Wet EGR valve and puking! Help!

[awesomewrangler]

Ok, I've searched not only this forum but several others before posting and need your opinions before I start the parts gathering and subsequent tear down of my truck. 2004 ford f250 6.0L, 167k miles and counting. I've owned the truck the last 3 years with very little trouble. New batteries, new ficm, new alternator, new HFCM, and new regulator all in the last few months. A couple of days ago I noticed the white stains around the radiator cap. The level has been kept at the low fill mark cold and has stayed there the last 3 years until now. I cleaned the egr valve two days ago and found it nasty. Almost completely clogged with thick, wet, sticky soot. I begin thinking egr cooler is leaking because it did seem damp down inside the intake manifold. I have been monitoring my deltas and are fine, between 4-8 degrees always. I've ordered the rcd egr kit to hopefully take care of the leaking and prevent a possible problem down the road anyway. I don't see any white smoke and truck seems to run strong to this day. I don't tow or hotrod the truck. I have two sct tunes that I run, extreme street and Matt's SRL tune. Here's my question: When I shut the truck down, I pop the hood and can faintly hear a hiss from my radiator cap. I'm pretty sure the cap is bad because even if I'm easy on the truck it's still hissing from the cap. I am losing a little bit of coolant, just enough to be noticeable (a few ounces) every couple hundred miles. It is possible that cap is bad, egr is bad, and headgaskets and oil cooler are ok? How would you proceed from here? I will do all my own work on the truck. What I don't want to do is the egr cooler delete now, reassemble, and then have to tear down again for headgaskets.

[justa03]

If the HG's and EGR cooler are out there is no way to tell which one it is unless you pull the EGR cooler and pressurize it under water and see if air bubbles come out of the coolant ports with the exhaust ports and the exhaust side pressurized. If the cooler is failed you are going to have to replace the EGR cooler first and then test for HG's or just do it all at once. If you EGR valve is wet I would say your cooler has failed and time to to the delete. The cap more the likely is bad and not that uncommon so just replace it and anyways its kind of a maint item. You should be watching your deltas under a heavy load. You can also test the pressure in the cooling system with yoru boost gauge by putting a T into one of the coolant lines in the degas bottle and go drive it. If you see over 17 psi I would say you either have a EGR cooler leaking or HG's but due to the fact your EGR valve is wet id would go after the cooler.

[awesomewrangler]

Thanks for your response. I've got the egr delete on the way. If I pressure test the system as it is right now (poss bad egr cooler and bad head gaskets), will just a bad cooler alone cause coolant pressures above 16 psi? Is there anyway to determine bad headgaskets before the egr is tested and/or deleted?

[justa03]

No cuz if your pressure test the system its telling you that you have a leak but then you have to find where its coming from. With the EGR cooler leaking or HG's leaking you will show boost pressure in the system due to the exhaust through the EGR cooler. HG's shouldnt make your EGR valve wet that will just go out the exhaust for the most part and be burnt up in the cyls and cause the degas bottle cap to vent from excessive pressure.