blown99 Posted September 9, 2014 Share Posted September 9, 2014 Truck is an 04. About 3 months ago I did a set of head gaskets on this truck. Sent the heads out to be machined, installed new cups and guide seals. Came in today for something unrelated, popped the hood and found the fuel in the coolant. With the truck hot, I pressurized the fuel lines going to the each individual head. I was unable to isolate which head it was as the coolant level did not rise, no bubbles nothing. Customer stated that he was taking about a gallon of coolant out every couple of weeks so it is a small leak. Has anyone ever seen a cup actually cause this concern? I am looking at heads I have on the shelf and see no way that it could happen. Is there another method of isolating which head may be cracked? Removing the injectors and spraying them with soapy water and pressurizing the cooling system does not seem like a worthy diag when the cups don't even see fuel. Quote Link to comment Share on other sites More sharing options...
Matt Saunoras Posted September 9, 2014 Share Posted September 9, 2014 The cups don't see fuel but the crack above the cup does. I'll admit I haven't been able to find every cracked head by soaping the injector bores but I have found a few. Since you've already done headgaskets it would be best to find which head is the culprit in the chassis. Otherwise you're looking at removing both heads and pressurizing the fuel rail with the head upside down and the water jackets filled. The last set I did it took over 100psi of air to find which head was cracked. You need to make sure all of the fuel is out of the rail too. The smaller the leak the harder it will be to find. Also if you do resort to pressurizing the cooling system make sure to pull both block drains to clear the heads of any coolant. Quote Link to comment Share on other sites More sharing options...
leavnon3rd Posted September 9, 2014 Share Posted September 9, 2014 Not a normal test procedure, but what about blocking off fuel supply to one head a time and using moderately above normal fuel pressure to see if the coolant level rises? Maybe even block one head off and deadhead the return and let the fhcm pump on its own ? Quote Link to comment Share on other sites More sharing options...
Buddy_M Posted September 9, 2014 Share Posted September 9, 2014 I've always been successful in pressuring the cooling system up to 18-20lbs(sometimes I'll push a lil higher if a stubborn leak) and disconnect both fuel feed lines at the filter and watch for which one drips out under pressure. It may also help to plug the block heater in also if it doesn't leak cold. Quote Link to comment Share on other sites More sharing options...
Steve Mutter Posted September 10, 2014 Share Posted September 10, 2014 Bullet proof diesel has some sort of fix for this that does not involve removing the heads. Check it out, http://www.bulletproofdiesel.com/BPD_Cylinder_Head_Repair_Tool_Ford_6_0L_p/cylinder-head-repair-tool.htm Quote Link to comment Share on other sites More sharing options...
jimmy57 Posted September 10, 2014 Share Posted September 10, 2014 The Bulletproof deal doesn't have enough explanation. I could see a revised full bore slleve with a cut relief slot for fuel inlet being a fix. The Bulletproof tool seems to not be that. My personal truck has fuel into coolant issues. I have not been able to pinpoint which head after a few fuel bore pressure tests. The machine shop we use can get me American made bare heads for around $400 each. I'm going that route. This truck blew gaskets and I nursed it home while pulling a 30,000 pound trailer plus hay load. It took 10 gallons to get me the 100 miles home. The heads were surfaced 0.002" each and no cracks found. My worry is that they both got hot and one is cracked but the risk is great the other could crack so do both and be done. Quote Link to comment Share on other sites More sharing options...
Matt Saunoras Posted September 10, 2014 Share Posted September 10, 2014 I am friends with a guy who's in good with bulletproof diesel. Bulletproof insists this is a permanent fix but if another injector bore were to crack the process would have to be repeated. It is some kind of epoxy injected into the crack. Quote Link to comment Share on other sites More sharing options...
blown99 Posted September 14, 2014 Author Share Posted September 14, 2014 I ended up pressurizing each bank with 120 psi into the fuel rail. Set the coolant level to max. I could see the coolant level dribble over the fill neck on the passenger side for about an hour. After an hour, the air pressure finally pushed the fuel through the crack and I was able to see the air bubbles. Found #5 to have a pin hole on the exhaust side of the injector bore. I ended up machining a good used head and replacing it. Quote Link to comment Share on other sites More sharing options...
Matt Saunoras Posted September 14, 2014 Share Posted September 14, 2014 Over half the ones I've seen were #5 cylinder. Quote Link to comment Share on other sites More sharing options...
Matt Saunoras Posted September 18, 2014 Share Posted September 18, 2014 trim.JdCYb0.MOV #3 cylinder in an 07 F-550 I'm working on Not sure if the video will work or not Quote Link to comment Share on other sites More sharing options...
jimmy57 Posted September 18, 2014 Share Posted September 18, 2014 It is not clear if that is a crack or a sleeve leak. Which is it? Quote Link to comment Share on other sites More sharing options...
Matt Saunoras Posted September 18, 2014 Share Posted September 18, 2014 Crack for sure. Hard to tell but the leak is up higher in the bore than the cup.Like Mark said look for the crack on the exhaust side of the bore also. What I do to get the foamy soap in the right spot is to cut a 3/4" wide strip off a scotch-brite pad and use that as an applicator. Quote Link to comment Share on other sites More sharing options...
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