2001 F350 7.3L 4X4 Dually Crew Cab
Let me start by saying the radiator blew while towing 14k/LBS - 40ft trailer and the engine ran pretty hot while I found a safe place to pull over.
And by pretty hot I mean it got into the red momentarily. Slowing down and slightly downgrade surfaces got it to cool to safe range but I did touch on red a couple times.
I was able to add water once it cooled and made it back to my shop with normal temps. No other problems.

Fast forward a few days... after changing the radiator and checking all fluids on cold start up the 7.3l ran rough and blew white smoke out of the exhaust. This only lasted a minute or less
with a little RPM and warm up everything cleared that the motor runs normal.

Then yesterday another possible clue: the "Water In Fuel" light came on. I had never seen it before and didn't even know it was there! I've owned this truck 250k and 18 years.

This morning: Truck started and ran normal (no smoke and no rough idle) but i did see the "Water in Fuel" come on momentarily two times on my short [1.1 mile] commute

I thought the smoke and rough idle were glow plug related (still have the original glow-plugs and injectors) because it clears so fast. But is the water in the fuel light related? or are these two separate issues?

 

Generally white smoke means water/antifreeze.

Glow plugs during the summer/warmer weather do minimal heating of the cylinders to start engine. Water in fuel usually indicated there is water in the bottom of the fuel filter. Have you drained the fuel filter lately? The glow plugs and WIF are not related.

If you do have a water leak into one of the cylinders. If it gets worse, you could hydro-lock the engine do such damage as breaking piston, bending vales, pushrods and/or bending a rod to name a few.

Blue smoke is oil.
Black smoke is fuel.

 

Ok. So I should definitely start with a compression test

 

You can do a pressure test of the cooling system. Pressurize the system and see if it leaks down and at what rate if it leaks.

Check the overflow tank for bubbles with the engine running.

Have up checked the oil to see if water in the oil?

 

No water in the oil. Checked.
I do have a cooling system pressure tester. You're right thats a great place to start. Just ordered the adapter
for the threaded degas bottle cap on my truck. Will have it tonight.

 

Have you drained the fuel/water separator? It's free, easy and quick, and it is what the manual says to do if the light comes on.

Shut engine off, open valve to fuel/water separator, when clean fuel runs out instead of water, shut valve, cycle key to on, wait for the pump to refill the filter bowl and then start the truck.

 

Yup, white smoke is water. I also work on boats and we see a fair amount of white smoke. The over heat is a potentially bad tell-tale so keep an eye for milky oil. Anything from blown head gasket to cracked block. Keep your fingers crossed it's water in the fuel. Forgot to mention, water/AF usually smells like antifreeze so keep your nose working.

 

On a diesel white smoke during startup can also be raw unburned fuel. It important to determine if its fuel or coolant.

 

I agree it can be raw fuel during winter with bad glow plugs, but this time of the year, being summer, i have my doubts on raw unburned fuel.

 

I've only seen pure white unburned fuel smoke during startup due to raw fuel when it was cold out. I didn't plug in a semi truck because it was 60 when I parked it in northern Ohio, then when I came back it was down to 10 (And semis don't have glow plugs). It cranked for a good 30 or 40 seconds before the first cylinder finally lit off, and probably another 15 seconds before it was firing enough cylinders to stay running on its own. It was probably another 30 seconds before all 6 cylinders were firing, and there was tons of white smoke until all 6 cylinders started firing.

The point is if you have a direct injection diesel engine (rather than a precombustion / indirect injection diesel engine), as long as it's warm out it's not going to be dumping raw unburned fuel out the exhaust whether or not the glowplugs are working. An IDI with bad glowplugs will do it whether it's warm or cold out, but not a PowerStroke during warm weather.

Finally, the radiator blowing was probably a symptom of the problem rather than the actual problem. Think of it - you were within the rated limit for your truck's abilities, and the radiator burst. Most likely, the head gasket blew (or the head cracked), sending excess pressure into the radiator, and then the radiator blew. There's not many other ways to get enough pressure into one fast enoough to pop it. The cap should have opened and relieved pressure and any excess antifreeze long before there was enough pressure in the radiator for it to burst under any normal operating conditions.

I had a newer semi (than the one in the first story) with a cracked head - same exact symptoms you're describing, although it never popped the radiator. White smoke on cold startup during warm weather, and I'm amazed the radiator didn't crack because when I opened the hood the expansion tank was swollen like an overfilled balloon and water was actively spraying from the overflow, but after 10 or 20 seconds the head would expand enough to close the crack and the truck became driveable again. (The idiots at the company I work for kept saying they didn't see anything wrong with it because it wasn't doing it after it was warm, which was when they would come look at it... $20,000 repair bill and two weeks to repair it and Detroit Diesel refused to cover it under warranty because they said it was obvious that it wasn't repaired when it first broke - totally different story though).

 

OK Update:

Passed the cooling system pressure test. It held 16psi for more than 15 minutes. A very good sign the heads and head gasket are ok.

Drained the water from the main filter with the yellow lever on the back of the bowl. No more WIF light and have not had rough starts or white smoke.

I think we're good! I'll be pulling the 14k camper again soon so we shall see!! lol!

 

I'm very happy to hear you passed a pressure test.
Replace the radiator cap, if you haven't already. It should open long before you have enough pressure to pop the radiator.

The other possible way you're getting water in the fuel is if you filled up with contaminated fuel where the fuel had been in the tank long enough for condensation to put water into it. if that's the case, be on the look out for the light to come on again, and again until all the water from the contaminated tank is eventually purged from the system.

 

 

I did replace the degas bottle cap when I replaced the radiator. I actually think was all the result of the fuel additive I used - Howes diesel treatment actually sending water from the tank to the water separator.
Howe's seems to be especially good at quieting the injectors on a 7.3L but I think the emulsification properties actually sent water to the filter.

I believe the radiator failed because it was the original radiator and has served me well for 250,000 miles