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10:13 am
Club President
April 2, 2003
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So yesterday I met up with many fellow club members for the Spring Maintenance run.
Some of you noticed an unusual motor noise and commented.
I bowed out of the run, drove home carefully and parked it.
Then I called the local dealership, and have a service appointment for tomorrow morning.
So here is my question - let's speculate!
For those of you there, you heard the noise. What do you think it is?
I'll go first -
I believe I have a broken valve spring.
I also think the oil was overfilled (dealership oil change 200 miles ago). Maybe this contributed to the problem rather than just poor jeep build quality.
The Jeep has 11,000 miles and is 18 months old.
What other guesses do those of you more experienced than me think it could be?
Kathleen and Brad
10:43 am
Club Member
July 15, 2025
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I completely agree. I think it's a broken valve spring.
Tony & Amy
7:00 pm
Club Member
March 5, 2015
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Broken valve spring or bent push rod if it is not overhead cam.
Dale Clement
9:05 pm
Club Member
March 3, 2015
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It's very unlikely that over filled oil would lead to a broken spring. Broken springs usually happen from valve float or fatigue.
It could be broken spring, failing lifter, bent pushrod, or something with the rocker arm. Broken rocker or rocker stud pulling out of the head. Or even the adjuster nut backing off.
Probably not a whipped out cam lobe with roller lifters unless a lifter spun.
Whatever it is curious to find out.
7:05 am
Club Member
May 12, 2023
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Over filled oil can cause the crank case to whip up more oil and "aerate" the oil. Aerated oil may have caused a hydraulic lifter issue, but I don't see that breaking a spring.
My guess it was either a metallurgical defect in the spring material, rocker arm lock down nut loosened up or the adjuster on the valve lossened up.
Dale Mogg - WRZG209
3:56 pm
Club President
April 2, 2003
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Thanks for playing everyone!
The Jeep is in the shop. I will share when they update me.
I don't know if the jeep's oil was overfilled. Being only 200 miles and 0/20 synthetic it is almost clear on the dipstick. So i was guessing as to why this would happen on normal highway driving...
We will see what they say!
Kathleen and Brad
3:17 pm
Club President
April 2, 2003
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So far replacement of the camshaft has been identified. Not sure how or why it failed.
Kathleen and Brad
4:18 pm
Club Member
July 14, 2016
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BKGM Jeepers said
So far replacement of the camshaft has been identified. Not sure how or why it failed.
Under warranty I assume?
Jeff and Kathy Root
6:14 pm
Club Member
March 3, 2015
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Any kind of cam wear I would push for a engine replacement. Metal will be throughout the engine.
11:10 am
Club Trailmaster
March 13, 2015
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Looks like you already figured out the issue but the latest 3.6 have known passenger side cam issue caused by a rocker arm on the last arm at the firewall (furthest away from the oil pump). Known and common while still under warranty so dealers are very familiar with the repair. There was even a shortage of passenger side cams for a while. Specifically, the root cause is likely casting debris in the rocker arm oil passage from a sloppy supplier and the thin 0w-20 oil doesn't have the pressure to push out any debris. Annoying but overall not a huge concern as it usually shows itself under warranty period, doesn't do any damage to the rest of the engine that I am aware of, and as you found doesn't prevent you from driving home if it happens in the middle of the woods.
Over 10M of these engines on the road and this issue hits less than 1% so you got unlucky. Switching to 5w-30 in warm weather isn't a terrible idea but not necessary unless you are flogging on the engine.
7:18 am
Club President
April 2, 2003
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Jeff_R said
BKGM Jeepers said
So far replacement of the camshaft has been identified. Not sure how or why it failed.
Under warranty I assume?
Yes. This work and the broken rear window glass frame replaced 1 week ago are covered.
Kathleen and Brad
7:18 am
Club President
April 2, 2003
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70dustpan said
Any kind of cam wear I would push for a engine replacement. Metal will be throughout the engine.
That's a good point. I will look into it.
Kathleen and Brad
7:20 am
Club President
April 2, 2003
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kris_olof said
Looks like you already figured out the issue but the latest 3.6 have known passenger side cam issue caused by a rocker arm on the last arm at the firewall (furthest away from the oil pump). Known and common while still under warranty so dealers are very familiar with the repair. There was even a shortage of passenger side cams for a while. Specifically, the root cause is likely casting debris in the rocker arm oil passage from a sloppy supplier and the thin 0w-20 oil doesn't have the pressure to push out any debris. Annoying but overall not a huge concern as it usually shows itself under warranty period, doesn't do any damage to the rest of the engine that I am aware of, and as you found doesn't prevent you from driving home if it happens in the middle of the woods.
Over 10M of these engines on the road and this issue hits less than 1% so you got unlucky. Switching to 5w-30 in warm weather isn't a terrible idea but not necessary unless you are flogging on the engine.
If the casting issue may be the root cause, will the service to replace the cam also correct that oil flow problem, or could it happen again?
Kathleen and Brad
4:57 pm
Club Trailmaster
March 13, 2015
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BKGM Jeepers said
If the casting issue may be the root cause, will the service to replace the cam also correct that oil flow problem, or could it happen again?
If the new cam has similar debris in it that aren't cleaned out prior to install, yes it can happen again. Haven't heard of any repeat failures though. Just note the mileage before and after the repair. Some dealers like to list the mileage is 500 greater than at the time of the work so they can potentially double dip on warranty payout. (Jeep assumes that any failure within 500 miles of a repair is a bad job and wont pay the dealer for the re-work).
5:26 pm
Club Member
December 14, 2018
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kris_olof said
BKGM Jeepers said
If the casting issue may be the root cause, will the service to replace the cam also correct that oil flow problem, or could it happen again?
If the new cam has similar debris in it that aren't cleaned out prior to install, yes it can happen again. Haven't heard of any repeat failures though. Just note the mileage before and after the repair. Some dealers like to list the mileage is 500 greater than at the time of the work so they can potentially double dip on warranty payout. (Jeep assumes that any failure within 500 miles of a repair is a bad job and wont pay the dealer for the re-work).
Wouldn't that mean the dealer would list the mileage 500 LESS than time of work. That way after driving 1 mile you'd be at 501 and outside the 500 mile "quality repair" window.
4:54 pm
Club Trailmaster
March 13, 2015
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Sloguy said
Wouldn't that mean the dealer would list the mileage 500 LESS than time of work. That way after driving 1 mile you'd be at 501 and outside the 500 mile "quality repair" window.
You would think but the computer system logs the mileage when it comes in. They cant fool that number but they can fool the "mileage since work performed" which tracks if they get paid from the warranty fund or not.
4:08 pm
Club Member
December 14, 2018
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Sneaky.....
9:48 am
Club President
April 2, 2003
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Ok. Got the jeep back. Problem and location of the problem are EXACTLY as Kris stated!!
Received a new Cam, and several other parts. This replacement Cam is a different part number so they re-flashed the ECU to recognize the new part number.
Yes, the passenger side cam is still in short supply they had to get it from another dealerships parts inventory, or it would have been a 6 week wait.
Yes, I have documentation stating they found metal in the engine and did another oil change. I will wait 2,000 miles, and take it to my Midas for another oil change and ask them to specifically note if they find any metal shavings in the oil. - and note it in writing for me. Then I will contact Jeep and open a case for a motor warranty extension.
Thank you everyone for the input. The total price of this work actually surprised me. I paid zero under warranty but did see the work/labor cost. Total was under 3K. I didn't expect it to be so cheap.
Kathleen and Brad
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