Whats the cause?
 

Ok so if you notice my post earlier the truck broke down today. I let the truck sit and then start it up and it purrs perfectly then I start having the same issue again pull over and it was making this noise
Did the same thing earlier too. I am thinking oil pump going out since it takes a while to start doing this? I check the oil and the level is fine I just had an oil change etc so I am at a loss here guys.

Re: Whats the cause?
 

That's a whole lotta rattlin' going on!. This is merely a guess, but sounds like the rod bearings are going out. Possibly time for a rebuild.

I strongly recommend NOT driving it, until it can be properly diagnosed.

Re: Whats the cause?
 

Why are you starting a third thread on the same problem?
( http://67-72chevytrucks.com/vboard/s...d.php?t=616466 )
( http://67-72chevytrucks.com/vboard/s...d.php?t=616323 )
It's better to keep all the info and replies on one thread.

Hard to tell what's knocking in the video, but it doesn't sound good.

Re: Whats the cause?
 

Was not trying to start a new thread, just that I got it running again and this noise pops into the picture. Kind of related kind of not I do not know....My issue is it does not always make this sound when it first starts up and is running it purrs beautifully. This is after like driving it for 30 minutes this starts. I can drive it around town all day but taking it out of town it does this. If it were the bearing (and correct me if I am wrong) but wouldn't it do it all the time?

Re: Whats the cause?
 

You can always keep driving it and whatever flies out the side of the engine was the problem.
OR
if you cannot find the problem, take it someone who can.
No one can accurately diagnose vehicle problems over the internet.

Re: Whats the cause?
 

Wow tincan I sense some hostility in that. I was not trying to knock your advice or anything it is appreciated. I agree a rebuild is needed, and I agree that it should not be driven until done. I was just trying to see if there is something inherently wrong with this that causes this issue, something that is common etc. I am new to this engine so I was trying to see, to me it seems very odd that it does it after running for a bit but runs great until that time. Maybe I am wrong this is common I do not know

Re: Whats the cause?
 

nope, no hostility, just being a smarta**

Re: Whats the cause?
 

Tin I actually am coming up to Caney, KS for a job....maybe I can bring it up to you and you can tell me what is wrong with it haha

Re: Whats the cause?
 

there's countless threads on here about people asking advise on "what's wrong with my truck" which normally end up as a big pissing match and arguments over differences of opinions.

The truth is, as I mentioned that no one can accurately diagnose issues over the internet and especially not intermittent/drivability problems. there are too many factors that could cause similar issues.

Some take it as mean, but I am just mentioning cold hard facts.

Re: Whats the cause?
 

C'mon up I am open Mon-Fri:chevy:

Re: Whats the cause?
 

You can use a wooden dowell as a stethoscope listening with your ear on one end and motor on the other. Move the dowelll around and see if you can hear anything before the noise becomes deafening. I'm thinking it's quieter at first because the oil is cold and thick. My guess is a spun rod bearing.

Re: Whats the cause?
 

The more you run it the more damage you are doing . Drop the pan and I'm sure you will find it.

Re: Whats the cause?
 

Yep. Time to reengine the fleet. Park it or itll die ugly.

Re: Whats the cause?
 

What engine is it ??????? the you tube video did not show up on my computer.. :gmc2:

Re: Whats the cause?
 

Straight 6 Keith...Probably a 230 or 250. I watched the video...Believe me....you don't want to listen to it. ;) Talk about a seriously ticked off engine.

Re: Whats the cause?
 

That does not sound good. Find a cheap 350/350 on craigslist, put a brick on the gas pedal making sure you film it, swap motors and go on with life.

Re: Whats the cause?
 

Yep thas morin one loose rod or slappin piston. If unbuttoned before any more damage is done it'll likeky be rebuildable or for 1500 get a reman 6 or abit more an 8.

Re: Whats the cause?
 

Not all these trucks have to have a 350 in them. These old 6's are just as reliable.
Matter of fact, I am getting ready to ditch my old worn V8(305) and go back with the inliner. And before I get bashed about it being a 305- it's just as good as a 350 and has 265,000 miles without being overhauled, just good maintenance by the previous owner of the donor.
Besides that- they rank up higher on the kewl factor. LOL!:metal:

Re: Whats the cause?
 

Hmmmm....doesn't sound good whatever it is. Time to pull it out and apart

Re: Whats the cause?
 

Get an I6, its ain't JAFSB, its More!

Re: Whats the cause?
 

AMEN BROTHA! Preach it like it is! :lol:

Re: Whats the cause?
 

sounds like miss and detonation. your gas tank is full of rust and scale. its getting pulled up to the filter where the suction is blocking the flow and the engine starts to run lean being starved for fuel. when you turn it off or it dies, the suction goes away and the rust/scale falls off the filter material. start it up and its powerful again, until the suction plugs up the filter.

clean out your tank.

Re: Whats the cause?
 

That is a dang good point....I think I had that or something similar to that happen to me...except my engine would just die. I do hear a miss when I listen to the video. :chevy:

Re: Whats the cause?
 

Biggest mistake people make with an inline is running them 75mph with 4:11 or even 3:70 gears. Inlines don't like that, they eventually make noises like yours and costs a bunch to make them happy again. Just because it's running smooth at high speeds doesn't mean it's ok. I agree it's not generally a good idea to diagnose problems on the net but your engine sounds worn out. Rod bearings shot.

Re: Whats the cause?
 

Well now . Thats an easy test. New fuel filter, clean the carb and test it from a clean one gallon jug o gas. If better purge apnd rebuild the fuel system. If not. Rebuild the motor.