Renix valvetrain sounds like gravel crusher
11-22-2012, 02:40 PM
#1
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Year: 2015, 2012
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Renix valvetrain sounds like gravel crusher
Hi, all: Daughter's daily driver '87 4.0 rattles for about 5 seconds on startup.
After warming up, engine sounds like a gravel crusher around the valvetrain/head area at fast idle/moderate RPM.
Lifters were replaced about 30,000 miles ago. That helped some at the time.
Using Mobil 1 10W-30 oil with a Wix filter.
It's REALLY loud. How much longer do I have?
Engine is original with about 220,00 miles now.
After warming up, engine sounds like a gravel crusher around the valvetrain/head area at fast idle/moderate RPM.
Lifters were replaced about 30,000 miles ago. That helped some at the time.
Using Mobil 1 10W-30 oil with a Wix filter.
It's REALLY loud. How much longer do I have?
Engine is original with about 220,00 miles now.
11-22-2012, 03:25 PM
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Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
Gravel crusher? Do you have black smoke smelling like fuel from the tailpipe? Did it run like this before the lifter change? The rattle can be normal in the cold weather, mine does it. are the valve springs in good shape.
11-22-2012, 03:39 PM
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Year: 2015, 2012
Model: Grand Cherokee (WK2)
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It's 70* here right now. It always rattles on startup as I mentioned. Was worse before lifter changeout. Main reason lifters were changed was because several were losing their prime resulting in loud tap tap tap.
But it has not had the loud rattling noise at constant RPM until recently.
No black smoke, or smoke of any kind. It'll use about 3/4 qt oil in about 6,000 miles.
It idles and runs smoothly, no missing.
But it has not had the loud rattling noise at constant RPM until recently.
No black smoke, or smoke of any kind. It'll use about 3/4 qt oil in about 6,000 miles.
It idles and runs smoothly, no missing.
11-22-2012, 05:26 PM
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Year: 2015, 2012
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Yeah, I need to check that a little closer when hot. Upon cool start a little while ago, there wasn't really a rattle except at startup.
Generally speaking, idle and running oil pressure has always been within specs on this Jeep.
Generally speaking, idle and running oil pressure has always been within specs on this Jeep.
11-22-2012, 05:34 PM
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Year: 1988
Model: Cherokee
Engine: I6
Check the bolts on your flywheel (flex plate) what err you call it... Mine loosened up on me one time while heelig and it sounded like a pop can
11-22-2012, 06:02 PM
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Year: 2015, 2012
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That's a good hint. But the sound comes from up top, under the valve cover.
It does it worse when warmed up. Not so much after startup.
It does it worse when warmed up. Not so much after startup.
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11-22-2012, 10:59 PM
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Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
loose rings
banging piston skirts
worn out piston pins
oil loss may be the rings I lose about half a quart of oil about every 400mi or so on long drives due to the rings.
banging piston skirts
worn out piston pins
oil loss may be the rings I lose about half a quart of oil about every 400mi or so on long drives due to the rings.
11-22-2012, 11:26 PM
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Year: 90,84
Model: Cherokee
Engine: 4.0,2.5
I saw mentioned you can check the knock sensor by rapping on/by it. And listen for a change. I haven't tried it. Just fielding a thought. I gather the ECU will keep advancing the timing until knocking signals the knock sensor to tell the ECU to knock that off! 
11-23-2012, 12:03 AM
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Year: 2015, 2012
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I hope it's just a weakening oil pump. When I had the head off about 30K miles ago or so, there was very little ring groove and the walls looked clean then.
11-23-2012, 08:15 PM
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Can you post up a link to a recording of that? I did a "test flight" posting on U-Tube and posting the link to that, and it seemed to work OK without much hassle. I suppose "condenser mic" in your device might well deliver a misleading signal...but it's always fun!
That experiment, Here>. ( It's checking injector pulse..on #2.., with a bulb from a three cell mag light) Its missing with #2 's wires disconnected for the 4.5V Bulb? AW phit. its fine. Just with the camera on it's not steady because of the way I'm holding it. It's pulsing fine.
That experiment, Here>. ( It's checking injector pulse..on #2.., with a bulb from a three cell mag light) Its missing with #2 's wires disconnected for the 4.5V Bulb? AW phit. its fine. Just with the camera on it's not steady because of the way I'm holding it. It's pulsing fine.
Last edited by DFlintstone; 11-24-2012 at 12:47 AM.
