I would agree with you but if I put my hand on one the passenger side of the pan it seems I can feel it, although I'm sure things like that can travel all over. Its a manual, but putting it in gear and putting any load I can on it seems to do nothing. I have seen some on youtube that sound darn close, and have heard some that are WAY worse. All the exhaust and manifolds up front are all original so a crack or leak is certainly possible. Frustrating.

 

if it were me I'd pull the manifold and inspect it... it's the cheapest out at this point...

Doughnut gasket can do that as well... you'll see black carbon tracking where the leak is

 

I am going to inspect all that in the morning for sure! A question though...aren't those old manifold bolts going to be a bear to remove? Our worse, break off? I know one thing...from watching some vids, there are alot worse sounding engines than mine by far out there. I am really starting to lean towards this exhaust situation. That would be awesome...considering....and give me a great excuse to put some headers on! we'll see.

 

I drench them in tranny fluid cold and fire it up and keep squirting them... when they are hot and the engine is running I try breaking them loose...

as far as the bolts where the pipe hooks up if you happen to brake them after the fluid drench... use MAPP gas torch and heat them cherry red and use a breaker bar and socket... and work them out while red.. back and forth dont just twist them out... never broke one off this way

 

thought I would update. Late last night I went out and took a quick peek.. low and behold, on the left side of the engine, where the manifold bolts to the block, there is a bolt that must be sticking out a good 1" to 1-1/2", not tight thats for certain, and there is some black above this point, however it certainly sounds to me as if the sound I am looking for is coming from the opposite side of the engine. When I have got out of my truck from starting it before, I would almost think the sound IS coming from the exhaust, even further back... mid truck or further back.. but when I get under it, I'll be darned if it doesnt sound as if its coming right from the bottom of the pan. I know that sound can travel an just be totally flat out weird. on a side note, if I happen to break a manifold bolt off in the block with nothing to get hold of, how am I going to get that broken bolt out?

 

Something different this morning. This is by far the coolest morning we have had here in over a month... thinking if something is contracting and expanding I went and started it up... this time when I started it, there was no knocking for the first maybe 10-15 seconds, then it started but didnt seem as noticeable as previously.. I shut it down at this point. Thinking was, if whatever is causing this sound contracted a tad bit more because of cooler temps, gap or whatever got a little larger.. something happened because there was no noise upon immediate startup. This really makes me think it could be an exhaust issue? Just thought I would mention this as the ambient temp is considerably cooler than we have had pretty much since I have first noticed this sound. Possibly coincidence, but thought I would throw that out there.

 

entirely possible... even though the metals are the same ambient and engine temps play a huge factor in their expansion and contraction rates...

with the manifold to engine bolts give them all a good few raps with a hammer like you're trying to beat them into the head... this will shock any rust in them and then do the same loosening with a breaker bar and socket... just wiggle them back and forth a few times to get it loose and back it out then wiggle more back and forth and back out... if it feels like its getting tight then turn it in and wiggle more back and forth then loosen... take your time. I;ve never broken any off this way either...


if you do snap one you can always drill and tap

 

Ok, I replaced that manifold bolt that was basically doing nothing... no difference in sound.. however I did get out my stethoscope.. I put it on the pan and it sounds fine down there... exhaust all sounds ok... the place I pick up the noise the most is on the drivers side valve cover just behind the oil fill. Maybe thats not where it is coming from, but that is where I could hear it the best. I honestly could not hear anything out of the ordinary with the stethoscope where I thought the noise was coming from, which was the pan, and I thought it was on the passenger side. I can here a bit of tick tick tick on the passenger side valve cover, but seems to be consistent all along it, I pick it up the most, drivers side, mid valve cover, right in the middle.. move it closer to the outside of the cover and its not as strong as when I put it right in the center. Things just dont seem as bad today, dont know if its becuase its cooler outside or what.

 

still could be an exhaust leak... nothing in the valve cover would knock... it will all go tick, tick as thats the sound of the lifters and the valves opening and closing and if there is a slight tolerance you'll hear the lifter, pushrod and rocker tap the valve tips... thats not uncommon....

 

I will have to get a vid after she cools back down so you can listen. One guys knock might be another guys tick. I know I sure heard REAL knocks watching some vids last night on youtube. Its the only place I could really pick it up. What I thought sounded like it was on the bottom, I certainly couldnt pick it up with the stethoscope. I tell ya, when I get out of my truck, it alsmost sounds like its coming from the rear of the truck, till I get up by the engine. I was getting rather frustrated as with the stethoscope I just couldnt track it down, then I touched the valve cover and I could hear it.. maybe thats not where its coming from, but must be close. I touched the exhaust manifolds and several other places on the exhaust, couldnt hear anything.. I will get a vid and you can have a listen. Im certainly not calling it good yet, but feeling a little better than I did about it.