If you want the history see my threads from October. Short story is I am still losing coolant. I've tried two different Ford dealers and neither was able to solve the riddle.

I hooked up the trailer and headed for Mississippi on wed morning. It was cold but otherwise a routine trip. About 50 miles or so into the trip I stopped at the Alabama welcome center. just for grins I checked the hood and sure enough there it was, coolant puke on the degas tank. So, I continued on, checking a couple times along the way. Truck did not get hot (200 degrees or so), just like last time. I found no signs of external leaks. Truck ran and towed great. No codes or lights. Had I not opened the hood and looked I would have not known I had a problem.

At each stop I found the coolant had receded to a level just above the small return hose. When I loosened the cap the pressure would release and the coolant would rise to a normal looking degas level. I believe that prior to this problem starting the hot coolant level was up near the top of the degas tank.

Today it took 24 ounces or 1.5 pints to raise the cold coolant to the normal level. I lost that in 300 miles or one half pint each 100 miles. I went back and checked ant that is the same rate of loss I experienced last summer/fall.

Other factors bearing on the problem.

All external leaks have been repaired
No coolant in oil ( Blackstone)
I tested for exhaust in coolant, test was negative.
No white smoke.
No coolant visible in tranny fluid.
Coolant system will hold 16 PSI for 6 hours or more but not overnight.

I am open for suggestions. Thanks

 

The pressure loss over night could simply be the coolant cooling down.
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Have you tested the degas pressure cap, I have replaced mine 4 times so far the newer updated one seems better. If you look inside you will see they have upgraded the spring assembly, just a thought. I know 1 out of 4 trucks I check has a bad cap, there nothing special I believe it’s the same cap they run on several different vehicles

 

Mine does the same thing, only once in awhile-maybe when it does a regen and gets a little hotter than other non-regen drives. I notice a little streak of coolant down front of degas bottle coming from cap. When it dries it leaves some white residue where coolant streaks down, and a couple times now has left a little puddle on garage floor. I plan to add a new cap to the list of parts needed when the egr's get blocked off and coolant flushed.

 

Stanley,

I've been (??) down the same road where my degas started puking and it also passed all of the tests you talked about.

My "fix" was a new cap and the updated degas bottle which, so far, has seemed to stop the puking no matter how hard I get into it with the skinny pedal.

Don't know if this is a fix or a band-aid as I only have a few thousand on the new tank/cap, but here's what I do know:

- fill line on the new tank is considerably lower than the original (memory says maybe as much as 2"), my conclusion is the old bottle promoted overfilling and too little expansion volume.

- the port (overflow return) is above the full mark, which I don't see this directly affecting the puke, but the old mentallity was the level HAD to be above the return port, which again may have resulted in overfilling.

I'm not a 100% confident in this fix as I didn't note any puking until my truck hit 136k miles and the 2nd radiator was replaced. That may have been because I really didn't monitor for it at that time.

At the same time, Ford did see a need to re-design the degas bottle for the 6.4s, so there must have been a note worthy problem driving them to do something.

Hope you find a good fix.

 

If you call Stanley, I had mentioned previously to sand the contact area for the cap before replacement.

Unfortunately now I think a new degas bottle is in order.

 

If you decide to try this, I picked up the degas bottle from Ed at www.horizonpartsguy.com for about $120 and the cap was about $7.00.

 

Oh yeah, cap is the new model and checks OK.

 

Thanks guys. I'm on my third cap and it checked good last week.

The over night pressure drop happens with coolant at room temp.

Senix, you know I do everything you say, I sanded the rim and when I get home next week I'll update the degas.

What troubles me is this: Instead of expanding and filling the degas to a higher level like it used to do, the hot coolant is lowered in the degas tank and expands and refills it when I release pressure at the cap. What's up with that.

 

You changed the boiling point by releasing the pressure.

 

Stanley,

I would be half tempted if I were you since you'll have to drain the antifreeze would be to slip some block off plates in the coolers, I think you could leave the coolers intact just see if you could slip the plates in place, that along with blocking off the water supply to the coolers would totally remove them from the equation.

I see you left home for warmer weather, I must be nut's, we just got back from Marquette Mi, last night, was -2 degrees when we closed the camp door at 6:30 yesterday morning.

 

Stanley,

If you get a new coolant reservoir, as mentioned above the bottle will have a new "fill line" on it. It will be lower on the tank than yours now. You will also note the change around the venturi TSB that had been done on all '08s. I pulled my '10 beside my work '08 and the changes were pretty noticeable to people who pay attention to 'stuff' I truly wish there was a way to 'inject' more coolant into the system without removing the pressure cap, like Senix said, every time we do, we would change the boiling point by adding in air. My '10 only used about 1/3 of a gallon in the 21k miles that I had her but 95% of those miles were pulling hard. Not as heavy as you, but pulling still. These plastic tanks have really concerned me since I had to replace on my Excursion last summer. They were the same tank, but when I got the old one out and compared it to the new one, the difference between the two was remarkable. The old one had swelled dramatically and was much 'harder' due to all of the heat cycles. I think some where along the way, this might play a little something into your problem.
I will keep asking and looking to see if we can figure out what's up with your truck. In the mean time, keep some extra coolant and get an extra Stant cap part number 10238 with you. My one puking episode ended with a new cap like this. I think I posted this before and forgive me as I think you've seen it, but here it is again about the caps.

 

<style> <!-- /* Font Definitions */ @font-face {font-family:Cambria; panose-1:2 4 5 3 5 4 6 3 2 4; mso-font-charset:0; mso-generic-font-family:auto; mso-font-pitch:variable; mso-font-signature:3 0 0 0 1 0;} /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0in; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-ascii-font-family:Cambria; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:Cambria; mso-fareast-theme-font:minor-latin; mso-hansi-font-family:Cambria; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} @page Section1 {size:8.5in 11.0in; margin:1.0in 1.25in 1.0in 1.25in; mso-header-margin:.5in; mso-footer-margin:.5in; mso-paper-source:0;} div.Section1 {page:Section1;} --> </style> Just curious when you said it checks out, are u actually testing the cap to 16 psi with a tester or are u assuming the cap is good because pressure is present in the degas bottle? Pressure can be present in the degas bottle with a cap that only holds a few pounds but is well out of spec. With that being said simply adding a new one with out checking the new one could be an issue as well. I have had brand new caps fall short of the proper psi spec and it doesn’t take much to significantly raise the boiling point with coolant.


Just for clarification the cap on the left is the old style, the new style is on the right. The new style has a larger spring that is not as prone to fail as quickly.

 

Cap holds 16 PSI for hours, did not check beyond that. And, yes I have a gallon of coolant I mixed myself so I know it's gold and exactly 50/50. Or at least close enough that I think it's exact.

Boiling point. OK, a loss or reduction of coolant lowers the boiling point, right? A lower boiling point will cause the truck to puke at a lower temp, right? The puke will further reduce the coolant which will lower the temp at which it pukes and so on. It will all be stopped by either lowering the temp, (ie: slowing down or having an easier drive) or by adding coolant. And keep in mind that in the middle of my puking episodes last fall I towed 350 miles over several high passes in western Montana with no puke and no loss of coolant. I just double checked my records to verify that.

But it's a chicken and egg riddle. Did my truck puke this time because the coolant was low or was the coolant low because it puked? Keep in mind the temp never exceeded 200 degrees this time.

I always thought hot coolant expanded and I'm pretty sure that once warmed up the visible level in the degas tank used to be well above the cold fill lines. Now it is well below the cold fill lines. So is it contracting? Not likely. When I release the pressure the coolant comes back up to normal level.

Is it likely that the compression of the coolant is the result of an outside element (head or EGR cooler) adding pressure (exhaust) of more than 16 PSI to the coolant system? I sure hope not.

To add to the riddle I just went back through my truck diary and found that I have had a slight coolant loss since 17,000 miles. just 4 or 6 ounces at a time and no puking, but steady over the years.

And, for your consideration I added a coolant filter last year. The trip over Mount Eagle when I first puked was the first real hard pull after the filter installation. Could that be a cause?

I'm not opposed to paying for a repair but I am tired of paying the 100 bucks and getting no answer or a wrong answer, so my next move will be the degas tank. I'm also not opposed to either blocking the EGR or replacing them with Bullit Proof coolers but I would like to be sure it will solve the problem before I do it. And as always I thank y'all for the help and remain open for suggestions

 

Seems logical, but you said you tested for combustion gases in the coolant. Providing the test was accurate seems these items would be ruled out.

With that being said I would be surprised if it was a head gasket unless you have a early job-1 build mine is a 07-07 and the head gasket gave up the ghost around 65,000 miles but i was also towing alot in the 40-42 psi boost range. I follow alot of other boards and IMO the early if not all job-1 builds seem to see more HG issues then all the other build combined. I have confirmed this conclusion with our local dealer as well. In addition, they have also change the HG several times since the job-1 build not sure if theres a correlation between the two but none the less they have been updated.

As for the EGR cooler's, if budget is not an issue you cant go wrong with the Bullet proof coolers unless you wanna opt out for the delete. Other's disagree with me ,but i personaly feel the factory EGR coolers are a bomb waiting to go off with an expensive bill attached.

Hopefully the new degas bottle fixes your issue and you can be done with this, seems to be a little gremlin for you for some time!

 

Stanley,
Lot's of information already on your puking issue, but my .02 on the EGR Coolers, $1,200 on Bullet Proof coolers or $120.00 on EGR block off plates and coolant block off. I know you don't want to remove the coolers in case you decide to get a different ride that's why I mentioned just installing them with your coolers still on. It took me and my son a good 8 hours to delete mine but we took everything off, not just the coolers but also the cooler brackets, and installed new stat's which are a dream with those coolers out of the way. I think with just loosening everything up and putting plates in it shouldn't be such a project. Hope you get her worked out.