Loud knocking, whats going on?

[Thor06]

Ok, as we were loading my DSM onto the flatbed to bring it home (after it overheated) we noticed a funny noise. It didnt do it (if it did, it wasnt as loud) the hour I drove it before it overheated. Well, I went to check it today and it was pretty loud. I would call it a louder knock. It wasnt high pitched and it wasnt low pitched, not grinding or squeeling, and I dont think it was like a pinging noise. Just a loud tick or knock. We could get a wiff of exhaust, but couldnt see where it was coming from. It was loud enough to the point of where it was hard or getting hard to talk over it. Definately coming from the timing belt side of the engine and probably on the bumper side, but where was damn near impossible to tell and I'm not ruling anything out. Heres what I was thinking:
Lifter Tick - sounds like lifter tick to me, but its awefully loud to be lifter tick
Rod Knock - doesnt quite sound like how its been described to me, plus if a rod was knocking that loud, I wouldnt expect the rod to hang around for more than a few seconds
Warped Exhaust Manifold - I've heard of the exhaust manifold warping people either able to hear the manifold knocking or maybe the valves seating or something
Hole In Head Gasket - When I overheated, steam was shooting out of the cooling system bypass valve (or whatever its called, but there wasnt a hole in the radiator or anything and steam was coming from under the passenger side of the radiator). Well, I would make sense to me that the stock felt gasket was already weak in that area and when all that pressure came, it just blew part of the gasket out and we are just hearing the cylinder firing.

What do you guys think? I am leaning toward the hole-in-the-head-gasket theory. The oil pressure guage wasnt reading anything so I thought that maybe the oil pump was out of order and underlubing everything, but there was still oil getting to the head and it ran for an hour with out faltering in temp before it overheated (we figured it overheated because of air getting into the system because of the head gasket leak). What do you guys think, am I making sense?

[wanaplay134]

i wouldnt even mess with that i would rip the engine out and check and regasket everything being your going to have to now anyway. its probally rod knock if its that loud.

[MexRocket]

Well, I have never heard of that, but I am sure you could be right. Yes I know I contradicted myself in the previous sentence. I have the same sound, but mine isn't as loud as you say it is, actually mine IS lifter tick. (Only happens when it's real cold out) If you could smell the exhaust, could be the head/exhaust gasket, or turbo/exhaust manifold.

Are all your studs in? How bout Manifold turbo bolts? When you increase the throttle how loud does it get? Did you let it run for like five min? But if the gasket is already on the go, I would asume your theory holds up? right?

The only way to find out is, take the head off and start the rebuild a little sooner than you wanted. Spring is almost here, so get two propane heaters and have them next to you as you work outside! =P I really don't have an advanced grasp on the internals yet of the engine, but I understand it for the most part. Whatever you do, good luck and take lots, and lots of pics.

[Thor06]

What was that? Some thing intelligent from MexRocket? Just playing man.

We are actually missing one turbo bolt and atleast one exhaust manifold bolt and the guy said it had lifter tick when I bought it, but this just seems too loud.

Could it be something wrong with the oil pump? What about a loose/broken belt or something along those lines? Maybe snapped balance shaft belt?

I dont want to rebuild the bottom end until I ablsolutely have to so I am going to do the other stuff first. I will refill the coolant and run it for a little while either this week or on saturday. I will see if the sound changes with rpm or warming up and stuff. Also, cant you test rod knock by unplugging each spark plug by itself and if the sound changes then rod knock is possible? I will also compression test, if the cylinder by the timing belt doesnt have much compression (thats where the sound was coming from remember) I would lean towards the head gasket idea. If none of those tests point to anything, then I will just resurface the exhaust manifold, get the rest of the turbo/manifold bolts, do the head gasket and head rebuild, and clean the lifters and pray that it went away. Any more comments or ideas?

EDIT: I get to use my moms work building. Mmmmmm solid floors and heating.

[EDMUND65]

Welcome To The World Of Dsm Where Nothing Ever Works Right And You End Up Putting 4 Grand More Than The Cars Worth Trying To Fix It.... Good Luck Man And I Have No Clue What It Could Be

[ez1286]

Take plug wires off one at a time and see if it changes, if so rod knock. be very careful not to ground yourself while doing this. (happened when i had the evil eclipse (red one that tried numerous times to kill me))

[MexRocket]

Originally Posted by ez1286

Take plug wires off one at a time and see if it changes, if so rod knock. be very careful not to ground yourself while doing this. (happened when i had the evil eclipse (red one that tried numerous times to kill me))

that was some funny shit, "Uh... I think I'm bleeding." As blood pours outta of his wrist dripping everywhere. Thor actually not having a turbo bolt in there WOULD make that sound, I would know, because... I have 2 studs missing, and a bolt that is 2 washers short of being actually in there. IT makes a loud clicking kinda of noise that you are talking about. But, it may be something different with your car, it sounds like there are some problems.

[Thor06]

How will the sound change when you unplug the wire? Will it stop or just get quieter? Also, if a rod is knocking its because the bearings burned up right? Then wouldnt you be able to grab the rod and kinda click it back and forth on the crankshaft?

I thought about it more and I guess I still think its the head gasket. That would also explain why it got progressively louder. I guess I will get a turbo bolt, exhaust manifold bolts, change the head gasket, and PRAY it stops. I guess while the head is in the machine shop (which will probably take a while, my dads friend (discount?) is going to do it but hes a good two and a half hours away) I will take off and re-RTV the oil pan and give the rods a shake. If it does need to be rebuilt, like 75% of the work for taking the engine out will already be done. Suggestions, comments, and thoughts still strongly encouraged to show themselves .