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#1 |
Registered User
Join Date: Feb 2018
Location: Oroville, CA
Posts: 39
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Grinding/Screech from Block
Hey all, back once again but this time the truck is street...street...well.... uh, street-somewhat. It runs and can get from A to B. With that being said!
I have this interesting issue where there's a grinding/screeching noise, like an old belt noise coming somewhere from around the block/behind the block. I've taken the belts off to ensure it's not something that's being turned, or the belts themselves. Still screeching. I have no idea how to relate the noise to anything except possibly a loose bearing. It sounds like a wheel turning and grinding against something else? I don't have a video right now to showcase it, but imagine the noise that a loose fan with a bad bearing would make, until I can get a video. The noise does not increase with RPMs/Acceleration. The noise is constant. Gear selection does not change anything. Noise occurs in P/N/D. Engine Temp/Oil Temp doesn't affect it - Hot or Cold, noise occurs. Noise occurs immediately after startup. Noise does not exist when turning over. 1969 GMC Custom 1/2 ton Chevy 350 small block, new plugs, new belts Edelbrock Carb (1406?) - 500CFM (New) Truck drives with no noticeable issues. [EDIT] SOLVED Power brake plug in the back side of the Edelbrock was open. Once plugged, the sound stopped completely. Will be hooking the brake booster hose to it appropriately soon.
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1969 ![]() Last edited by RhapidFyre; 02-08-2019 at 10:16 PM. |
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#2 |
Senior Member
![]() Join Date: Apr 2016
Location: Cypress, TX
Posts: 3,707
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Re: Grinding/Screech from Block
Disconnect your heater or A/C blower motor electric wire and see if that's it.
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#3 | |
Registered User
Join Date: Feb 2018
Location: Oroville, CA
Posts: 39
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Re: Grinding/Screech from Block
Quote:
I'll get a video when it's daylight outside and I'm off work.
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#4 |
Senior Member
![]() Join Date: Jan 2001
Location: Orem, Utah
Posts: 7,912
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Re: Grinding/Screech from Block
Check your transmission bellhousing and torque converter bolts. I know you said it's not RPM-dependent, but still...
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I have sworn upon the altar of God, eternal hostility against every form of tyranny over the mind of man. - Thomas Jefferson |
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#5 |
Registered User
Join Date: Jan 2012
Location: St Louis Mo
Posts: 214
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Re: Grinding/Screech from Block
Check your starter. If it doesn’t disengage once the engine is started it can make a squealing noise.
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#6 |
Senior Member
![]() Join Date: Apr 2016
Location: Cypress, TX
Posts: 3,707
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Re: Grinding/Screech from Block
An electric motor with bad bearings that is not directly attached to the engine would squeal or grind but not change with engine RPMs/Acceleration, and it would also normally come on with the engine started or key on. So that would be my top suspect, a bad electric motor. The only electric motor like that on a stock truck is the blower motor. But some folks have put in accessories, such as electric fans on the radiator.
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#7 |
Senior Member
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Location: Centennial, CO
Posts: 2,949
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Re: Grinding/Screech from Block
I have had an exhaust leak make a noise like you describe. Very weird, but it had me chasing engine noises for a bit.
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ClusterTruck: 68 C10 Bought in 89, wrecked in 03. Slow low $ rebuild started '17. 6.0 & TKO http://67-72chevytrucks.com/vboard/s...d.php?t=788602 93 K1500 Short Step, 350, NV4500, EBL flash ECU. Vortec heads & roller cam someday... 05 Jeep Wrangler Unlimited. 3” lift & 6-speed 02 E320 the insurance total “free car” 13 Tahoe LTZ |
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#8 |
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Location: Mt Airy, MD
Posts: 85,859
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Re: Grinding/Screech from Block
The constant in all RPMs has me stumped, unless it's the heater motor. Just pull the fuse. There is the wiper motor, too, and that is above the back of the engine, so pull that fuse, too. How about a radio, is one in it? IIRC, they don't play while cranking, only before and after?
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"BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~ |
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#9 |
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Join Date: Apr 2011
Location: Fairview Park, Ohio
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Re: Grinding/Screech from Block
If you put the key to the on position but don't crank the engine and there is no noise then
It's not a blower motor or wipers etc. simple way to rule those items out. Take about a 36" piece of broom stick and hold it to your ear. Hold other end to starter, trans, back of engine etc. you be amazed how much you can hear. That may help you pinpoint the location. Mark
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My build page http://67-72chevytrucks.com/vboard/s...d.php?t=764662 My cabinet building site http://www.cbcabinets.com Last edited by rockyrivermark; 02-02-2019 at 11:06 AM. |
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#10 | |
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Join Date: May 2011
Location: Northern Calif.
Posts: 3,689
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Re: Grinding/Screech from Block
Quote:
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#11 |
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Location: Centennial, CO
Posts: 2,949
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Re: Grinding/Screech from Block
Or a long piece of hose. Great for exhaust leak diagnosis, you won’t hear that type of noise thru something solid.
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ClusterTruck: 68 C10 Bought in 89, wrecked in 03. Slow low $ rebuild started '17. 6.0 & TKO http://67-72chevytrucks.com/vboard/s...d.php?t=788602 93 K1500 Short Step, 350, NV4500, EBL flash ECU. Vortec heads & roller cam someday... 05 Jeep Wrangler Unlimited. 3” lift & 6-speed 02 E320 the insurance total “free car” 13 Tahoe LTZ |
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#12 |
Registered User
Join Date: Apr 2011
Location: Fairview Park, Ohio
Posts: 1,031
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Re: Grinding/Screech from Block
OP
Please post back when you figure it out. Help the next guy.
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#13 |
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Location: Mt Airy, MD
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Re: Grinding/Screech from Block
x2! And those who offered their help would like to know if they in fact did help you.
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"BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~ |
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#14 |
Registered User
Join Date: Feb 2018
Location: Oroville, CA
Posts: 39
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Re: Grinding/Screech from Block
Sorry everyone that it took so long to reply. We work 24 hours on the ambulance and I got busy.
I dropped my stethoscope into the engine, and isolated where the noise is coming from but it makes no sense - Noise is coming from the back side of the Eddy. When I lower the steth towards the block, the noise disappears. When I turn it around to the distributor, it disappears. The noise is loudest towards the bottom half of the eddy on the back side of the block. I'll read through your responses right now. [EDIT] I had the starter tested at O'Reillys, no noises or issues. Stethoscope located the noise to be the back lower half of the Eddy. No changes with the blower motor/heater.
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#15 |
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Join Date: Mar 2014
Location: Volant, Pennsylvania
Posts: 351
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Re: Grinding/Screech from Block
I know that you said it doesn't change with RPM but pull the engine oil dipstick to make sure it is not hitting the crank.
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#16 | |
Registered User
Join Date: Feb 2018
Location: Oroville, CA
Posts: 39
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Re: Grinding/Screech from Block
Quote:
VIDEO https://www.youtube.com/watch?v=nmnGATsI4ZU
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#17 |
Registered User
Join Date: Feb 2003
Location: Santa Ana, CA
Posts: 2,191
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Re: Grinding/Screech from Block
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#18 |
Who Changed This?
![]() Join Date: Jan 2013
Location: Simi Valley, CA
Posts: 10,403
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Re: Grinding/Screech from Block
Yup, that is sure what it sounds like!
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~Steven '70 Chevy 3/4T Longhorn CST 402/400/3.56 Custom Camper Simi Valley, CA |
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#19 |
Registered User
Join Date: Jul 2002
Location: St. James, MO
Posts: 1,239
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Re: Grinding/Screech from Block
Carb gaskets leaking?
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'69 Longstep K-10: 327/SM465/T-221/Closed Knuckle Dana44/12-bolt. |
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#20 |
Senior Member
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Location: Waterford California
Posts: 2,526
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Re: Grinding/Screech from Block
What the hell is an "Eddy"??
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#21 |
Registered User
Join Date: Jul 2015
Location: Sedalia Mo.
Posts: 1,131
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Re: Grinding/Screech from Block
I was thinking a little "man" named Ed, you know that special option that did not show up on the SPID...lol, I'm too funny...sorry.
Now we know, short for the carb.
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He who is without oil shall throw the first rod. Compressions 8.7:1 1972 C10 1976 C10 (parts truck) 1985 K20 |
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#22 |
Registered User
Join Date: Apr 2011
Location: Fairview Park, Ohio
Posts: 1,031
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Re: Grinding/Screech from Block
Edlebrock carb
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#23 |
Registered User
Join Date: Apr 2010
Location: So Cal
Posts: 1,437
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Re: Grinding/Screech from Block
>>the eddy on the back side of the block.<<
What's a carb doing on the back of the block. >>>... dropped my stethoscope into the engine.... When I lower the steth towards the block....When I turn it around to the distributor...<< What kind of stethoscope do you drop, lower and turn around?
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'67 GMC 2500, 292, 4spd, AC |
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#24 |
Registered User
Join Date: Jul 2015
Location: Sedalia Mo.
Posts: 1,131
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Re: Grinding/Screech from Block
Look at the video at 7 seconds and it looks like the "Eddy" is missing a plug that would normally be used for power brakes. And, again at 29 seconds. AND at 32 seconds...this one is the money shot...I don't see a plug. I hope that's it...easy fix!
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He who is without oil shall throw the first rod. Compressions 8.7:1 1972 C10 1976 C10 (parts truck) 1985 K20 |
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#25 |
Registered User
Join Date: Feb 2018
Location: Oroville, CA
Posts: 39
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Re: Grinding/Screech from Block
The noise is coming from the back of the Eddy, towards the end of the block. I can get more technical if necessary. I figured it wasn't that hard to understand.
The kind that you stick in your ears and listen to **** with. Didn't think anything of that threaded hole, I'll run in and grab a plug for it, and cap anything else I find on it before I go. I have to run to O'Reilly's to grab line for the transmission cooler, I'll grab these while I'm out.
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