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Author Topic: GMC Sierra 5.3 V8 engine noise.. need diagnosis.  (Read 4818 times)

Offline Ryan11405

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GMC Sierra 5.3 V8 engine noise.. need diagnosis.
« on: April 07, 2011, 11:48:55 AM »
I am seeking some help with my 2004 GMC Sierra 5. 3L V-8: I have 146,000 miles.

My truck, when started cold, makes the typical clicking noise on startup and goes away after 30 seconds-1 minute.  No problem.

The real problem is that after 5 minutes of driving (starting with a cold engine), my engine sounds like a diesel.  It sounds like it has NO oil in it! But it does have oil.

The only solution is to pull over off the road, turn it off, wait a minute, then crank it up, and drive slowly until the noise goes away.  After that, my truck sounds normal.

I have no noises whatsoever while driving. .  until after the engine cools down and then it will repeat the same diesel engine noise 5 minutes after cranking up.

The oil pressure stays a constant 40 psi from the time I crank it up cold, until it makes the diesel engine noise.  When I stop on the side of the road and sit for a minute, and recrank it, it will increase to normal operating pressure (60-65psi) when the noise stops.

What is going on, and how do I fix it? Here's a truck on youtube with the same noise as mine. .  Not my truck, but very similar noise.  any ideas?

hxxp: www. youtube. com/watch?v=AVbhvKd8ZYc

Offline billr

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Re: GMC Sierra 5.3 V8 engine noise.. need diagnosis.
« Reply #1 on: April 07, 2011, 12:30:39 PM »
What is the oil pressure when it is making the "diesel noise"?  If it is zero (or near) at that time, stop driving it; the engine bearings are probably suffering, maybe already ruined. 

Offline Ryan11405

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Re: GMC Sierra 5.3 V8 engine noise.. need diagnosis.
« Reply #2 on: April 07, 2011, 12:46:11 PM »
The oil pressure is constant at 40psi when making the diesel noise.  I've been told that there might be some sticky lifters or something gunked up in the valve train.  I stop it when it makes that noise, turn it off, crank it up, and start driving slowly and the noise goes away after a minute or so.  At that time, oil pressure increases to normal operating pressures (around 60psi). 

Offline kev2

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Re: GMC Sierra 5.3 V8 engine noise.. need diagnosis.
« Reply #3 on: April 07, 2011, 12:51:58 PM »
lets do simple things first  
is the ck eng lt on?
vehicle is STOCK?
check for fuel in oil, thinking is a leaking injector could cause the rattle,  a fuel leak down test would help.
Also coolant-  anything you see, color off, loosing fluid?  

next lets try to isolate the noise -  which cylinder - top of eng, lower part of eng....exhaust...
only happens on a COLD engine?  listen for a piston rattle AKA piston slap

If nothing above helps ID the issue,
maybe a problem with lifter- but would likely set a code,  to give you something to try add 1qt 'risoline'* to oil...

*risoline- widely available detergent for helping clean up some sludge issues

Offline Ryan11405

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Re: GMC Sierra 5.3 V8 engine noise.. need diagnosis.
« Reply #4 on: April 07, 2011, 01:03:43 PM »
kev2:

no Check engine light.  Vehicle has k&n intake, magnaflow exhaust, and hypertech tuning.  I've had these mods the whole time I've had the truck and I've had no problems until about 4-5 months ago. 

How can I check for fuel in the oil? Coolant looks normal, doesn't seem to be losing fluid. 

The noise comes from the top of the engine, on both sides.  when driving, it almost sounds like it's misfiring/not firing at all (judging from the sound of exhaust, from an exhaust standpoint). 

Only happens on a cold engine.  Once it warms up it doesn't make the noise.  I drove 6 hours straight with no noise a few weeks ago (after it stopped from driving it the first 10 minutes of course). 

It doesn't sound like piston slap in my opinion.  I've been recommended on another forum that it's a sticky lifter and I think I'm gonna try Marvel Mystery oil or some seafoam in the oil to clean it out.  Would that work compared to risoline? I'll change the oil after 30 minutes of idling after adding the seafoam of course. 

Offline nickb2

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Re: GMC Sierra 5.3 V8 engine noise.. need diagnosis.
« Reply #5 on: April 07, 2011, 03:02:07 PM »
Was there any coolant in the oil or oil in the coolant? Ever? This may be the initial cause of your problem. Did the intake ever leak on this and maybe some coolant got down into pan and washed your crank bearings, hence the knock.
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Offline kev2

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Re: GMC Sierra 5.3 V8 engine noise.. need diagnosis.
« Reply #6 on: April 07, 2011, 03:02:36 PM »
    fuel in oil -  observe level and just smell dipstick.
    A fuel pressure gauge could be used to check for leakdown.
    Risoline is my standby- no need to remove until next change interval-  

      I have to ask-  does the CEL come on at engine start then go out after @3seconds?
I am NOT a fan of K&N or chips as they complicate troubleshooting...  especially without a scanner.

    keeping with simple thing first.....
have you cleaned MAF?
try the oil detergent- your choice.
basic testing would be - fuel pressure need a gauge, engine vacuum cking for leaks,
spark plugs (AC Delco) their condition black tan dry wet?      


    

Offline nickb2

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Re: GMC Sierra 5.3 V8 engine noise.. need diagnosis.
« Reply #7 on: April 07, 2011, 03:07:32 PM »
After thought, flex plate cracked, have seen many of those on GM v8's.
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Offline Ryan11405

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Re: GMC Sierra 5.3 V8 engine noise.. need diagnosis.
« Reply #8 on: April 07, 2011, 04:09:21 PM »
nickb: I do believe there was coolant in the oil at one point.  I had problems with my coolant system and had the water pump gasket replaced a while back, along with basically the entire radiator/hoses replaced due to a cracked radiator.  They changed the oil when this was all done too. 

What is the fix for this?

I opened the oil cap and I saw smoke after driving for a few minutes.  I didn't have the noise like I normally do.  not sure why. 

What is the flex plate? and how do I see if it's cracked?

kev2: I didn't smell fuel in the oil and it's full of oil.  I don't get a CEL at all when I crank it up.  I haven't cleaned the MAF, how would I do that? I will add seafoam tomorrow and see what that does.  I don't have a fuel pressure gauge or a way to check engine vaccum.  Spark plugs are the original ones on the engine.  I have no way to remove them right now. 


Offline nickb2

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Re: GMC Sierra 5.3 V8 engine noise.. need diagnosis.
« Reply #9 on: April 07, 2011, 05:39:18 PM »
Problem with coolant in oil, is that if you ran it with enough coolant in there for a long period of time, there is no fix for it except for an engine overhaul. The flex plate can be checked depending on which transmission your have, by either a access hole at bottom of bell housing or be removing the starter and peering in the hole through there. It is hard to see if the flywheel is cracked, but when it is making this noise, you can listen to it from beneath the vehicle. The noise may be amplified by the bell housing. If you have a access hole at bottom of bell housing, remove the plate and try to see of you can hear it through there. The convertor tend to cover section where the flex plate bolts to crank, that is where they crack and knock about.

Try buying a stethoscope for mechanics, a long thin shank screwdriver or vacuum hose can work also to listen to engine noise, by pressing extremity to a point on engine and other end in your ear. Walk around engine with the tool to your ear, try to hear a difference in loudness at different points to see if it may be the cam or crank or piston slap.

Piston slap would account for good oil pressure. If it was a crank bearing, I would suspect a low pressure reading when oil is warm and engine knocking like it is. A lifter discharging would account for noise also, hard to diagnose by internet. I saw that you think it may be misfiring when it makes the noise, try determining if there is an actual misfire, such as spark cutting out or a bad injector/fuel pressure.
No CEL light is not good at start up. You should the light coming on for three seconds or so then going out. This should be repaired if the light is burnt or the ECU check engine light is faulty.

I would suspect the flex plate to make noise always so this is just an idea, not really something I would investigate unless all else fails.
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Offline kev2

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Re: GMC Sierra 5.3 V8 engine noise.. need diagnosis.
« Reply #10 on: April 07, 2011, 05:46:37 PM »
seams to  be some confusion on the CEL.. let put issue to a test, try this its easy and free autozone and other parts stores will check the system for codes- try it and write down any and all codes they mention and post them.

Offline Ryan11405

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Re: GMC Sierra 5.3 V8 engine noise.. need diagnosis.
« Reply #11 on: April 08, 2011, 05:56:48 PM »
Update: Today I put seafoam in the engine oil.  It shuddered for a little while before it got mixed with the oil.  I ran it for about an hour and a half around town and a little on the highway, to get it nice and mixed up.  I must admit, my engine ran quieter and I heard absolutely NO noise from my engine/lifters while the seafoam was in it.  I changed the oil, and for only having 1000 miles on the oil, it was nasty.  When draining, I could see sludge particles draining.  Refilled with new oil (high mileage blend) and a new filter.  I will see what noises come up in the coming days and update you on the noise.  So far, I have heard no more lifter noise.  I checked youtube and found a video with a sticky lifter and I assume that is the noise I had in question.  Thanks for all the help. 

Offline Ryan11405

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Re: GMC Sierra 5.3 V8 engine noise.. need diagnosis.
« Reply #12 on: April 10, 2011, 11:59:05 PM »
Noise is back with a vengeance. .  Taking it to a repair shop soon.  Sounds like the engine isn't getting oil at all.  whole engine is making racket. 

Offline metricwrench

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Re: GMC Sierra 5.3 V8 engine noise.. need diagnosis.
« Reply #13 on: April 11, 2011, 07:06:22 AM »
Could be a sludge engine & the pickup screen partly plugged, check the crank end play, use a large screwdriver to pry the damper forward & rearward & watch for play, should be not more then 0.020" twenty thousand of an inch.  If you can notice play by sight, the counter weight on the crank may hit the block because of worn trust bearing.
   wrench

Offline NickD

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Re: GMC Sierra 5.3 V8 engine noise.. need diagnosis.
« Reply #14 on: April 13, 2011, 06:32:30 AM »
A lot of this GM stuff uses that same 2 psi oil pressure switch in series with a resistor to the oil pressure meter.  No different than those crazy low oil warning lights.  If you really want to know your oil pressure, have to unscrew that sensor and put in a real gauge to know what your pressure is.  Don't have to tell you its a PITA, but the only way to check it.

Never did learn who determined 2 psi of oil pressure is sufficient.

 

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