motor knocking - The 1947 - Present Chevrolet & GMC Truck Message Board Network

iride · 01-24-2008, 09:59 AM

Hi all I have a 79 1/2 ton 4x4 that the only thing its ever been used for was plowing and the body is shot! It has a 350 and has always had a knock and i have babied it cause its mainly for plowing my long driveway. Yesterday i pulled it out of the shed and it locked it up and wouldnt start till i got a booster charger on it. It was stuck and when it came free WOW did it knock then!! I guessing its a rod problem it still has 20 lbs oil pressure and runs ok but is very noisy. My question is what can be done to limp it by till spring so i can junk it!! I poured in a quart of stp but didnt know if anyone had any other ideas. I dont want to tear the motor down its to dang cold for that! How many quarts of oil can I put in it and would that help at all?
Thanks
Todd

gchemist · 01-24-2008, 10:05 AM

A rod knock is only a time bomb. It can fail at any time. The bearings will fail eventually. Keep the RPMs low. If the oil pressure is only 20 PSI, it won't last long.

iride · 01-24-2008, 10:11 AM

It has had 20 lbs for the last 2 years. What will happen when the riod lets go?

**old Rusty C10** · 01-24-2008, 10:11 AM

dont bet on it making spring... the bears have a better chance at the superbowl this year

89 crew · 01-24-2008, 10:17 AM

At 20 lbs it can handle 2000 rpm if everything inside the engine is right. since you have a knock no telling. If it is a rod and it lets go it will most likely throw it through the side of the block or the oil pan. The engine will be toast. Where is the knock coming from? does it sound like a rod, or could it be something else?

iride · 01-24-2008, 10:20 AM

I spun a rod bearing before on a car and it sounded like that but now its louder. Its definatly on the bottom end

89 crew · 01-24-2008, 12:10 PM

Call the undertaker. It is either dead, or soon will be. If you are serious about scraping the truck then drive it only in areas you won't mind oil being spilled. It will spill, and probably sooner instead of later. If you want to keep it around, drop the pan and find out what is wrong.

Damien · 01-25-2008, 04:08 AM

Put some 80w-90 in it. Sorry I couldnt resist.

01-24-2008, 09:59 AM	#1
iride Registered User Join Date: Sep 2006 Location: illinois Posts: 54	motor knocking Hi all I have a 79 1/2 ton 4x4 that the only thing its ever been used for was plowing and the body is shot! It has a 350 and has always had a knock and i have babied it cause its mainly for plowing my long driveway. Yesterday i pulled it out of the shed and it locked it up and wouldnt start till i got a booster charger on it. It was stuck and when it came free WOW did it knock then!! I guessing its a rod problem it still has 20 lbs oil pressure and runs ok but is very noisy. My question is what can be done to limp it by till spring so i can junk it!! I poured in a quart of stp but didnt know if anyone had any other ideas. I dont want to tear the motor down its to dang cold for that! How many quarts of oil can I put in it and would that help at all? Thanks Todd

01-24-2008, 10:05 AM	#2
gchemist BAD BOW-Silverado XST Join Date: May 2000 Location: Senior Member from Austin, TX Posts: 6,431	Re: motor knocking A rod knock is only a time bomb. It can fail at any time. The bearings will fail eventually. Keep the RPMs low. If the oil pressure is only 20 PSI, it won't last long. __________________ Gerardo a.k.a. Mad Chemist Silverado XST videos

01-24-2008, 10:11 AM	#3
iride Registered User Join Date: Sep 2006 Location: illinois Posts: 54	Re: motor knocking It has had 20 lbs for the last 2 years. What will happen when the riod lets go?

01-24-2008, 10:11 AM	#4
old Rusty C10 Robert Olson Transport Join Date: Oct 2002 Location: recent transplant to NC USA Posts: 20,310	Re: motor knocking dont bet on it making spring... the bears have a better chance at the superbowl this year __________________ Bob 1951 International running on a squarebody chassis "If a man's worth is judged by the people he associates himself with, then i am the richest man in the world knowing some of the fine people of this board" http://67-72chevytrucks.com/vboard/a...t.php?f=25&a=9 (you can review the site rules here!) PM Me for your vehicle/parts hauling needs in the North East US or see my Facebook page Robert Olson Transport Live each day to the fullest.. you never know when fate is going to pull the rug out from under you... I hate cancer!!

01-24-2008, 10:17 AM	#5
89 crew Registered User Join Date: Mar 2006 Location: Kansas Posts: 865	Re: motor knocking At 20 lbs it can handle 2000 rpm if everything inside the engine is right. since you have a knock no telling. If it is a rod and it lets go it will most likely throw it through the side of the block or the oil pan. The engine will be toast. Where is the knock coming from? does it sound like a rod, or could it be something else?

01-24-2008, 10:20 AM	#6
iride Registered User Join Date: Sep 2006 Location: illinois Posts: 54	Re: motor knocking I spun a rod bearing before on a car and it sounded like that but now its louder. Its definatly on the bottom end

01-24-2008, 12:10 PM	#7
89 crew Registered User Join Date: Mar 2006 Location: Kansas Posts: 865	Re: motor knocking Call the undertaker. It is either dead, or soon will be. If you are serious about scraping the truck then drive it only in areas you won't mind oil being spilled. It will spill, and probably sooner instead of later. If you want to keep it around, drop the pan and find out what is wrong.

01-25-2008, 04:08 AM	#8
Damien Registered User Join Date: Mar 2007 Location: Farmington, MN Posts: 928	Re: motor knocking Put some 80w-90 in it. Sorry I couldnt resist. __________________ I can still count my vehicles on two... wait three hands.



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