tried removing the belt(s) and running the motor for a little bit and see if the noise is still there?
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Sunday, March 22nd, 2009 AT 11:09 PM
Tiny
GRIS
  • MEMBER
Removing the serpentine belt makes no difference, whatsoever.
I noticed this noise about 4000 miles ago, but it did not come on slowly. It came on fast. It is a peck or a tap, quite metallic, with no scraping associated with it. It is as if a valve were not closing and the pushrod was coming up and hitting it.
Some listeners have said to just let it go, but I don't like that idea much.
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Monday, March 23rd, 2009 AT 9:26 AM
Tiny
JAMES W.
  • MEMBER
When this "tapping" noise exists, does the engine miss or seem to drop a cylinder?
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Monday, March 23rd, 2009 AT 12:17 PM
Tiny
GRIS
  • MEMBER
No. It runs evenly, and the fuel mileage is the same as it has always been.
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Monday, March 23rd, 2009 AT 3:53 PM
Tiny
JAMES W.
  • MEMBER
Gris, there was a TSB issued for '94-'95 Dodge trucks where they made a tapping/fluttering noise during light acceleration/deceleration. It has something to do with the air intake system. You may want to give your local dealer a call to get more info. Let me know what you find.
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Monday, March 23rd, 2009 AT 9:02 PM
Tiny
GRIS
  • MEMBER
Don't ya love it? My local Dodge dealer just folded. I will check to see if I can get help from the one that is 50 miles away.
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Tuesday, March 24th, 2009 AT 6:58 AM
Tiny
JAMES W.
  • MEMBER
OK, I'll try to send you what I have on the TSB.
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Tuesday, March 24th, 2009 AT 3:58 PM
Tiny
GRIS
  • MEMBER
Thanks. I can find no TSB on line that talks about this sort of noise. I did not get a chance to call the Dodge dealer today.
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Tuesday, March 24th, 2009 AT 6:46 PM
Tiny
JAMES W.
  • MEMBER
Just happened to be passing your site and wondered what was going on.
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Sunday, March 29th, 2009 AT 6:21 PM
Tiny
GRIS
  • MEMBER
I have not been able to find any TSB's that address my problem.
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Monday, March 30th, 2009 AT 6:52 AM

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