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Discussion Starter #1
Sent my injectors to full force to have them flow tested after my fass pump fuse blew and I ran the truck with no fuel pressure before noticing. They got back to me and said there was rust on the injectors found and coolant. Said I have either a head issue or cup issue. The current heads where replaced with some re-done heads that were magnafluxed, oringed etc.. before we installed them with head studs. That was about 30k miles ago. That said, I know these heads are prone to cracking but before I get too crazy and yank the heads, I wanted to get some other opinions. Is there a situation where multiple injectors would have rust on them from bad injector cups? That just seems a little crazy to me.

Thanks for your time in review.

Ken
 

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Any fuel in the coolant (it should float on top in the degas bottle)?

Cups just don't fail very often. Cracks in the heads are more common. What year model truck?
 

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Actually cracked cylinder heads on 6.0L is not a pattern failure at all and I have never seen COOLANT cause rust. Defined by it's very purpose, one of the main functions of coolant is to prevent corrosion. Right? Also, if you had a cracked cylinder head or injector cup you would indeed have fuel in the coolant. Cross mixing always occurs. Surface rust on fuel injectors is not uncommon by examining the one's I have removed from engines over the years. This concern is more common on trucks with aft-axle steel tanks due to the rusting issues but all Super Duties show it. It's water suspended in the fuel that causes it. I am sure that your your FASS system has not been installed for the entire life of the truck ot the injectors... or does this raise the question of the effectiveness of the system? To be honest, from what I have read, to removing suspended water requires the use of a centrifuge or a coalescent filter... and the ones found on motor vehicles still require further assistance to be sufficiently effective. That assistance comes in the form of fuel additives that cause the suspended water molecules (that are too small to be filtered out) to stick together and form larger droplets that CAN be filtered out.

Here is the fun part. You said "INJECTORS" not injector. You raised the question. If this was cased by coolant for example, and it was the result of an injector cup or crack in the head localized to one injector you should expect the rust to be most likely, localized to that injector. Though you did not specify how many had rust on them, multiple injectors indicates water in the fuel. Without question in my mind. FASS system aside, at some point those injectors were exposed to suspended water in the fuel in my professional opinion.
 

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Might also post up where the re-manned heads came from (and what model year engine). And to ford-doctor's point, was it all the injectors or just a couple? And, on which cylinders?

Also - what coolant has been used and have you ever run it on straight water (or a low antifreeze concentration). A recent thread on another forum (from a European shop owner) shows quite a bit of rust in the system (using an unconventional coolant)
 

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Discussion Starter #5
Thank you both for your insights. Definitely have me thinking now.. Apologize for not adding more detail in the initial post.

I've updated my signature with the truck detail in reference. Pls note this truck in indeed a C&C.
  1. I don't smell or feel diesel in the degas. (I know what to look for there as that's why the heads were replaced to the current)
  2. Coolant is Zerex Heavy Duty Extended Life formula at a 50/50 with distilled and been using even before the heads were replaced. Was flushed and refilled with change of heads.
  3. FASS 165 system was installed at the time of head swap.
Ford_doctor really got me thinking and something very notable.. I had a 100 gal auxiliary steel tank in the bed that fed a smaller mid-ship aux steel tank. I had a rust problem with that large Aux tank and eventually removed it after loosing the rust battle with it. It was installed for a small window of time but for sure 700-1000 gals were run through it for a trip from Phoenix to Miami towing 20k on the way back. Also, this truck is a C&C and had a steel after axle fuel tank which has since been replaced with a plastic tank. I still have the mid-ship steel tank which seems likely needs to be removed also.

Also of importance, I'd like to highlight the chain of events that led up to me pulling the injectors. My Fass fuel pump fuse had blown and I didn't notice. I was driving less than a mile from the house and the truck started running really ruff and blowing lots of smoke. I parked it and had it towed home. Once it was home, it was really hard to start and had an initial rough idle. It seemed to smooth out almost completely but intermittent would start idling rough again. Decided to pull the injectors and then sent them for flow test at Full Force.

They called me and essentially conveyed I must have cup issues or possible head problems. Not much else was conveyed but they did send me and email with these attached pictures.


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Just a few things to to inspect to help confirm if you actually do have a problem with suspended water or rust contamination. Remove the secondary fuel filter (engine mounted) and inspect the bottom of the housing. Look for rust/dirt colored debris and corrosion of the aluminum housing. With long term water in fuel concerns it's usually the first place you will find confirmation. Removing fuel line banjo bolts will also reveal water in fuel issues as they will show surface corrosion when exposed. One of the first places I look is in the primary filter housing - rust will collect in the water separator, filter housing and in the filter cap and commonly has the appearance of coffee grounds. I have also come to the conclusion that rusted fuel tanks that remain undetected long term will break down the rust as vehicle motion agitates the fuel in the tank breaking it down into particles smaller than 4 microns allowing it to pass the primary and secondary filters. I realize you now have a pre-filtration system but it's important to mention, just in case and for the benefit of anyone else reading this thread without an add-on pre-filter system which represents most truck owners.
 

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Discussion Starter #7
Just a few things to to inspect to help confirm if you actually do have a problem with suspended water or rust contamination. Remove the secondary fuel filter (engine mounted) and inspect the bottom of the housing. Look for rust/dirt colored debris and corrosion of the aluminum housing. With long term water in fuel concerns it's usually the first place you will find confirmation. Removing fuel line banjo bolts will also reveal water in fuel issues as they will show surface corrosion when exposed. One of the first places I look is in the primary filter housing - rust will collect in the water separator, filter housing and in the filter cap and commonly has the appearance of coffee grounds. I have also come to the conclusion that rusted fuel tanks that remain undetected long term will break down the rust as vehicle motion agitates the fuel in the tank breaking it down into particles smaller than 4 microns allowing it to pass the primary and secondary filters. I realize you now have a pre-filtration system but it's important to mention, just in case and for the benefit of anyone else reading this thread without an add-on pre-filter system which represents most truck owners.
Thanks for the response. I pulled the cap front my secondary fuel filter and while it looks very clean at the basin, when I set the cap & filter on the fan shroud, what leaked out of it was clearly water. I really think this is a case of me not maintaining the water draining.
157387
 

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That housing looks great though! I would not suspect any long term water in fuel or contamination issues from looking at that. Some of the housings I see look horrid.
 

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I was able to get a little more insight from Full Force regarding the injectors. They told me "Our fuel shop told me they actually installed four injectors into the flow bench to begin with and as soon as they turned on the machine it looked like a milkshake with the fuel in the beakers". This is supposedly due to coolant being in the injectors. This has me perplexed as to how I should move forward. There isn't a trace of fuel in my degas so how could coolant get into the injectors since fuel pressure is more than the coolant? I'm also confused as to how water could get between the injector in the sleeve to rust the injector body without the head being cracked?

Thank you!
Ken
 

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You can see the beads of water in almost every picture -- especially the fuel bowl pic -- the rust on the injectors is from water standing in the rails
 

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This has me perplexed as to how I should move forward. There isn't a trace of fuel in my degas so how could coolant get into the injectors since fuel pressure is more than the coolant? I'm also confused as to how water could get between the injector in the sleeve to rust the injector body without the head being cracked?
After shutting down the engine and fuel pressure in the rails bleeds down. At full operating temperature the cooling system is still under pressure until it cools. The lack of cross contamination is puzzling. Don't forget that his is a 6.0L and the fuel rail is cast into cylinder head. An internal crack can cause this, it's not limited to the cups.
 

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Fuel usually goes into the cooling system, if there is a head crack because of the higher pressure and the longer time period the pressures are different -- coolant by it's self would not corrode the metal -- plain water would tho because of the acidic properties picked up from the fuel additives -- test the ph to be sure
 

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Discussion Starter #13
thanks for the responses. I'm leaning to put a new set of injectors in and roll the dice. Keep you all posted.
 
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