Grinding tapping noise

Tiny
MSZIPPL
  • MEMBER
  • 2007 JEEP CHEROKEE
  • 3.7L
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 108,000 MILES
When starting cold engine I hear a loud grinding tapping noise. After 30 seconds or so it dissipates. Had oil sensor replaced because it was bad. Replaced all spark plugs and oil 2 due to misfire in cylinder 2. After replacing plugs and the coil is when the noise appeared. Need help.
Friday, June 12th, 2020 AT 4:49 AM

18 Replies

Tiny
ASEMASTER6371
  • MECHANIC
  • 52,796 POSTS
Good morning,

Can you upload a video of the noise to this post so I can hear the noise? I need to hear what you hear.

Roy
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Friday, June 12th, 2020 AT 4:57 AM
Tiny
MSZIPPL
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  • 10 POSTS
I can but not until later in day after it sits for 5+ hours. Only does it when engine is cold.
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Friday, June 12th, 2020 AT 5:07 AM
Tiny
ASEMASTER6371
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Okay, sounds good.

Upload it when you can. I will be here to help.

Roy
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Friday, June 12th, 2020 AT 5:27 AM
Tiny
MSZIPPL
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Thank you.
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Friday, June 12th, 2020 AT 5:29 AM
Tiny
ASEMASTER6371
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You are welcome.

We are always glad to help.

Roy
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Friday, June 12th, 2020 AT 5:32 AM
Tiny
MSZIPPL
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This is milder than early this morning it's the like tapping noise right at the beginning.
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Friday, June 12th, 2020 AT 10:56 AM
Tiny
ASEMASTER6371
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That noise is from the lower end of the motor. There is no oil lubricating the bearings on startup.

https://www.2carpros.com/articles/engine-noises

This could be the oil pump that is draining back and the system has to prime all over again after sitting.

https://www.2carpros.com/articles/high-or-low-engine-oil-pressure

You need to get this fixed as soon as you can. Each time you start it like that, you are doing damage to the bearings.

I would have someone check the oil pressure when it is cold to verify.

Roy

REMOVAL
1. Remove the oil pan and pick-up tube.
2. Remove the timing chain cover.
3. Remove the timing chains and tensioners.
4. Remove the four bolts, primary timing chain tensioner and the oil pump.
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Friday, June 12th, 2020 AT 11:14 AM
Tiny
MSZIPPL
  • MEMBER
  • 10 POSTS
Is it possible that it is a lifter tapping?
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Friday, June 12th, 2020 AT 11:24 AM
Tiny
ASEMASTER6371
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No, that noise is too deep for a lifter.

Roy
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Friday, June 12th, 2020 AT 11:33 AM
Tiny
MSZIPPL
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Would that be associated with the oil pressure sensor that was replaced 3 days ago? But why would this noise only happen after changing spark plugs and coil?
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Friday, June 12th, 2020 AT 11:35 AM
Tiny
ASEMASTER6371
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It has nothing to do with the pressure switch. That just sends a signal to the ECM.

As far as the work, none of it is related. It would have happened even if you did not do the work.

Roy
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Friday, June 12th, 2020 AT 11:39 AM
Tiny
MSZIPPL
  • MEMBER
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Thanks.
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Friday, June 12th, 2020 AT 11:39 AM
Tiny
MSZIPPL
  • MEMBER
  • 10 POSTS
So best suggestion is to take it to Jeep dealership and let them do it?
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Friday, June 12th, 2020 AT 11:40 AM
Tiny
ASEMASTER6371
  • MECHANIC
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No, I would find an independent shop that can help you. They are cheaper by a long shot.

If you go to the dealer, they will tell you it needs a motor and send you to the showroom for a new car.

Roy
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Friday, June 12th, 2020 AT 11:58 AM
Tiny
MSZIPPL
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This is after running at a idle which is only 500 rpm's. For 10 minutes, just up and down the long driveway.
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Friday, June 12th, 2020 AT 4:26 PM
Tiny
ASEMASTER6371
  • MECHANIC
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It sounds like there is no oil at the top of the motor.

Back to the oil pump as we discussed.

Roy
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Friday, June 12th, 2020 AT 4:34 PM
Tiny
MSZIPPL
  • MEMBER
  • 10 POSTS
How hard is it to change for someone who has some knowledge around and under a car?
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Friday, June 12th, 2020 AT 4:36 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,796 POSTS
It is a huge project as it requires removal of the oil pan and the front cover of the motor.

The book pays over 8 hours in a shop for this. If you were to do it, it would about 3 times that time and maybe more as the timing chain has to be removed to gain access.

The steps below sound simple but are very involved.

I attached a YouTube video of the oil pump replacement for the 4.7 but is the same as a 3.7.

https://www.youtube.com/watch?v=AAj4DeFtZp0

https://www.youtube.com/watch?v=qfG4mgvWD5c

The second one is for the oil pan which also has to be removed as well.

Roy

REMOVAL
1. Remove the oil pan and pick-up tube.
2. Remove the timing chain cover.
3. Remove the timing chains and tensioners.
4. Remove the four bolts, primary timing chain tensioner and the oil pump.
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Friday, June 12th, 2020 AT 4:53 PM

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