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Ok so as the title states I have coolant in my fuel bowl but dont have fuel in the coolant bottle. Truck is a 2000 powerstroke. the truck runs and drives great, could it be the injector cups or some other problem? the truck doesnt run hot or smoke except for start up when its trying to burn the coolant in the fuel. so what do you think?
 

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I didn't even know that was possible, without putting coolant in the fuel tank.....

On edit: I know this didn't help, but I can't fathom how coolant would get there any other way......
 

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I'm with fddriver2. Seems unlikely for coolant to get in the fuel system from the fuel rails. Fuel rails are at 50-60 psi, coolant is at 15 +/- psi, so even if an injector cup was seriously cracked it doesn't seem too likely.

I suppose with a lot of on-off operation, the coolant could get into the rail, and possibly back into the filter with a warm engine (15 psi coolant and zero psi fuel pressure). It'd have to expand back thru the rails and fuel lines to get to the filter, and if that happened, the fuel rails would be pretty much full of coolant, and I'd be surprised if it ran at all.

AFAIK, the injector cups are the only place that fuel and coolant are directly adjacent. I think that replacement injector cups are in your future. And I wouldn't be running too much coolant thru those injectors, or you may be replaceing them also.
 

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For over a year now I have been getting 30 - 60 seconds of white smoke along with what felt like a missing/fouled cylinder at cold start. But not every cold start, only after the truck sat for over 24 hours or if it was really cold (I live in California's central valley, so my cold isn't really cold). If I drove it every day it would start fine and in the heat of summer it started fine. I thought it was just a glow plug and since its never really cold, I put off the repair.
For some reason, two weeks ago, the symptoms quickly got progressively worse as we experienced a week or two of consistently freezing weather until one day I smoked out my entire neighborhood on cold start and ran awful for a couple minutes before clearing up. Then I started smelling the fuel in the cab. A couple days later I saw the top 1/3 of the coolant reservoir was diesel. My current theory is that a cracked injector cup was slowly leaking coolant into cylinder #7 while the truck sat and if left too long would accumulate enough to cause the smoke and fouled cylinder until it burned/pumped the coolant out. How does that sound?
At any rate, yesterday I finished up the injector cup replacement project by changing my fuel filters for good measure. That's when I found the fuel bowl had quite a bit of coolant in it! The pre-pump fuel filter didn't have any coolant it. I'm assuming this was a side affect of my cracked injector sleeves / cups. But you know what assuming makes you! Is there any thing else I should be checking?

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Ok so as the title states I have coolant in my fuel bowl but dont have fuel in the coolant bottle. Truck is a 2000 powerstroke. the truck runs and drives great, could it be the injector cups or some other problem? the truck doesnt run hot or smoke except for start up when its trying to burn the coolant in the fuel. so what do you think?
How do you know it's coolant? Diesel fuel can be quite green, just like some antifreeze. When you drain the fuel bowl into a glass container, do you get two distinct layers?
 

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I don't know about mbourland, but my coolant was red and layered underneath the diesel fuel. It was very easy to see through the diesel after it was all drained in a bowl.

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I wouldn't say the coolant was going directly into the cylinder. The coolant was probably pushing into the fuel rail after the truck was shut down, where the 16# pressure of the radiator easily overcame the 0psi fuel rail. As the crack got worse, the coolant backed up the fuel rail into the bowl. It ran rough while the coolant was being injected into the cylinders
 

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Coolant in fuel bowl

Hey folks, wondering if anyone has found a definite solution to the coolant in fuel bowl problem? As discussed, I see no way that coolant could get into the fuel bowl unless there is a cracked injector cup and the coolant is flowing back through the fuel rails after the truck is shut down and no pressure is on the fuel system but 16 PSI is still on the coolant.

My truck is a 2001 7.3L with the 6 speed manual. I was getting diesel fuel in my coolant reservoir and had the injector cups replaced. Now I seem to be getting a small amount of diesel still going into the coolant but there is also coolant in the fuel bowl. Short of having the fluid tested at a lab, I'm about as sure as you can be that it's coolant. It's green, separates from the diesel, and smells like coolant. I've also had the fuel tank dropped and cleaned so I know it's not bad fuel. I've been draining the fuel bowl before starting the truck and this helps it start without smoking excessively. I also open the coolant reservoir cap after shutting down to depressurize the system and that seems to lessen the amount of coolant in the fuel bowl at the next start. With these procedures applied, the truck runs well except the water in fuel light flashes intermittently - seems to be loosely associated with acceleration. I'm thinking perhaps I got a bad injector cup or one was not seated correctly when the job was done? The weird thing is it apparently passed a pressure test. Any inputs are appreciated!
 

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Fluids will go from high pressure to low pressure.

Normally the fuel pressure is much higher than the coolant, so fuel ends up in the coolant with faulty o-rings.

I suppose if your fuel pressure was lower than the coolant, but high enough for the engine to run, that you could end up with coolant in the fuel.
 

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I found your post online but when I registered for the site I couldn’t find your post....So I posted mine in hopes someone would help me. They linked this thread for me. So anyway I am having the same coolant in fuel problem you described. Can you shed any light on the subject?
 

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Injector O-rings or injector cups tend to be the culprit here. With the age of the 7.3L by this date, the O-rings should have been changed at least once, or you are at risk for a leak.
 

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My original post on another thread. Sorry I’m still trying to figure the forum out.

I thought I had bad fuel from a trip we took over the summer. Fuel filter had water in it every morning and with further investigation it was worse. Fuel in my coolant. Been reading a lot and talking to a few mechanics in my area. All said replace the cups. So I started the project. Did all the cups and sent off the injectors to be rebuilt while I had them out. All back together and runs great... but the water in fuel light is back on. I took a water jug and drained the fuel filter and sure enough coolant in it but fuel not in my coolant as of yet. I’m use the Delo ELC and it’s red. Any help is appreciated.
 

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How diligent were you when you cleaned the cup seating surface before installation? Did you use the recommended sealant and allow time to cure?
 

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I actually Got my phone to the back hard to see areas and took pics of how clean I got them. I thought they looked good. I also used the provided green lock tight from rosewood and it sat probably 24 or more hours.
 

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As I said constantly having water in fuel light and draining fuel bowl. Parked it out of frustration and ended up dropping my tank. The pic is what I poured out of my tank...and no nobody went and bought the Chevron elc and poured it in my tank. This is a real problem. Fuel back in my reservoir now too.
 

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The way to test for this as far as injector cups is concerned is to remove all 8 injectors and then pressurize the cooling system and inspect. The use of UV tracer dye is highly recommended. Add the recommended amount of dye for water based fluids and run the engine to full operating temperature to ensure complete dispersion before disassembly. When cooled If you have an injector cup leaking it will be very obvious. I have seen cracks in the injector bore near the top of the cup extending above the cup as well. If no dye is observed then a cracked cylinder head is suspect... almost assured actually. The only problem at that point is, which one?

I have always used Tracerline dye. It requires a special UV light and filter glasses to be able to see the dye. Google it and you should easily find inexpensive kits that come as a light with glasses and the dye will be separate. Be sure to obtain the correct dye for what you are testing - there is dye for oil based fluids and water based. FYI - The oil based dye may also be added to fuel to detect leaks in the fuel system.


The kit I mentioned is a UV flashlight and glasses. These work well and most technicians I work with use this as do I. You do not need an expensive high intensity lamp.

 

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Time to pull the injectors and inspect everything
 

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Ok so as the title states I have coolant in my fuel bowl but dont have fuel in the coolant bottle. Truck is a 2000 powerstroke. the truck runs and drives great, could it be the injector cups or some other problem? the truck doesnt run hot or smoke except for start up when its trying to burn the coolant in the fuel. so what do you think?
Do you have a fuel heater on your truck?
 
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