dead horse, 6.4 degas puked, stumped with other symptoms

[rcdan0108]

I know there are tons of old threads on this and the common answer is straight to heads for puking degas bottle. Been a heavy equipment for 20 years and this has me stumped. I think it is heads so lets get that out of the way. However, im 2nd guessing myself so im looking for someone with specific knowledge to the engines not just screaming heads heads heads. Not trying to be a dick about it either just asking for outside the box thinking.

With that being said I will explain. 08 6.4, 180k h&s, egr/dpf deleted, mild tune. Doesn't run hot, truck runs really strong, no coolant consumption, eot/ect within 2 degrees of each other. Only symptom, pukes from degas at 25-40psi boost. Sooo after 5 caps I pressure tested degas, 22 psi. Ok so swallow my pride and lets make a parts list but wait there's more. Here's what is really confusing, I've now performed probably about 10 combustion gas leak test with 2 different kits and chemicals, all passed?! Even after several of those doing WOT runs over and over. 1 more stumper that I know can cause higher coolant pressure but you usually get overheat with it. Upper rad infrared temp 170 ish lower 70 degrees after an 86 mile drive with 65 degree ambient Temps.

Again im not saying it's not HG's I'm trying to make sure I'm not about to dump 5k and a couple days of work into this and it be something as dumb as clogged rad or tstats. Side note I just discovered low temp on lower hose tonight and no I havent dumped coolant yet. Rad is only 2 years old. Tstats are easy just figured I would see overheat with one of those 2 being an issue.

Any thoughts would be greatly appreciated.

 

[Powerstroke Cowboy]

Have you hooked a pressure gauge up to the degas bottle yet to see the when it builds the pressure thats causing it to puke? This works really good to see if its boost related. I do this then run the gauge up and tape it to the windshield so I can see it while driving.

 

[6.0 Tech]

I know there are tons of old threads on this and the common answer is straight to heads for puking degas bottle. Been a heavy equipment for 20 years and this has me stumped. I think it is heads so lets get that out of the way. However, im 2nd guessing myself so im looking for someone with specific knowledge to the engines not just screaming heads heads heads. Not trying to be a dick about it either just asking for outside the box thinking.

With that being said I will explain. 08 6.4, 180k h&s, egr/dpf deleted, mild tune. Doesn't run hot, truck runs really strong, no coolant consumption, eot/ect within 2 degrees of each other. Only symptom, pukes from degas at 25-40psi boost. Sooo after 5 caps I pressure tested degas, 22 psi. Ok so swallow my pride and lets make a parts list but wait there's more. Here's what is really confusing, I've now performed probably about 10 combustion gas leak test with 2 different kits and chemicals, all passed?! Even after several of those doing WOT runs over and over. 1 more stumper that I know can cause higher coolant pressure but you usually get overheat with it. Upper rad infrared temp 170 ish lower 70 degrees after an 86 mile drive with 65 degree ambient Temps.

Again im not saying it's not HG's I'm trying to make sure I'm not about to dump 5k and a couple days of work into this and it be something as dumb as clogged rad or tstats. Side note I just discovered low temp on lower hose tonight and no I havent dumped coolant yet. Rad is only 2 years old. Tstats are easy just figured I would see overheat with one of those 2 being an issue.

Any thoughts would be greatly appreciated.

So on the 6.0/6.4 a combustion gas test is about useless. As you’ve said, it only pushes at higher boost. This is due to the bolts stretching under the heavier load, basically lifting the heads off the deck under the increased cylinder pressures. As powerstroke cowboy said, you can tie a pressure gauge into the cooling system and watch it while running it to make it puke. The only other thing that would be common are the egr coolers, but those are gone you said, so we can rule those out


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[strokemelongtime]

I had the same issue on my 6.4l, puking out the degas while under boost. Replaced the headgaskets and studded it along with a few other upgrades since it was all apart. no more puking!!