Browning Posted September 9, 2010 Report Share Posted September 9, 2010 91 s10 just hit 195,050 miles. I have had some small problems with it in the past and overall it's a good running truck, until now. Went to town a little bit ago and on my way back I noticed a knocking sound coming from under the hood. Blocked the tires, started it up and attempted to find where it was coming from but only having one good hear it's hard for me to find the source of the noise. I hjave heard main bearing knock before and this isn't as loud and doesn't sound like it has the same tone. It does seem to get a little louder when the rpm's are increased but what I found odd is when I was checking for it, it went completely away a few times. What is a good method to finding out exactly where the knock is coming from? Really can't afford for this truck to be down nor can I afford to put another engine in it at the moment. I can't tell if it's in the bottom end or top. You can't hear it driving down the road unless you're in first or second. If it was a main bearing wouldn't it be very loud? Same with cam bearings? edit-just had the neighbor who is a diesel mechanic listen to it and he put his hands on the valve covers and said he can feel it in the passenger side and told me he thinks it's a collapsed lifter. Now, if this were the case would I be able to tell for sure by pulling that side valve cover off and checking for a really loose rocker arm? Quote Link to comment Share on other sites More sharing options...
Fubar231 Posted September 10, 2010 Report Share Posted September 10, 2010 Flat head screwdriver with wooden handle, put your ear against the handle ? Thats what ive always heard. Quote Link to comment Share on other sites More sharing options...
nurkvinny Posted September 10, 2010 Report Share Posted September 10, 2010 Piece of wood, about 2' long, broom handle diameter. Put tight against ear, move other end all over engine while running. Quote Link to comment Share on other sites More sharing options...
Browning Posted September 10, 2010 Author Report Share Posted September 10, 2010 never heard of those I'll have to try it in the morning. Some one on another site said if it's a collapsed lifter try some seafoam and that he's seen it free them up before. any truth to this? Quote Link to comment Share on other sites More sharing options...
EvoXbmx Posted September 10, 2010 Report Share Posted September 10, 2010 Pull spark plug wires one at a time. The knock will quiet down or disappear at the affected cylinder. This works sometimes, don't rely on it! I do not think it will work for finding main bearing noise though.... Just saw your edit: Funny you say that, because a friend I work with has a similar year s-10 with the 4-cyl, and he has a collapsed lifter. It comes and goes. It is hard to tell just by looking at your valve clearance for a collapsed lifter, because even though they are "collapsed" they still may have enough pressure to give the illusion that the clearance is good. Just gotta get your stethoscope out and trust your instincts at that point Quote Link to comment Share on other sites More sharing options...
Jizzle Juice Posted September 10, 2010 Report Share Posted September 10, 2010 scope? Quote Link to comment Share on other sites More sharing options...
BoostedAce Posted September 10, 2010 Report Share Posted September 10, 2010 stethoscope works Quote Link to comment Share on other sites More sharing options...
99FLHRCI Posted September 10, 2010 Report Share Posted September 10, 2010 Seafoam works wonders. Pour it in your oil and let it idle for a while and get good and warm and cycled through the engine. Maybe even take it on a short EASY drive and the come home and change the oil. Quote Link to comment Share on other sites More sharing options...
AJ Posted September 10, 2010 Report Share Posted September 10, 2010 vacuum tube works as well as a stethoscope in a pinch. Quote Link to comment Share on other sites More sharing options...
AJ Posted September 10, 2010 Report Share Posted September 10, 2010 p.s. its not a knock, its morse code for replace the pos. Quote Link to comment Share on other sites More sharing options...
Buckeye1647545503 Posted September 10, 2010 Report Share Posted September 10, 2010 drive it till it pops Quote Link to comment Share on other sites More sharing options...
Browning Posted September 10, 2010 Author Report Share Posted September 10, 2010 p.s. its not a knock, its morse code for replace the pos.lol it has needed to be replaced for a while now, just not in the budget. Does seafoam in the crankcase still smoke like a son of a bitch? I'm hoping it is something stupid like a collapsed lifter of bent pushrod but wouldn't I also head the rocker arms chattering? Quote Link to comment Share on other sites More sharing options...
Browning Posted September 10, 2010 Author Report Share Posted September 10, 2010 also, you can feel it when touching the passenger side valve cover. Would you be able to if it were something like a main bearing or cam bearing? Quote Link to comment Share on other sites More sharing options...
99FLHRCI Posted September 10, 2010 Report Share Posted September 10, 2010 It does not smoke when you put it in the crankcase as it is not actually being burnt (unless of you are burning oil then it may smoke a little bit more then usual however it will be diluted in 5 quarts of a smoke generating liquid anyways). Quote Link to comment Share on other sites More sharing options...
Browning Posted September 10, 2010 Author Report Share Posted September 10, 2010 nice so I won't have to worry about the fire department being called lol. truck doesn' smoke at all Quote Link to comment Share on other sites More sharing options...
Clifford Automotive Posted September 10, 2010 Report Share Posted September 10, 2010 Sounds like piston slap to me. If you hear it at start up then it tends to go away, this would be caused by the piston expanding under heat and starting to fill the void in the cylinder. Quote Link to comment Share on other sites More sharing options...
Browning Posted September 10, 2010 Author Report Share Posted September 10, 2010 complete opposite today. start it up and it didn't knock. After about 5 minutes of driving it started the knock Quote Link to comment Share on other sites More sharing options...
Browning Posted September 21, 2010 Author Report Share Posted September 21, 2010 what do I need to look for when buying a motor from a junk yard? Quote Link to comment Share on other sites More sharing options...
wnaplay1647545503 Posted September 21, 2010 Report Share Posted September 21, 2010 Go to a reputable yard that offers a warranty(although they typically arent for very long). I dont know if they will necessarily let you tear into one. Have you called an engine exchange type place that offers extended warranties? Quote Link to comment Share on other sites More sharing options...
99FLHRCI Posted September 21, 2010 Report Share Posted September 21, 2010 More pricey then a pick and pull but they have a 6 month warranty with optional extended warranties http://www.lkqcorp.com/location/sites.asp?L=44 Quote Link to comment Share on other sites More sharing options...
Richard Cranium Posted September 21, 2010 Report Share Posted September 21, 2010 what do I need to look for when buying a motor from a junk yard? 350. Quote Link to comment Share on other sites More sharing options...
Browning Posted September 29, 2010 Author Report Share Posted September 29, 2010 why in the hell would I want a 350 lol Quote Link to comment Share on other sites More sharing options...
Browning Posted September 29, 2010 Author Report Share Posted September 29, 2010 found a 3.4 with 88k on it guy wants $250 for it. Quote Link to comment Share on other sites More sharing options...
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