Yeah, Captain Hooks nightmare ... Tic Toc Tic Toc

Tom G · April 25, 2017

If it is a lifter, what kind of lifters should I get for a 05 GMC 2500 HD with a 6.0 vortec?

This video shows whats goin on.

More to come as the information becomes available.

Formulabruce · April 25, 2017

This engine has a bent pushrod most likely. Over rev can cause it. need to check them, spin and see if any others are touching head while you are in there .

dewfpo · April 25, 2017

Did the noise come on all of a sudden or did it gradually get louder and louder?

Is the engine still running smooth?

Any Codes?

My first thought was, it doesn't sound like a lifter. If you could use a stethoscope, that would nail the area down. If it's coming from a valve cover, it could be a bent push rod, collapsed lifter or even a broken rocker arm.

DEWFPO

Tom G · April 26, 2017

All pressures are good, no loss of power, no other issues at all.

Parked it around noon runnning well. When I started it at 3 that same day the noise was there loud and clear and has not changed for about 3 weeks.

dewfpo · April 26, 2017

This is going to sound odd, but I had a similar situation occur with my Toyota FJ 4.0L V-6 but the noise wasn't quite as loud as yours but still very noticeable. No noise, then noise, but only when the engine was cold. It turned out to be the hydraulic tensioner on the timing chain. The noise eventually went away on it's own. That's why a stethoscope is a excellent idea to isolate the noise. There are a lot of moving parts in engine.

DEWFPO

Tom G · April 26, 2017

I already ran for 120 miles with a quart and 3/4 of tranny fluid, and then changed that oil and it had not made a difference. Im gonna put some MMO through it today and see if that does not make a difference. If not, Ill go inside and see what I can find. The garage diagnosed it as a push rod as well. But then another inspector diagnosed it as a connecting rod. Wouldnt the noise be coming from way down low if it were a connecting rod? The noise does not come and go.

Dnt · April 26, 2017

That noise will for sure give you a sick feeling in the pit of your stomach......... First thing that I would do would be to pull the serpentine belt just to make sure I do not have a belt tensioner / AC compressor /alternator etc mimicking a push rod click.

Tom G · April 26, 2017

Tomorrow I will be checking the push rods to see if one of them is bent.

I am betting since I was running on 5/6 the amount of oil needed that one of the bearings is going. Gone I guess I should say.

Ill update you guys on what happens with the ol' push rods.

Tom G · April 27, 2017

This is going to sound odd, but I had a similar situation occur with my Toyota FJ 4.0L V-6 but the noise wasn't quite as loud as yours but still very noticeable. No noise, then noise, but only when the engine was cold. It turned out to be the hydraulic tensioner on the timing chain. The noise eventually went away on it's own. That's why a stethoscope is a excellent idea to isolate the noise. There are a lot of moving parts in engine.

DEWFPO

I think I'll have to use a hose. Ill let you know what I hear. The cold temperatures caused it to come and go your saying?

dewfpo · April 27, 2017

I think I'll have to use a hose. Ill let you know what I hear. The cold temperatures caused it to come and go your saying?

A hose will work also, I've don't that when I didn't have a stethoscope available. It only made noise on cold startups but them quieted down after the engine warmed up. The noise lasted for about 4 months and gradually got quieter and quieter until it went away.

DEWFPO

Tom G · April 27, 2017

This engine has a bent pushrod most likely. Over rev can cause it. need to check them, spin and see if any others are touching head while you are in there .

I have never seen them so straight and so clean. The rocker arms are good and solid and all the push rods are a ok. Now I am trying to track down the specs for the rocker arm bolts and cover for the valves. Lookin like a spun bearing.

davester · April 28, 2017

Did you check the lifters? I would check those, because that video you posted didn't sound like a spun bearing. I would expect a bearing to be more constant scraping. If not the lifters, then maybe a problem with a lobe on the cam.

Tom G · April 28, 2017

Did you check the lifters? I would check those, because that video you posted didn't sound like a spun bearing. I would expect a bearing to be more constant

scraping. If not the lifters, then maybe a problem with a lobe on the cam.

I went in and checked the push rods on one side today.... all clear. Everything was good and clean in there too. I went ahead and sprayed some carb cleaner into the holes to get to the lifters. The rocker arms were all completely solid. no play at all.

I could be wrong but a spun bearing gives the connecting rod enough play to tap on its downstroke. The scrape noise is not really heard.

Tomorrow I am going to do the same check on the other cylinders on the other side too. If it is still tapping I may need some help figuring out how to get to the connecting rod's bearings and how to figure out which cylinders bearing needs to be replaced.

davester · April 28, 2017

If a bearing has spun, it's not just a "replace the bearing" job. You also likely have to replace what it goes into.

IE, replace the rod, and then possibly also machine/replace the crankshaft.

And you want to figure out why it spun, it happened because something went wrong (like, say, it stopped getting oil).

sdeeter19555 · April 28, 2017

If a bearing has spun, it's not just a "replace the bearing" job. You also likely have to replace what it goes into.

IE, replace the rod, and then possibly also machine/replace the crankshaft.

And you want to figure out why it spun, it happened because something went wrong (like, say, it stopped getting oil).

Depends on the end use...if you want longevity and value, full rebuild; if you want to get a few miles out of it before it's scrap, emory cloth and a new bearing.

I've done that more than once (not that I'm proud of, but it got me or a friend by for a spell), I have even pulled a rod and piston from a cylinder with a hole through the block and ran that engine on five cylinders for a long time...I think that dozer is still going to this day.

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