Engine making a knocking sound

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Apr 6, 2011 | 01:22 PM

jt371

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From: Upstate NY

Engine making a knocking sound

I noticed about a month ago that at an idle when the engine was warm it had a knock coming from the passenger side. It is there when it is cold just not as bad as when warm. Also sometimes when it is warming up the sound will some and go. I have retorqued passenger side rockers and injectors. Looked over push rods also,they looked ok. Started with valve cover removed and didn't hear it from the top side of the motor, oil looked the same coming from all the injectors. Installed FRx, didn't help the noise. Have ran scan tool and found that #8 would trip on cyl contribution test. Installed black IH CPS now the #8 doesn't trip anymore. No codes come up for any of the tests I can do. (Snap-on MT-2500) Still knocking at idle. Changed the engine oil and filter. Used Rotella 15w40 and Motorcraft filter. Made an injector breakout box. Tested it, by turning off the injectors one at a time, none of them eliminated the knock. #5 changed it a little. Have tested the lpop it was 42 lbs at an idle when cold. Haven't had a chance to test it when warm. I checked it at the hpop reservoir where the oil pressure sensor is. Should I check it by the engine oil filter? Have been monitering ICP with scan tool. It is over 900psi at an idle at first startup. It is about 450-475psi when warm at idle.I have removed the fan belt and started, didn't get rid of it. Removed the inspection cover for trans, started truck, noise not coming from trans. I have got it up to highway speed and let off the throttle. There is a slight knock sound but it had done that ever since I have had it. It has been almost 3 yrs now. But never had this idle knock before. I know I may have something mechanical wrong inside the engine but am trying to eliminate anything that can be checked without pulling the engine.
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Is there anything else I should be looking at?

Thank you.<O

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Apr 6, 2011 | 02:25 PM

woodnthings

Cargo Master

Joined: May 2010

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From: Snohomish, WA

With it quitting when you killed #5, I would pull that cylinders rockers and make sure the pushrods are ok. I had a friend with a similar issue and it was fixed when he pulled the rockers and inspected the valve train out. Only thing we could figure is something was stuck in the pushrods and it was loosened up when taken apart. With a mechanics ear can you verify it is in the head area?

Apr 11, 2011 | 05:43 AM

jt371

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From: Upstate NY

I had a chance the other day and checked the low oil pressure at an idle when warm, 22psi. Going to look it over more tomorrow it all goes well.

Apr 11, 2011 | 05:56 AM

Kwikkordead

Fleet Owner

Joined: Jun 2004

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From: Rio Rico, AZ.

You've pretty much covered it.
I ended up replacing my engine to get rid of the same kind of knock.

Apr 11, 2011 | 10:51 AM

jt371

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From: Upstate NY

Dan, That is the hard truth, which I have a bad feeling you are correct.

Apr 13, 2011 | 05:20 AM

jt371

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From: Upstate NY

Quote:

Originally Posted by woodnthings

Removed, inspected all the rocker arms and pushrods, and retorqued. Still knock. I have a feeling that it is a bad bearing. But I figured I would give it a shot.
I sent out a oil sample and came back with higher concent ration of lead. Which they say comes from bearings.
Checked fuel pressure also. Gauge would peg at 100psi and keep going. So loosened up the FRx and found that the spring was caught on one of the little tabs. Recentered spring and reinstalled. Now 60psi. I had been driving around for 2 weeks with over 100psi of fuel pressure. Glad it did blow the hose or start leaking somewhere.

May 15, 2011 | 09:03 AM

jt371

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From: Upstate NY

The other day I was looking over my truck in regards to this knocking. I was underneath it with it running and just happened to put my hand over the CCV. I realized that when I removed my hand the crankcase was getting pressurized.

So I have now parked it until I get the time to do more work on it. I'm buying a house and funds are going to be limited soon, just waiting on the closing. On the plus side the house comes with a huge shop.