Jump to content

Fuel/Coolant Intermix

Rate this topic


Recommended Posts

Hey Bruce, do you happen to have a cutaway photo of a 7.3L cylinder head assembly similar to the one you posted for the 6.0L? If so, do you mind posting it? I got an E-series here that just got dropped off by a small used vehicle shop. It's been ages since I've wrenched on any 7.3L so I'm a little rusty on the diag processes. Being a retail issue, I want this to have a ZERO probability for unforseen circumstances or a comeback. I'm pretty sure that on these, the cup(s) will usually be the culprit for fuel being introduced to coolant, unlike a 6.0L. I'm supposed to remove all eight injectors out and pressurize the cooling system and find the offending cylinder with the cracked cup, correct? Failing this, it's cylinder head(s) time? Sorry if it seems like a dumb question, but I got about four 6.0Ls on the go right now for major repairs as I post this, so I'm getting a little backed up. Thanks in advance.

Link to comment
Share on other sites

When I get a 7.3 Econoline with fuel in the coolant, I don't waste too much time diagnosing in chassis. I just quote to pull both heads and replace all 8 cups.

That's exactly what I did. So you're saying I need to add eight cups to the quote? New heads don't come with cups already pressed in?
Link to comment
Share on other sites

Yes, yes, yes, and thanks, Keith.

 

PS: I wouldn't pull the heads. I can't remember doing this task, but I'm pretty sure it can be done in the chassis with heads on. I remember one of my friends telling me the procedure: Use the tool to thread the cups, use the puller tool with a bolt through a large socket or round sleeve sitting on top of the head, and into the puller tool. Tightening the bolt into the removal tool will suck the injector cup out and into the socket, with minimal clearance needed above the head. You may have to drop the motor mounts or roll the engine, but that's easier than pulling heads. IIRC, I don't remember him doing anything with the mounts.......

 

 

Good Luck!

 

 

/forums/images/%%GRAEMLIN_URL%%/grin.gif

Link to comment
Share on other sites

A little dab of dielectric silicone will hold a coin(a dime if memory serves correctly)down in the bottom of the cup to plug the hole so no filings go in the cylinder. /forums/images/%%GRAEMLIN_URL%%/readthis.gif

Link to comment
Share on other sites

  • 1 month later...

Hey,I wonder of anyone has seen where the lower o-ring on all but one of the injectos has been eaten away... Posted Image

I got one in today,a 99 F350 with 74K,that has fuel in the coolant resevoir.Pulled all 8 injectors,and #2 cylinder is the only one that didn't have a chewed up bottom o-ring.All other upper o-rings look fine,and the center part of the injectors are discolored,probably from coolant intrusion.

The customer later informed us he's been adding marvel mystery oil to fuel tank...would that cause the o-rings to break down? I dont see any leaks at the injector cups as of yet,but the fuel has to get in the coolant through either the cups or head castings,right? Posted Image

Link to comment
Share on other sites

There's three o-rings, and you're talking about the lowest one, right? No, I haven't seen any problems with a set of the lower rings, usually the center and upper o-rings are damaged by HPOP pulsations. On occasion I see the lower o-ring damaged by a loose injector (leaking combustion) but not on a set.

 

Fuel in the coolant is almost always injector sleeves. Put a set of sleeves and o-rings in it and you'll be fine.

 

Good Luck!

 

Posted Image

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...