I was told by a mechanic of 30+ years to give that a try. Its alot easier than removing the trans and t-case to check. And yes i use 87 octane
Knocking noise at idle
- Thread starter Zx2ner88
- Start date
New update on the situation. I finally got around to removing the TC bolts and ran the engine. The noise was gone with the engine not connected to the torque converter. I put 1 washer in between each mounting pad and the noise is much less pronounced now, but still present. I didnt hear anything while spinning the TC by hand either so im thinking there is a crack on the flexplate somewhere near the crankshaft mounting bolts. Can anyone recomend a good source for a flexplate?
gmcman said:
I hadn't considered this. Might do my oil change a little early just to check for any metal.
I'll try to get another clip. The noise is exactly the same whether in gear or not, temp has no effect. The only change is when the engine is revved up, where it seems to dissipate after about 1500 rpm
Sorry if I missed it but you did remove the serpentine belt to rule out the water pump? Just checking.
Zx2ner88 said:
And you removed the primary coil lead for each coil to see if the noise isn't rod related? This test removes the combustion pressures on the piston. If it is rod related the noise should abate.
Zx2ner88 said:
So it's not rod related. And highly unlikely crank related. And from my understanding one bad bearing in the crank wouldn't make so much racket as the other bearings will hold the crank true.
So it appears we have an unknown noise coming from the bottom of the crankshaft.
You know I had a similar yet fainter sound sort of like yours. It ended up being a gummed up valve adjuster.
Have you tried any flushes to see if the noise goes down? How about changing the CPAS? That could be an oil restriction as well.
Also, GM has made it known that sometimes certain aftermarket oil filters can cause such a racket. Have you been using an ACDelco PF61e filter just to rule that out?
Next step would be to check oil pressure to rule out bearing issues for sure. A bad bearing will show it's face as erratic oil pressure.
gmcman
Member
- Dec 12, 2011
- 4,673
Something else to try is with the TC attached, raise the rear wheels and let the engine idle but keep it in "D" and allow it to change gears. Listen for any changes as the transmission approaches a 1:1 ratio in 3rd. Perhaps place trans in 3rd and if the noise persists then go to 4th but just throwing this out as an idea.
Also if there was previous transmission work I would check to see if the bell housing bolts are tight all the way around.
gmcman
Member
- Dec 12, 2011
- 4,673
Zx2ner88 said:
Firing order is 1-5-3-6-2-4
Noise is coming from the rear, I know you did this test but I want you to try it again and start with pulling #6, then with #6 pulled, pull #3 as well.
Then with all the coils connected, pull #5, then with #5 pulled, pull # 1.
What you are doing is removing combustion from target cylinder, then removing combustion from previous cylinder. This keeps the crank from working the bearing in the rod as the upward force from the previous combustion has increased pressure on that target bearing. So basically during the compression stroke of target cylinder, there isn't a sharp increase in force on the compression stroke from the previous firing, even though there is upward force on the rod, this keeps it more even.
Not a tried and true method but I feel it's worth a try.
@CaptainXL-I was actually looking for a recomendation on a flush. What would be best to use for that? I will also run a delco filter at my oil change, And ill do a pressure check as soon as i can get my hands on a pressure gauge. I should be able to do the coil test you recomended by thursday
@gmcman- I have no idea if there was any transmission work done unfortunatly. I doubt it because the vehicle seems to have been very well maintained prior to me purchasing it. I will try what you said next time i have access to a lift as well
@gmcman- I have no idea if there was any transmission work done unfortunatly. I doubt it because the vehicle seems to have been very well maintained prior to me purchasing it. I will try what you said next time i have access to a lift as well
Zx2ner88 said:
I've mentioned it about 6 times. You could just do an advanced search under my name using "flush" as a keyword.
DenaliHD66
Member
- Dec 4, 2011
- 597
Got this knocking noise myself even when engine is fully warmed up. Its not the "diesel" sound. It sounds like it is coming from UNDER the engine block. The exhaust manifold was replaced so it is not that. The fan clutch has a distinct ticking noise, but there is something else knocking.
Playsinsnow
Member
- Nov 17, 2012
- 9,727
Zx2ner88 said:
Captain laid it out in this thread.
http://gmtnation.com/f25/engine-tick-knock-2005-97k-miles-7734/
Playsinsnow
Member
- Nov 17, 2012
- 9,727
CaptainXL said:Thanks Mr. Playlooking for a new truck right now. Otherwise would help more.
You put the info out, it's up to whoever to decide what suits their fancy
Unless you find a steal, I'd avoid higher mileage vehicles. Otherwise you may pay the difference one way or another.
8
Oh. Mileage doesnt scare me. I personally give each of my used car candidates a complete lobotomy. Hehe.
Now looking for a Chevy Silverado 2500 HD. Yeah, the wifewants a big trailer. Lol
If your smart and know what your looking for you can find used vehicles with rebuilt, replaced engines or trans. That 2005 Tahoe I was looking at only has 660 hours on the engine according to the D I C. Yet it has 110000 on the odo.
Playsinsnow said:You put the info out, it's up to whoever to decide what suits their fancy
Unless you find a steal, I'd avoid higher mileage vehicles. Otherwise you may pay the difference one way or another.
Oh. Mileage doesnt scare me. I personally give each of my used car candidates a complete lobotomy. Hehe.
Now looking for a Chevy Silverado 2500 HD. Yeah, the wifewants a big trailer. Lol
If your smart and know what your looking for you can find used vehicles with rebuilt, replaced engines or trans. That 2005 Tahoe I was looking at only has 660 hours on the engine according to the D I C. Yet it has 110000 on the odo.
Playsinsnow
Member
- Nov 17, 2012
- 9,727
CaptainXL said:
If I rid the wife's car, someone's getting a high miles with a rebuilt tranny with less miles than I bought it with
I don't know about the Tahoe, but I can reset my clock on the odo/DIC at anytime. And pause it. I'll go out on a limb and guess that someone never touched it. Only about a years driving, give or take some. I'd want papers that document anything... Sorry I went a little
Yep. Definitely asking for autocheck and dealer recods.. All that crap. Didnt know you could reset the engine hours meter. 
Yeah, sorry op for being off topic.
Yeah, sorry op for being off topic.