Just to kind of update this. I've been home a couple weeks now and had time and a shop to work in. I started another thread on the coolant but here is a quick update. Oil sample sent, results, no coolant in oil, Bought a kit and did the block test, no exhaust gas in coolant (I don't believe it, I think I should have run the truck for a while longer before I did the test). Found a large amount of coolant residue under and behind horizontal EGR cooler. Tightened a loose hose clamp at the back of horizontal EGR. I was tickled thinking I had found the external leak. But the cooling system will still not hold 16 PSI, it will over 5 or 6 hours drop down to 13 to 14 PSI. It went down a lot faster until I tightened the hose clamp. And, with truck running at idle coolant system pressure will rise to at least 19 PSI. I shut it down then. Tomorrow I take the truck to the Ford dealer to see what they think.

There is some sort of internal leak making the pressure rise. When the pressure got high enough it leaked where the hose was loose and also puked out the 16 PSI degas cap. So, is it an internal leak in the EGR or a failed head gasket? I'm now thinking it has to be one or the other. And of course I'm hoping it's the EGR, the HG repair is very expensive. When I know, I'll post it up on here and on the other thread I started.

 

6.4 cooling system issues can be evasive.
I've noticed several times where guys start replacing stuff but never find out the original cause.

 

Stanley, I sure as hell hope it is not a head gasket! What does the inside of your tailpipes look like? As small of a leak as it is though, they may not be stained. Just a quick question, do you have the EGR valve that the coolant runs through, or do you have the newer style that bypasses it? Just wondering if it could somehow be bad and allowing a pressure difference. I know it SHOULD be a closed system..but....

 

Well, I'm happy and embarrased at the same time. Dropped the truck off at the dealer Monday. Picked it up yesterday. So here is the deal, I had two external leaks. The one at the EGR hose which when I corrected it made the pressure hold almost at 16 PSI, but not quite. Then another the tech found that was a clamp at the coolant filter which I had checked several times before but not very well I guess. just to be sure I put the pressure tester back on this morning and it has held at 16PSI all day. I don't know if the second leak even leaked when I was on the road but it did leak last week after I closed the EGR hose leak.

OK, so the leaks on the road were making the coolant get low and reducing the pressure in the system, the reduced pressure was lowering the boiling point and the coolant was boiling and that caused the puking.

I think because the superduty EGR coolers have such a bad reputation (based mostly on the 6.0L) I was way too quick to suspect them. Even after I found the loose hose and tightened it, when the system would not hold pressure rather than suspect another external leak i was too quick to suspect an internal leak. So, i didn't even look for one.

I'm glad it is over, I learned a lot and I'm just a little ashamed that I had to spend a hundred dollars for someone else to find the leak and tighten the clamp. Oh well, it could have been much worse.

 

in the end it was a good outcome save a few bucks and some well da moments.

Imho if you take care of your coolant and the level I think the coolers are fine.

It is when you go to messing with them that you can have issues.

You got a coolant filter on that thing?

 

Thanks for the update Stanley, when I get home some reps on your way, good information.

 

You got a coolant filter on that thing?[/QUOTE]



Oh yes I do. Thats where he found the second leak. It wasn't much of one, just enough to let the pressure drop down to 14 PSI over night.

 

I added a coolant additive from ford.Seems the 6.4 is prone to cavitation,more so than the 6.0 Hope u find the problem,,,,

 

Kinda disapeared, been busy. glad you got things fixed stanley and I'm glad I paid attention to this forum as well.. lots of good info.

-josh

 

It's a bit more involved than that. There is a letter in the tech folder at the front of the forum. What you added was SCA (silacate coolant additive) I think. I guess the dealer checked the nitrate level and told you to add it, right? Anyway, read the letter or if you don't find it reply on here and someone will post it up. The deal is that the coolant should be checked for nitrate level on a 20,000 mile schedule. I do mine each time I change the fuel filters which is 10,000. The test is done with test strips you can get from a number of on line sources. I get mine from Acustrips.com. It is a very easy test to do and takes about 3 minutes. Depending on the results of the test you either, do nothing, add SCA or flush and refill the system. Failure to maintain the nitrate level will make the coolant prone to cavitation which eats holes in some engine cover which in turn costs a bunch to replace. Hope this is helpful.

 

Stanley, I talked to Tracey on Monday after leaving work. He wanted to know if I'd heard anything from you about your trip. I gave a run down and he was glad the tranny did as you expected. He just told me to tell you hello.

 

Hey thanks, I've been meaning to call him.