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HELP! - Bad Hydraulic Lifter, Shim, or Rod Bearing Knock ?
My 2003 Pathfinder w/ 89K on a VQ35DE has developed a tick / knock at the #1 cyl (Front cyl. of engine on the driver's side). Yet it is intermittent and is driving me and my mechanic CRaZy. It especially knocks after hard driving conditions (high rpm, & lots of stop & go). I've run high quality (naphtha containing) valve cleaners in 3 successive tanks of premium gas and yet the noise continues. At cold starts - it's not there at all. When hot, if I bring up the RPMs the noise diminishes or goes away. When very hot & at low RPMs it sounds like the rhythmic start of a rod bearing knock. Let it idle for a while & the noise will also diminish & become intermittent. I've run STP in the oil & I thought it went away the next morning - but I was mistaken - it was still intermittent. I've run Mystery Oil in the crankcase thinking it was a clogged oil passage to the rod or lifter - but after 1K miles that hasn't changed anything either. When I place an engine stethoscope on the exhaust header bolt or on the bolt that holds the #1 spark plug wire in place - there is clearly ticking/tapping - but it skips about every third or fifth beat. I briefly thought it was a timing chain knock - but the noise does not seem to be coming from the front cover at all. So, my questions are: 1) Has a rod bearing gone bad? 2) Has a hydraulic lifter gone bad? 3) Is there carbon build up on the valve stem - even after the injector cleaner? 4) Could the valve have kissed the piston & is now bent? 5) Are there shims associated with the cam in this engine and can they be swapped out / adjusted? 6) What the heck am I overlooking? 7) If I remove the #1 wire while the car is running - do I need to ground the plug wire? Also - what should I look or listen for to make a diagnosis? Any help provided will be greatly appreciated. |
#2
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There is a bulletin for lifter noise, but is usually when the engine is cold.
Service Bulletins Nissan Cars There is also a bulletin for a rattle, similar to the one you describe but is for the Camshaft sprocket: 1996-2007 ALL NISSAN MODELS; DTC FOR VARIABLE VALVE TIMING CONTROL FUNCTION
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#3
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Check compression on the cylinders on that side of the engine. I have seen some melt the # 1 piston.
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Hybrid and GTR certified EV certified ASE Master Certified. |
#4
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Did you find the source of the knock?
Hey, Did you ever find out what the source of this knock was? I have the exact same problem on a DOHC V6 engine by "another" manufactuer, and would love to know what you found.
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#5
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what ended up being the cause of the problem ?
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#6
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The original poster described exactly what im experiencing with my 03' pathfinder, I only wish someone had an answer!!
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#7
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check your power valve screws you may have had one or two come out and get sucked into the cylinder. note you have to remove upper intake to inspect
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#8
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Thanks, I actually did this job two weeks ago and all screws were in place.
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#9
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Any chance the problem is your valve lifters?
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Tags |
bad, bearing, hydraulic, knock, lifter, rod, shim |
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