Allrighty, Dr.... I found an old post that you posted, someone was asking "what this is" and you said it was the diverter valve... this was on a 4.9, not the 302 that I have. I believe mine is in the REAR of the engine? Kinda back in there where you cant hardly see the darn thing? Seems like things I work on are always like this. LOL

 

could be... unless I went to my buddies and looked at his truck (302) I wouldnt remember off hand... looks like we're both shooting in the dark

 

lol... Ill spend some time on it sometime this weekend.

 

Morning update... took the serp belt off real quick and started.... started prior for a baseline listen.. took belt off.. noise still persisted although it didnt seem as loud. That makes no sense to me but thats what I got. Still cant locate that diverter valve. Let it warm up, unplugged and pluged in the coolant temp sensor several times, made no difference whatsoever. by this time it had quieted down to where I could no longer investigate. So frustrating.

 

Wellll, I started pulling the exhaust manifold bolts on the drivers side.. I dont think any of them appeard to be tight to spec. Pulled them out, and reinstalled or replaced and torqued to spec. on 3 of them however, how do you get them out? They are pretty rusty, and have a bracket attached with a little nub on the end.. how do these come out? It LOOKS like the head of the bolt is not up against the manifold, and I know the front one which I replaced, was very black, barely had a head left on it. I was truly amazed how easily they all came out. Started it up when I got done with the ones I replaced and to my surprise, the noise was not near as bad as it was before. I had been starting and shutting it off after each one, just to see.. so will wait until it is truly, completely cooled down before I can say for certain, but the gauge was in the cold range, and it was much better, SO, may be on to something here. get the other side done as well, and figure out how to remove the ones with the bracket attached, this might solve my problem. I will be one happy camper if it does I can tell you that much!! Past few days I have been thinking it may just be the end of my ol girl and I may buy a new truck. Something I really dont want to do as I love my truck, and another one of the same age... just wouldnt be the same to me. If this fixes the issue, a full restoration begins this winter. If not... I have to decide what to do. But a new truck... or add the engine to the restore. From mechanics I have talked to, and who have seen my truck, know how I drive, they tell me 260,000 just really isnt that many miles anymore and they dont believe its internal. If this doesnt fix it, I am dropping it off so they can listen to it some morning next week. ONE MORE THING... from the factory, was there a gasket installed on the exhaust manifold? If so...with the bolts as loose as they were.. i imagine a new gasket would be in order if I determine 100% that it is where the sound is coming from. If so, may let it go until winter (have only driven it 3000 miles since Feb) and put headers on it. Right now, I am feeling pretty good. Im very tired today though, its heating up outside, and I think the rest will have to wait until tomorrow.

 

Yes there are gaskets on the manifolds from factory, and yes all the valves for the smog system are on the back of the engine, can't name off each one right now but there is one nearly dead center behind the engine between the tubes running to each head.

As far as removing the bolts from those brackets all that held them to my bolts where some nuts just spray them down with pb blaster or your choice of penetraiting oil put a wrench on the nut.

 

I think some also have metal bent over the heads so they won't viberate loose, I think its been a while since took them off to have my heads worked.

 

Hmmm, ok, they are pretty rusty looking. I will have to clean them up really good and see what I can do. Cant be too difficult, just didnt look like there was anything to get a wrench on, but I will take a closer look. Went out again and started it up, temp gauge was pegged over on cold, darn thing barely made a noise. Im still not 100% convinced that this is what it is, but gotta say I am feeling pretty good about it!

 

ok, I cut the damn bracket off. the nuts that held it on were literally welded on to the bolts, no threads showing or nuthin. will have to rig up a new bracket to hold the dipstick tube, but it has been broke for a long time. replaced those 2 bolts, and sounds a little better yet. those two bolts were not tight against the manifold at all. Still making a noise, but maybe not even half of what it was. Probably tackle the passenger side tomorrow. if that doesnt cure it, I am guessing it needs new gaskets. At this point I am not thinking its anything internal.
Dr.. if it hadnt been for you I probably wouldnt have even started checking all the exhaust etc... I owe ya one! Thank you!
I am planning on keeping my truck around for a couple hundred more miles or more, and doing a total restore this winter unless things take a turn for the worse and it turns out NOT to be an exhaust leak... but.... me thinks it is. Happy Happy Day!!

 

You're welcome man.... thats why i am here. I've worked on thousands of vehicles and I've found a lot of weird things in my day....

you did good describing the issue