| Author |
Message |
    
Dave Crall (Discoverover)
| | Posted on Wednesday, January 15, 2003 - 04:34 pm: | 
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I have a '96 4.0 discovery with 41K miles. I know that many disco's go through this and need head work, but the knocking/ticking is not loud and can only be heard at idle after it warms up (with greater rpm's I "think" it stops or at least does not get louder) The engine is clean down to the metal under the oil cap and I use half and half synthetic and regular oil. It sounds almost like a diesel. The engine is smooth and performs like new, but I would like to know if this ticking is the beginning of trouble and should be dealt with right away or if it is common for them and it will be fine the way it is. It is also a manual and sees greater rpm's than an automatic? Any advice or ideas is appreciated. Dave |
Robbie (Robbie)
| | Posted on Wednesday, January 15, 2003 - 05:01 pm: |
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sounds like a leak in your exhaust. Either bad gasket between your y-pipe and manifold, or possibly even a crack somewhere around there. check that first. |
Dave Crall (Discoverover)
| | Posted on Wednesday, January 15, 2003 - 05:18 pm: |
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I will check that but it sounds more like metal on metal knocking from the head. Thanks |
Pugsly (Pugsly)
| | Posted on Wednesday, January 15, 2003 - 05:32 pm: |
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Are you sure it isn't just a rattly cat? Would check that first.
They tend to rattle worst at idle once hot. LR has to fix the emission system until [80k?] miles free of charge. |
Tim Ballard (Tballard)
| | Posted on Wednesday, January 15, 2003 - 07:07 pm: |
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I have a 96 Disco with 90K, and have on occassion noticed the knocking at start up. It's most pronounced when under load at start up(backing out of the driveway)in cooler weather. It has always gone away and has not gotten any worse, so I have long since stopped worrying about it. |
Dave Crall (Discoverover)
| | Posted on Wednesday, January 15, 2003 - 07:49 pm: |
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I will check the cat, and it doesn't start tapping until its warmed up. I don't remember hearing this in the summer, but that probably has nothing to do with it. I hope mine goes away like yours and isn't serious. Under load there is nothing that I can hear, maybe the increased pressure and oil pressure with higher rpm's stops it. It always taps at idle.
Thanks, |
OLIVER CLOTHSOFF (Everythingleaks)
| | Posted on Thursday, January 16, 2003 - 09:46 pm: |
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May be rocker arms. This is a common problem with rovers and the tick is only there at idle. The tick normally gets louder when the engine is warm. The problem is the steel cap in the aluminum rocker arm comes loose and makes that "lifter style" noise. Rocker arm shafts were only around $70.00 a side last I checked from the dealer. You could remove the valve covers and listen around to pinpoint the noise. If you suspect the rockers try to press down on the back of the noisy rocker and see if the noise quiets down. |
Dave Crall (Discoverover)
| | Posted on Friday, January 17, 2003 - 02:33 pm: |
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right, one rocker must be worn out and have a gap between it and the pushrod (?) |
OLIVER CLOTHSOFF (Everythingleaks)
| | Posted on Friday, January 17, 2003 - 07:34 pm: |
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What actually happens is the steel cap comes loose and proceeds to become a battering ram against the aluminum rocker arm. This eventually gives it more space to make noise.
You can also check the rocker arm cups by removing the rockers and inspecting the cups. If you can twist one inside the aluminum housing ( i normally use a screwdriver to twist) or can see more wear in one than the rest the rockers are faulty. Would recommend replacing both sides at one time because if one bank did it the other will sooner or later. LR has had at least 3 bulletins on rocker arm noise. |
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