91 k1500 knock

[kjeff1990]

my truck has been knocking for about 4 months now. the sound is coming from the bottom towards the front. it knocks only when the engine is hot and the knocks gets faster when i accel. people r telling me all different things. can anyone help. its a 91 gmc sierra 5.7 350 with 160k miles.

[1500cheyenne96]

Is it a deep hollow sounding knock or kinda of a tick tick sound? A good test to narrow down exactly where it is it to start the truck and when it stars knocking use a screw driver or stethoscope moving it around till you can here it the best. Just be careful not to get entangled into the pulleys

[Crmzendrgone]

Originally Posted by 1500cheyenne96

Is it a deep hollow sounding knock or kinda of a tick tick sound? A good test to narrow down exactly where it is it to start the truck and when it stars knocking use a screw driver or stethoscope moving it around till you can here it the best. Just be careful not to get entangled into the pulleys

another way use a screw driver as long as you have and start it up just like 1500cheyenne suggested and get underneath it put the driver to the oil pan if you hear it real well then thats your best bet that it is in the lower end. probably a bearing gone bad.

[hotrodpc]

Hate to hear that on a motor with only 160,000 miles. Have you had this vehicle all its life? Maybe a neglected engine. If its only doing it when hot, and you know the engine is on its way out anyway, you may try running some 20w-50 motor oil in the thing and see if that helps at all. But, all that is going to do is prolong the inevetible, and possibly get a few more miles out of it. Of course my suggestion is assuming its a rod knocking. Hopefully that is a wrong assumption, but being that you are noticing it when its hot and the oil is thinner, I am thinking rod knock. Obvously its not to profound as of yet, or you would certainly know its a rod knock.

[Crmzendrgone]

Originally Posted by hotrodpc

Hate to hear that on a motor with only 160,000 miles. Have you had this vehicle all its life? Maybe a neglected engine. If its only doing it when hot, and you know the engine is on its way out anyway, you may try running some 20w-50 motor oil in the thing and see if that helps at all. But, all that is going to do is prolong the inevetible, and possibly get a few more miles out of it. Of course my suggestion is assuming its a rod knocking. Hopefully that is a wrong assumption, but being that you are noticing it when its hot and the oil is thinner, I am thinking rod knock. Obvously its not to profound as of yet, or you would certainly know its a rod knock.

I had a JEEP Cherokee come in 4.7L, heard that thing from a 1/4 mile away. To bad the owners didn't have the money it would have been a nice payday for me I like the 20w50 idea, I had a 4.0L straight 6 cherokee come in with lifter noise the cam bearings spun so they were not getting enough oil. We threw straight 50w in that bad dog owner drove it out quite as a mouse sold it that weekend. I feel bad for the new owner

[hotrodpc]

Originally Posted by Crmzendrgone

I had a JEEP Cherokee come in 4.7L, heard that thing from a 1/4 mile away. To bad the owners didn't have the money it would have been a nice payday for me I like the 20w50 idea, I had a 4.0L straight 6 cherokee come in with lifter noise the cam bearings spun so they were not getting enough oil. We threw straight 50w in that bad dog owner drove it out quite as a mouse sold it that weekend. I feel bad for the new owner

I know of a guy who put a quart of 90w gear oil with 4 qts of 30W to shut up an engine. Worked great long enough to get it sold. That was an old Ford motor. Not sure how those mixes would work in todays engines.