Ok..... my apologies for the novel, but ive got plenty of back story to fill in some gaps....

Three weeks ago..... i was driving to work and about a mile from work i started smelling coolant. Upon arrival at work I get out and turn and look to see fluid pouring from the engine. I pop the hood and the hot fluid is pouring out on top of engine from the heater hose which has a core shutoff valve which i installed about 10 yrs ago. Water pouring from the seams of the valve and some holes that are in the housing of it. Ruptured diaphragm. I figure OK, well this sux, but at least it waited until i got to work, and its pretty easy to figure, voila, thats it..... I remove the cap from the degas bottle and it was tighter than usual to unscrew, upon removal i noticed the bottle was indeed emtpy, but had lots of trash/debris/scum on the inside. I tried to put cap back on but would only get a half thread and it would start clicking and wouldnt tighten up any more. I had a coworker take me to parts house at lunch and i purchased some heater hose, a new degas bottle/cap, and some fluid. That evening i removed the shutoff valve, inserted a pipe nipple in its place, clamped it down, filled with fluid. i took the cap from the new bottle and put on the old bottle and screwed down. Started up and ran in parking lot for 10-15 min, no issues. I drive home with no issues.

One week later: I drive it about a week with the pipe nipple in place, i started noticing wet spots under truck in parking lot before going home. Cant really see where coming from. About two days after initially noticing, i was able to positively identify it as the water pump leaking out of the weep hole. I had a new water pump in my garage from clay that ive had a couple years when i thought i had a water pump issue but didnt. So I make plans for last weekend to tackle the water pump replacement. I also replaced the OEM oil pump with the Melling thats been sitting a drawer for a few yrs as well as replace the harmonic balancer with the Fluidampr that has also been laying around for quite some time. Figure half of that job was already done with the other stuff out of way so i did those as well. Anyway, replaced new water pump, reused my old 203* thermostat that looked and felt fine (about 4-5 yrs old), replaced the older degas bottle with the new one i just bought with the new cap. New lower and upper radiator hoses as well. I drove around the block (4-5 miles) and everything checked out fine. So this week I started driving to work again with it.

Monday: I drive to work and everything is fine. I got to truck at lunchtime and notice a wet spot under the passenger side front bumper. I pop hood and see that it appeared coolant had spewed out of cap onto passenger side battery and under the hood. Degas bottle about half full. I drive to lunch no issue. I drive home and pop hood again and notice that coolant had again spewed out cap and degas bottle is empty. Unscrew cap, slight pressure release, not much. I fill with fresh fluid.

Tuesday: Same thing. To work is fine. Lunchtime there is wet spot, half bottle. On drive home I start hearing some noise inside the cab, not sure what it is, but sounded like a card stuck in a bicycle spoke rim. Lasted about 5-10 secs, did this twice. I have a large bridge to cross on my commute that goes over our local ship channel, its about 180 ft tall, closest thing we have to hills/mtns in these parts). Traffice was backed up that day and i was only going about 15-20 mph when crossing this bridge. I noticed that my OEM temp gauage bobbled and increased to near the hot range on the gauge , this is unusual because in the 10 yrs i have owned this truck the temp gauge has held rock steady forever, it has NEVER gotten anywhere near the hot range, always stays in middle. After crossing the bridge and traffic sped up the temps came down to normal. I am thinking it is the cheap chinese knockoff aftermarket parts and the cap is a piece of crap and wont seal. I stop at a different parts house on way home and buy another cap. This cap is not the click to tighten style cap, but a cap that will screw down tight and not click. I get home and bottle is empty. Unscrew cap, little to no pressure build up. I am out of fluid now and just fill with water.

Wednesday: I bring a gallon jug of water with me to work (havent done that in about 20 yrs) , upon arrival at work i notice that i have lost almost all of degas bottle.I had wrapped some paper towels around cap to see if it was the cap or maybe a crack in bottle, the towels were sopping wet around the cap. I am thinking it is the cheap chinese knockoff aftermarket parts again that are leaking. Ive learned this lesson before about aftermarket and OEM parts. WHile at work i order a new degas bottle and cap from Clay and have 2 day UPS shipping. I fill with water before heading home. While driving home i hear the inside cab noise again about 20 min after i start driving and again about 20 min later. This time i really listen and it sounds like a coffee percolator. (water boiling). It must be the heater core if can hear it inside the cab. No wet spots in the cab, no coolant smell in the cab. I get home pop the hood, the degas bottle is about half full and i can hear more "percolating" in the upper radiator hose from thermostat to radiator. I unscrew cap and hear no pressure release. I go to remove cap and fill a suction on the cap. A vacuum has been created and it sucks the gasket inside the cap out upon removal. Once air was allowed, degas bottle quickly drained empty. I filled back with water.

Thursday: Take two jugs of water with me this time. Same story. Wet spot under truck, empty degas bottle. Fill up, drive home. More percolating noises, but temp gauge remains in normal range until traversing the bridge again, then back to normal. After talking it over with coworkers/neighbors thinking it might be the thermostat or trapped air in the system.

Today: The OEM degas bottle from Clay arrived today, I went and purchased a new thermostat from part house and fluids. I completely drain the system thru petcock and hose coming from bottom of degas bottle to bottom of radiator. I had left the thermostat housing open so that i could burp the system upon refilling. This worked just as i had hoped. While pouring fluid into the system could see it fill up inside thermo housing. And just as i suspected it started burping air that was in the system. I did this for some time until it quit burping and started overflowing. I installed the thermostat and upper radiator hose (around the belt hose, not thru the belt) but did not fasten to radiator. I fill until fluid comes out of top of radiator, then fasten the hose. Fill to level and tighten everything up. Crank in driveway, run on high idle for about 10-15 min to come up to temp, then take for a drive. I drove it around the block again (4-5 miles), upon arrival at home i decided to take it around the "larger" block, total trip about 12 miles. During this driving the temp gauge holds steady in the middle of operating range the whole time. I am driving it rather hard to put a load on the engine and get it to heat up. I am coming down the home stretch, get about 1/8th mile from my driveway and let out of throttle to coast home and slow down. Upon doing this the temp gauge spike into the red/hot range as i pulled in my driveway. It quickly cooled right back to normal upon parking. I get out and pop hood and sure enough the new OEM degas has also spewed from the cap just like the others. I unscrew cap, but this time it has pressure and threatens to spew like a volcano coming out of bottle. I screw the cap back on. The hoses are "precolating" again. This time i can see fluid going back into the degas bottle from the drivers side of it thru the little 3/8th hose on that end. I shut the valve off from the coolant filter to see if it coming from filter or radiator. It is coming from the radiator and percolating back into the degas bottle. It does this for several minutes. The system held pressure for quite some time. I tried to unscrew cap again and again almost got burned.

Im stumped as to what the hell is going on here....any help/insight is appreciated. To recap: radiator is two years old, new water pump, new fluids, new degas bottle, new hoses. Still boiling over and spewing out of cap. I have done this type of work before with no issues. First OEM waterpump change at 180k, now changing the parts house special at 169k. Same work as just performed and no issues. I have drained system for oil cooler, waterpumps, and radiator hoses in past with no issues. Why issues now? Saturday I think i will remove thermostat and drive around just in case there is air trapped and try to work it out. Also thinking about removing radiator and flip upside down and try flushing out, but the radiator is two years old and i dont think thats it, butttt..... What about the heater core? If all these years while driving with the core shut off during our summers for the colder ac, could there be something plugged in the heater core? I dont leave valve shut all the time, but it is shut most of the time. Has been working fine during winter. I am willing to listen to all suggestions.

For the FIRST time in the 10 yrs i have owned this truck, I dont trust it right now. Thats a sucky feeling. Especially after Ive been bragging on it over the years even with all the miles i have on her.

 

Sounds like a bit of a mess... Sorry to hear! Don't have much to offer. Just sticking around to learn

I'm looking into upgrading my transmission cooler, cleaning the Oil Cooler, and replacing my radiator for the hotter months.. I hope I don't run into anything like this!

 

If you want to eliminate the heater core from the equation, simply get two elbows and four clamps and a short piece of tube and make a loop from the water pump to the pass side outlet.

 

Damon,
Can you hear your fan clutch engage when the coolant temperature shows signs of heating up? It sounds like you aren't getting sufficient air flow through your radiator. It may be finally engaging when it is already too late.
Other than leaking, the heater core would offer nothing in the way of increased coolant temperature. If anything, it adds supplemental cooling and does nothing when plugged.

 

I would say no on hearing the fan clutch engaging. But thats a bit misleading i believe, as the amount of time that the gauge indicates that it is overheating isnt long at all, maybe a minute at most, according to the gauge because for the most part it is steady in the middle of operating range. I havent dont anything today because im still trying to think through what to do, but at my neighbors suggestion to rule out fan clutch, while engine was running i took a piece of stiff cardboard and tried to stop the fan while running. It didnt stop. Theory is that if the clutch was bad the fan would have stopped with the cardboard.

Talked it over with a buddy of mine who has a 6.0 and he seems to think it might be cracked injector cups. What are typical symptoms of cracked injector cups? Head gasket maybe? But if that was it , wouldnt i also have smoke and water in exhaust? I dunno, i hate to just throw money at changing parts without at least having some idea that may be the problem.

 

On second thought, the first time that something happened, the 3 wk ago item in my list above, I mention that i smelled coolant, but now that i think about it again, what i smelled first was fuel, diesel. I was thinking it was the fuel filter oring or dump valve again. But there was also a semi next to me and i thought that maybe it could have been him that i was smelling, but then when i was alone on the road i could still smell it. So, the very first event i did smell fuel before i smelled coolant. Then when i pulled up at work about a mile or two later, thats when i discovered my heater core shutoff valve had failed. Failed due to heat? Over pressure? Or exposure to diesel? Thats the $64,000 question..... Soooo...with that said... could i be looking at an injector cup job in my future? I havent smelled fuel in the coolant other than the first time though.

 

When my truck is hot and the clutch engages for the fan it sounds like an industrial leaf blower just started up. Either that or a jet is launching under the hood. With or without the windows up it is very noticeable. The only time I miss is is when I'm rocking out with the stereo cranked.

I also can hear the fan sometimes in the morning when she's just "waking up" as in leaving for work.

 

A buddy of mine lost an injector cup and the coolant bottle had a noticeable layer of diesel sitting in it completely separated from the coolant. I don't know if that's your issue...

 

yea, i know the sound it makes when engaged. I just dont recall hearing it for these events. Hell, ive rarely heard it over the years, just on occasion, but i know what it sounds like. I think i may have had some fuel in bottle the first time as there was some film inside the bottle. But ive changed bottles twice and cleaned everything up since then, so its hard to tell.

 

If you don't hear that thing roaring when you know the temps are up, you fan clutch is shot....or the sensor that tells it to get busy.....You can't miss it. When your truck is stone cold first thing in the morning, give the fan a spin. there should be resistance and it won't spin free. if it does, there's your sign.

 

And I'm pretty sure if your Cups were toast you'd find your Degas bottle turned black pretty quick with Oil/Diesel or both inside, Take a sniff!

 

yea, i gave the fan a spin, there is resistance, but i seem to recall more resistance when i changed it about 2 yrs ago. But i did change it with an oreilly special. It hope its as simple as that, thats cheap enough to throw money at and hope it works. It kinda makes sense since it happens after long runs or loaded runs when i slow down (less air flow). Initial event had the inside of the bottle fithy with trash/debris. Ive slept too many times now to recall exactly how it appeared but it was nasty. It could have been just scale knocked loose after overheating. I still see some trash in coolant in bottle, but best i can tell i dont see or smell any fuel in it. It could be as simple as fan clutch, but just two years into this one first guess would be no, but with these aftermarket items the quality is crappy, i know, i should stick to my own adage and get OEM as much as possible, but sometimes that isnt as convenient.

Thanks for everyones input. It is appreciated.

 

Yeah, I embraced the Suck, when my clutch went intermittent first for awhile, then did full-on Tit's up on the Grapevine in Cali, towing a 31' 5ver, with dogs and kids.....(sigh) now I just want to forget.......

 

...or the sensor that tells it to get busy...

There is no sensor. The 7.3 fan clutch is all mechanical. I do agree however, it sounds like the fan clutch. Slowing down on bridge and other places seems to be where it heats up. As long as you are moving at a good speed the clutch is not needed but in traffic or creeping along is when the clutch engages. When mine went out the first thing I noticed was the AC quit working when idling. Check that if it is hot where you are.

 

I have a quick question. So, one of the the hoses to the heater core comes from the top of the water pump and the other comes from the PS head. A family member didn't believe the Ranger valve mod would make any difference in A/C temp so he wrapped one of the hoses with a rag and clamped it with a set of vice grips.

Well, the A/C did get colder; however, the EOT went up about 5-7 degees F.

First, does that make any logical sense? If so, could this simulate a clogged heater core and does anyone have a map of the water channels in the block and heads?