Fuel in the coolant on a 6.0L is almost always a cracked head. You would have to use the taller (aftermarket) cups to fix the leak (taller cups isolate the typical leak/crack area). The typical cylinders that crack are the middle 4 (3,5 and 4, 6).

It could happen if the (original) cup was cracked AND the lower injector o-ring was compromised - both on the same cylinder at the same time. If that were the case, it would most likely run rough and you would probably have an injector code. This scenario is not common.

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Most shops, when they have this, just replace the head. As Mark noted, some kits use a taller cup to seal that area, and kits that use a compound to go into the crack and seal it from what I’ve glanced. I’ve never done either and can’t say how well the compound works long-term.

The issue typically happens with the center two cylinders on the passenger side, which always has me wondering about coolant flow on that side. Some have had it on the driver's side, but that determination gets muddy with heads being removed during an HG repair.

This will seem off-the-wall, but what color is your oil dipstick handle?

 

Black

 

The truck ran fine full power, no shaking, idle smooth no sign of anything. Just a few days ago I want to do a irp relocation and some other mods, went to checking fluids to make sure everything was good. Saw black stuff in the coolant and was like wth, it wasn't a lot at the time but after a day or two of driving it started to get worst. Truck still ran like a dream, so I started to pull the engine down to prepare for my kit, did some research and found out I might have a cup issue or cracked heads. what have me confused is that there wasn't any blow back or over flow reservoir or any signs of preasure pushing into the coolant passage to say it a cracked head.Thats why I was going with the cup failing and needed to be change out. So the pictures are my injectors from the drivers side, the one injector with the heavy black stuff is cylinder 8 the clear jelly is 6 ad the other is 4 (which the pic with the cup is also 4)

 

Last injector image, typical of the fuel o-ring leaking into the bottom chamber, which should be dry. Unless someone used an excessive amount of oil on the injector during installation.

You will not get high compression gasses into the coolant system; that's not where the crack is.

 

Okay so just Replace both heads?

 

I would see what you have. I feel that some shops flip out for new heads as they don't want the uncertainty.

However, UFC Machine Shop in PA has a long history of supplying 6.0 rebuilt heads (o-ringed), and they put the long cups in every head they rework, with a lifetime warranty.

I would look to see your issue and if you want to try one of the repairs or go through the expense on new heads. Since I've never had to do this work, I can't say how successful it is.

Since your dipstick is black, you have 18mm heads unless these were gone through before.

The 20mm OE heads (2006.5+) were reinforced in the injector area to prevent cracking. However, if you hunt for 20mm heads in the aftermarket casting, it doesn't mean they were cast with the reinforcement. A supplier would only have to bore out the 18mm counterbore to 20mm, and some other drill and tap work to sell them as 20mm.

 

I think my fuel rubber rings are bad, most of them were peeling( the white ones). This was another reason I was thinking the cups.

 

P012f is for a clogged oil cooler.

Are you sure what is in the degas bottle is fuel, or is it just oil?

 

It smelt like fuel but when I drained the coolant out in a bucket and left it for a few hours, it had a white sheet of something above the coolant.

 

Sounds like fuel then, but very likely you have a plugged oil cooler also, maybe even a failed oil cooler.

 

Well I was doing the IPR kit anyway so that I wouldn't have that cooling issue. Now I got this extra crap going on.

 

Do you know if these injectors were ever worked on? When the injectors are loose, we often see issues with the o-rings.

 

Yes, they Guy I bought the truck from said they got the truck studded 5 years ago. The truck was seeping oil like crazy. Come to find out the valve cover bottom bolts I loosen by hand, the high pressure oil rail bolts some of the barley took any effort to loosen them. Basically they didnt take there time to go over their work to make sure everything was torque properly. There were more things and yes one of them was two of the injector hold down was tight but loosen with less effort than the others( i'm guessing oil was in the hold down and they tighten the bolt which gave a false torque). I just bought this truck two weeks ago and I think it was recently worked on, the engine was way to clean on the top end.

 

That one pic showed a lot of assembly lube on the injector tip -- so yeah, likely someone has been in there

Too much lube trapped in the lower part of the bore will fail the white oring, as the pressure from expansion of the excess lube has to go somewhere
I also think this is the cause of a leaking copper washer soon after an injector replacement

 

Cool, I bought a complete cup and o-ring kit, but im still not sure of the fuel in the coolant being just the cups.

 

What sometimes works to confirm oil vs. fuel is how easily the liquid absorbed by the paper towel ignites, the fuel, of course, being easier.

Attached is the old TSB for checking the issue in the injector bore while you have them pulled.

 

Fuel in the coolant is generally a cracked head, but can also come from a cup that has lost it's seal at the top sealing surface

Fuel will leave a brown sludge floating in the coolant bottle and have an "old turpentine" smell in the coolant bottle area

Yours is more black ? , then I would lean more towards oil
Leaking orings on the oil cooler can seep into the coolant if the weep holes are plugged

 

Weep hole.

 

Well today I did a water test to see if the cups were bad or the head, cycl 4,6,8 all have cracks the passenger side has no leaks so far after a hour of 20+ psi. So I ordered the head repair kit from Bullet Proof diesel.

 

Pictures and let us know how well it works as you proceed -- I have not used one of these , but have watched their vids

 

Unfortunately, that is the common side of the engine with the problem.

 

Unfortunately, that is the command side of the engine with the problem.

I have not opened the driver side valve cover once since I've owned the truck. Bought at 78K and now has 266K. I've had multiple issues on passenger side 1,3,5,7. Weird.

 

I have always thought heat plays quite a role in those failures, and like @TooManyToys mentioned before, that side of the engine is where the failure is most prevalent

Possible the coolant flow is not adequate on that side of the engine, and any over heat condition starts the scenario for cracks

 

I do think there is an issue over on that side. Other than it's typical on that side, what piqued my interest more was seeing the restrictors put into the 6.4 engine block. Both sides have orifice plates, but the driver's side is smaller, so more volume goes through the passenger side. The heads are interchangeable side to side, so there is no unique casting for the passenger side.

One of the people who had commented on one of my videos said he had a pickup bed full of passenger side heads with cracks.

This is just a SWAG because all R&D starts with a SAWG. Trying to figure out what may be different on the one side, it could be the movement of coolant out of the front cover through the water jackets. But as I was looking at the block water jackets with my borescope, the most significant difference on the passenger side is the block heating element. And it's positioned in a horizontal lay, so it has the most resistance to flow. Is that what they were trying to compensate for with the 6.4L block?

I don't know. I made a video about the possibility. I found a plug that would replace the heating element but must be modified to seal. I've got a twin channel thermocouple meter, and I can stick two surface thermocouple probes onto the exhaust ports of the front cover coming out of the heads to measure the relative temperatures of each. Someday.

Ideally, it would be drill and tap for thermocouples there, but I don't want to screw with the expensive and hard-to-find front cover, especially since mine is new.

As Kramer would say, it's out there.

And there may not be anything to it.


The crazy guy's video; let's cross over to the other side of the street.

 

Okay after some research and a few videos, I found out that this method has a low successful rate vs the extended cup. I also found a half inch hairline crack in cylinder 6 not including the leak in the picture.I i'm stuck between doing a head job on the truck or extended cup. To many crack to risk $700 on something with a low successful outcome.

 

My vote is to replace the head.

 

Quick question what size is the tool(tap) for the cup removal? second purchase and they can't seem to cut into the cup

 

I have a cup here on my desk, reads .723 inside diameter -- the 3/4 tap should make some threads, bear in mind the stainless will not cut very well since it is so thin

You may need to cut the tap off some to get less of the taper involved , since the bore of the cup is short, it may not allow the full diameter of the tap to cut

 

And stainless is curmudgeon material; it's abrasive and cutting resistant.

 

I think the end taper is causing a lot of the problems -- there is only about 3/4 " depth to the cup , and that is nearly the amount of taper on the tap

Start the threads with a regular tap, but finish with a bottom tap -- or cut the tip on a regular tap some

 

I replaced #5 injector cup with accurate diesels product and it's held for 10k plus miles. I made the mistake of purchasing the ebay cup and tool the first go around and destroyed the threads on a new injector because they poorly machined the threads. The Ebay tap is complete garbage and will just strip the teeth. You have to press pretty hard on the tap to get it to bite. Make sure you go as far down as you can or you'll pull the threads when trying to remove the cup. I replaced all the cups on the passenger side with new OEM cups and one accurate diesel cup. Used the green loctite for the oem cups and a thick gray sealent that Tim provided with his cup.

 

The ebay cup, are you referring to the extended cup or the regular cup? I just purchase 6 ext cups from ebay