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Have a noise in engine. Sounds the loudest at the valve cover, but removed it and saw nothing. Listened on the block barely hear it, oil pan barely hear it, X-mission inspection cover barely hear it. But on top the rear right valve cover it very loud(using doctor type stethoscope from Kragens) any ideas its a 98 Chevy 3500HD 7.4L. Trying to insert short video but it not working?
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Sound like a lifter to me…
Remove the fuel pump when the engine is running so the engine dies… remove the valve cover and have somebody crank the engine as you look at the valve… crank it for a good while and i would be surprise if you will find 1 rocker barely moving compare to the other one. I don’t know if you feel a misfire at idle…. but if so…. you should be able to tell right away once the engine crank for a good 5 seconds.
The camshaft might be damaged from the spring kicking back the pushrod/lifter back on the cam.
What happen is the lifter doesn’t hold pressure so all you hear the slack being removed as the cam lobe apply pressure on the lifter to then go up…. you may have slight or no movement…
Get that taken care soon as it may end up being costly
K
Will do that now but as a side note engine idles great no detectable miss good oil pressure(according to dash gauge).Forgot about the hydro-lifters maybe stuck might try dump some Marvel Mystery in it.
well here is a video of the rockers they all look fine to me and also no noise when just cranking engine.http://youtu.be/tS8qFJvp3uQ
If your valve cover is still out. squeeze a piece of cardboard on the bottom part of the head so the oil will not splash all over the head… then start the engine… you will be able to point which one is the bad guy.
Look for the oil squirting out. You should be able to see a flow difference.
To clean a sticking lifter, you need to disassemble the faulty one. Inspect the pushrod by looking through the hole for clogging. Then use a good carb cleaner and go clean the top of the lifter as it is the only thing you can do at this point (lifting the intake will get you access to the lifter).
You can try…. to drop the oil and filter… and then refill with 2 liter of transmission fluid (try to fill the new filter as much as you can with ATF) and top it up with the oil you usually take and drive it for couple of day… The oil might take dissolve the crap in the lifter.
It is actually really noisy so I don’t know if the second recommendation would work… but if you can pinpoint which of that bank is causing the noise you will be half way there
Good luck
Ya I think the back 3 were not oiling well at first put 1/2 tranny fluid and 2 of freed up some but back one and I think some on otherside still jammed up. Had to cut video short because I think I started to here some sqeeling from cam bearings.Funny thing for about 3-5 seconds the noise actully went away but came right back 🙁
You should be able to put you hand on it or a screwdriver and feel which one is the noisy one at it sound to be only 1 making the noise. I would compare them 1 by 1. It sound you had a pulley or something else making noise at the end of your video as well.. Am I right???
Once you figure which one is the one …. if you attempt to remove the rocker arm for inspection. Make sure you know the procedure and you are comfortable to put it back together as their is an adjustment procedure.
Hopefully it is just clogged up. What is the mileage and i that noise came out of nowhere or it gradually got worst?
That noise was starting to get worse and it only started after I put in the tranny fluid, I am almost positive it was a cam bearing starting to squeal. I am already gonna order a cam, lifters, and new push rods for it I guess going to be replacing cam bearings also. I guess going to finally have to break down and buy a cam bearing installer :unsure:
Also it is owned by a concrete company and they tell me that even tho it has only 70K miles on it that they use it to park at job sites and run it for A/C and heat for the workers so it has allot of hours on itSounds like you have a plan based on your posts. To be honest, I’m not sure if there’s more that I can add. Tracking down noise like this is sometimes a guessing game. I think you’re on the right track however because it does sound like top end to me. Keep us posted on how things go after the cam and lifters. Perhaps during the process of tear down you’ll find something significant. Keep us updated.
You have a spun rod bearing my friend. Time to remove the oil pan and inspect. The squealing noise you hear is the bearing spinning inside the connecting rod. You will probably see a connecting rod that is darker than the rest.
[quote=”wysetech” post=94494]You have a spun rod bearing my friend. Time to remove the oil pan and inspect. The squealing noise you hear is the bearing spinning inside the connecting rod. You will probably see a connecting rod that is darker than the rest.[/quote]
SSSHHHHHH!!!!!
In the back of my head I know I have heard sqeeks like that before but I am trying not to think that at the moment…lolAlso when trying to look up parts prices I decided to run the VIN and check door sticker(being that emission one is MIA) door says 09/97 but VIN look up returns as 96. So with out tearing it down I can’t confirm whether it a flat or roller positively. Which means have to draw up 2 est. which I hate doing because makes me look like I am unsure. Which technically I am but I hate when the customer see’s it that
way….lolBut hey even medical doctors have to do exploratory surgery sometimes to get a better idea of what is needed and they spend allot more years in school then I did.
Just thought I would post a update to this issue. Been sidetracked on some other jobs so finally got caught up enough to get back on this one.
So far I have pulled upper/lower intakes, lifter retainer plate, lifter guides, and drivers side lifters(doing pass side tomorrow). What I have found so far is 5 were so stiff I couldn’t even depress the plunger at all(using the tip of my finger), and 3 I could depress the plunger maybe a 1/16″-1/32″(just enough to relieve the pressure on the plungers retaining clip). So I disassembled all the lifters drivers side down to the check ball and spring cleaned and re-assembled, then placed them in a can full of fresh oil and using a push rod put pressure on the the plunger till I could see no more air bubbles come from the oil hole on the lifter. Also checked each of the rollers them self to make sure they a rolled smoothly. Looked at the cam lobes and didn’t see anything that jumped out at me, just normal wear. So I put assembly lube on rollers and all contact surfaces and put it back together except for the valve lash(“Net-Valve Lash” the book calls it). A little confused there, it has rocker arm studs with a ball and sleeve that go thru the rocker arm and a nut on top. Now 1 book says torque to 40 ft-lb another says 45 ft-lb. But when I reach these values I can see my valve spring is being depressed to opening when it should not be opened. So not really understanding the purpose of the sleeves since they don’t stop you from over adjusting the lash. I would think the sleeve should bottom out on the studs and torque would be on them keeping you from applying to much pressure on the rocker balls. But gonna investigate that more tomorrow and get the passengers side done(I hope).
More update to follow- Same bat-channel, same bat-time.lol Little reveal of my age there.Yes you are probably correct, but being that it is a GEN VI 7.4L(454ci) Vortec which are a little bit pricey. The few hours labor with the possibility of getting a few more miles out of it, doesn’t seam to far out there. You have to keep hope alive…lol
Now back here in reality, after rebuilding all the lifters 3 out of 16 now show great oil delivery at the rockers. But the rest still just seep oil out at the rockers even tho it has 60PSI of pressure. And it is not a plugged galley, because 2intake 6exhaust and 3exhaust are the one’s with great flow now. So they are kind of spread out. So back to the drawing board.Try running a quart of automatic transmission fluid in place of a quart of oil during each oil change. That stuff works pretty good at freeing up lifters and cleaning gunk form oil passages.
Good luck and keep us posted.
Yes tried that and that when it started making that awful sq-eek that makes all mechanics cringe because it sounds like a spun bearing. So after about 10-15 minutes of letting it idle while I was hiding from the knocking and sqeeking noise in the office. I drained that oil/Xrans mixture and replaced with fresh oil and about 16oz of good ole’ Marvels. But before I could run that thru it I took the lifters out and rebuilt them. So when time allows again will see what happens with that concoction. By the way Eric whats your spin on “Marvel’s Mystery Oil”? I love that stuff use it everywhere(except the bedroom, even tho it has a fresh minty smell…lol). Use it daily in air tools ,in fuel, in oil,and ect….That stuff and “Lucas” have come to my assistance many times over the years.
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