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Engine knock?

Tiny
STUBBORNLY
  • MEMBER
  • 1999 DODGE RAM
  • 8.0L
  • V10
  • 4WD
  • AUTOMATIC
  • 100,000 MILES
Engine knocks under power up and start up then stops.
Knocks between power and slowing down.
New oil pump.
Friday, August 4th, 2023 AT 7:23 PM

12 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,205 POSTS
Hi,

When you hear it, is there anything as far as throttle pressure that can change it or stop it from knocking? At 100,000, there shouldn't be bearing issues unless it has had a hard life, or the oil wasn't changed on a regular basis. Also, are you using the correct oil weight?

Now, I did a little research on this and found a technical service bulletin (TSB) related to a knocking noise that is misdiagnosed as an engine knock. Instead of the engine, the Duty Cycle EVAP Canister Purge Solenoid bracket makes a knocking sound.

Take a look through the TSB below. The last pic I attached is the part's location.

Let me know what you find.

Joe

See pics below.
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Friday, August 4th, 2023 AT 10:48 PM
Tiny
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Yes, sir knocks during throttle up and throttle down z as and at start up.
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Saturday, August 5th, 2023 AT 11:07 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,205 POSTS
Hi,

Were you able to review the technical service bulletin I attached above to confirm that this isn't the issue? Also, is it loud enough to record and upload for me to hear?

Take a look through this link and let me know if it helps at all:

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

Let me know.

Joe
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Saturday, August 5th, 2023 AT 11:30 PM
Tiny
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  • 7 POSTS
Yes, I couldn’t find anything noticeable.
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Sunday, August 6th, 2023 AT 6:51 PM
Tiny
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  • MEMBER
  • 7 POSTS
Ignore the thumps at first building fuel pressure. In-line check valve is stuck open.
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Sunday, August 6th, 2023 AT 6:58 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,205 POSTS
Hi,

Yep, I heard it. It sounds like a rod knock but that is a guess. By the end of the video, it seemed like it was getting quieter. Is that the case?

Also, can you tell if the sound is louder on one side or the other or top or bottom of the engine?

Joe
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Sunday, August 6th, 2023 AT 9:40 PM
Tiny
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  • 7 POSTS
Yes, it gets quiet as it warms up. If conditions are right, you can hear a slight tic when hot. It barely. If you really get into the throttle hard the noise gets loud. And you get completely off the throttle it knocks again.
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Monday, August 7th, 2023 AT 5:27 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,205 POSTS
Hi,

Not being there makes it hard for me to tell for sure, but it does sound like a rod.

Why does it make the noise before starting? You indicated it is building fuel pressure. In 40 years of working on these vehicles, I've never heard such a thing. Are you sure we aren't getting fuel into the engine oil due to a fuel pressure issue? That could thin the oil.

Also, I don't know what the temperatures are where you are located, but what oil weight are you using? See pic below.

Let me know.

Joe
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Monday, August 7th, 2023 AT 1:38 PM
Tiny
STUBBORNLY
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The distance definitely complicates things.
The noise before starting is fuel pressure building If I bump the starter three times it will build good fuel pressure and push any air out then it starts easy. The fuel in-line check valve is stuck open and will not hold fuel rail pressure.

I’m in western Oklahoma.
Temperature doesn’t change the noise.
I’ve always used Rotella 15-40 in my engines. Had good luck so far. This started a little while after the oil pressure sensor broke off going down interstate and lost all the oil.

I’m thinking wrist pen?
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Monday, August 7th, 2023 AT 4:04 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,205 POSTS
Hi,

I didn't know that happened. It could be a wrist pin, connecting rod, or main. The only way to be sure is to take things apart.

Let me know the direction you want to go, and I will do all I can to help.

Take care,

Joe
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Monday, August 7th, 2023 AT 11:03 PM
Tiny
STUBBORNLY
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  • 7 POSTS
Lost all of the oil about a year and half ago.
Glad you offered.
I could use the help pulling it.
I really want to drop a diesel in but I'm unable to find one.

Thanks for the help. I will keep you updated.
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Tuesday, August 8th, 2023 AT 5:35 PM
Tiny
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  • MECHANIC
  • 108,205 POSTS
Hi,

If you plan to remove it, I attached the directions below. Normally, the manual provides pics to go along with the directions, but for some reason, they didn't on this engine.

Take a look through them and let me know if they help. Also, when you lift the engine, don't attach the lift to the intake. The engine is too heavy and will cause damage.

Let me know,

Joe

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Tuesday, August 8th, 2023 AT 9:17 PM

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