Seafoam is nothing like marvel mystery oil. Seafoam is a solvent, its not ment to improve oil or gasoline its a cleaner plain and simple. Its cleans injectors out and buildup on the valves when used through the gas, when added to oil it breaks down sludge and oily buildup on internal parts, it also thins out the oil which is why it can only be used and let the engine idle then the oil has to be changed right after and not driven on or it will damage the engine from lack of lubrication

 

EXACTLY

 

I know the sound is not bottom end because I can't hear it when I put the screw driver on the block. It also goes almost completely away when warm. The only place I can hear the sound is around the #4 cylinder exhaust, The #4 Cylinder on the valve cover and on any valve cover bolt.

 

That doesnt mean it cant be bottom end. the wrist pins will get quieter as the engine warms up and everything expands. just keep an ear out and if the noise gets worse you know it could def be bottom end. If you seafoam it, you will clear up any gunk build up and should be able to hear the sound more if its in the bottom end

 

Heres a pic of the manifold crack

 

That could definatly be your noise. I had an Elantra with a cracked manifold and it sounded like head noise and got quieter after warming up lol

 

Actually... I've considered this since I use seafoam before every oil change. Letting it idle is typically not enough. I do like the manufacturer says:

"To clean built-up oil residues and contamination from the crank case, add 1½ oz. Sea Foam® to each quart of engine oil. Sea Foam® will slowly re-liquefy residues and suspend contaminants for easy removal. Monitor oil for color and clarity and change oil and replace filter when oil looks dirty."

So basically - check your oil, note the color, add seafoam, drive the car and let seafoam do its thing, then when the oil changes color or darkens replace it

 

removing of some of these contaminants that form around the various oil seals on older engines will leave areas for oil to leak.

 

If crud, grime, grease, varnish or carbon is plugging a leak in a seal, then the seal needs to be replaced anyway.

 

Exactly. It's not logical to denote a product as having a negative impact simply because your motor needs repair.

 

i was simply providing a warning. im sure many people will read this and dump seafoam in their motor thinking of how clean they are making their engine and trying to make their vtek hit harder. most of these people probably dont realize they could be needing to replace a seal or two and end up with some really unwanted leaks

but i agree mike. a bad seal definitely needs replacing. i guess seafoam can also be a good way to find out if your seals are failing before they really go

 

It's actually a great way to locate that exhaust leak you've been looking for. Just look for the smoke blowing out of a gasket.

 

It's also a great way to smoke out your neighborhood. Dump some down your spark plug holes and take it for a drive :D

 

I've used a shop vac in reverse to find exhaust leaks - tape it to the tailpipe when the engine is cold and listen/feel for leaks. Amazingly the hiss can be heard from about a foot away when the shop vac is running if the vac is as far away as it will reach.

I would sure believe that manifold leak (pictured) is noisy. The thing about exhaust manifold leak noise is that it can't be heard on a mechanic's stethoscope, so if there is still noise coming off the engine itself there is something else going on. I confess I have never dealt with wrist-pin noise, so I defer to those with experience in it. My experience with rod knock and exhaust leaks is that leaks get louder with increased throttle, while rod knocks become slightly harsher but not much louder.