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Discussion Starter · #1 ·
I'm troubleshooting some running hot under load and coolant loss issues, and wanted a few opinions on some smoke @ startup. Initial white poof followed by blue, then clears up. Never any visible smoke, etc while driving.




Oil analysis has always come back great. No clear contamination in degas. Lost about a pint of coolant pulling 14,000# +- 300miles in last 2 trips. Deleted, studded by PO. Power and overall running is good, tops out 26-28psi boost. I've got a coolant pressure gauge that's not exceptionally accurate but shows I re-build about 2psi after bleeding off from 13psi, unloaded, I haven't done this with 5th wheel on it.

Driving hard under load coolant pressure is 15-18psi on the Auber gauge, which is in bounds of reality. Doesn't "spike" more than 1psi or so. Slowly builds and slowly comes back.

Next step is to pressurize it cold and look really any leaks, but there's no crust or buildup that I've seen so I'm fairly confident coolant is being burned. Will also do a contribution test in the next couple weeks to get a sense of injector health.

I'm leaning to a cracked head as likely culprit, but hoping to get some other opinions before I dig all the way to headgaskets. I run this thing hard, last tandem pull I did I got EOT to 250 then backed off.

Thanks for any feedback or insight.
 

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Discussion Starter · #2 ·
Filler info, pulled a dump trailer at around 8k lbs this morning, coolant around 14psi. Dumped it, bled pressure and in the 20miles home gained 2psi. Romping on it would go to 3psi and settle back to 2psi.

Deltas are great, 3-5 degrees unloaded.
Not acting anything like a "traditional" HG issue.
 

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Any loss of power?

Post #1 makes it look like the coolant is reaching max cap PSI of 16, and then offgassing and building again.

Post #2 makes it seem like no coolant issues.

Pressurization from cold to warm is normal, but what that number is I am not sure. I recall 10 PSI when my truck was warm and I bled it to nothing with a pressure check during a drive. I only saw pressure rise 3 PSI after mthat when flat and 6 PSI when pushing it hard up an extended 6% grade.

Is there any sign of leakage in a hard to find area where may not easily drip to ground? I had an external leak on the EGR and also a hairline fracture in the degas bottle. Both were hard to find with no drips and would only leak under pressure, but left a chalky discoloration the color of the coolant when inspected close enough.

How about a normal pressure check? I can pressurize my system to 16 PSI and look for leaks. I had two of the tiny coolant hoses leaking at higher pressure also.

What do you think this blue smoke is? Any smell to it?
 

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Discussion Starter · #5 ·
It does burn a little oil over the 7500mile interval. Couple quarts thereabouts. Not happy about it, but never cared enough to pursue. My opacity (FWIW) when getting emissioned is usually 0.0.

Power I think is okay, maybe a little lower at top loading than I'd like but it's only a 6.0. For reference I was loaded to 15 to 16k going up a solid grade (15-20%) and I was 40mph pedal to the floor. Don't know of that is good, bad, or somewhere in between. Pulls that weight fine @ slight grades 65-70mph.

As far as smell, I can't distinguish it as clearly any of the Big 3. Maybe sweet, maybe fuel, probably some oil. I don't know enough exactly about these heads to know what/how something is leaking down to the cylinders.

And oh yeah, blowby is negligible if not non-existent @ or around idle. Haven't tried @ high-idle.
 

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2006 F350 4x4 DRW (selfbuild camper)
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my 6.0 shows similar behavior under load (for example, steep mountain roads uphill in summer). Here I also see a coolant pressure up to 18psi under load at ECT 208°F/98°C. The pressure increases with ECT and drops again to 10-11psi at ECT 188°F/87°C.
However, I don't let my engine get warmer than 212°F/100°C EOT. I then switch the fan to full load so the temp doesn't rise any further. I've been driving like this for years, if it doesn't get worse I see no reason to worry.

The small amount of smoke is more indicative of turbo or injector, I agree with Jack. But with the small amount I would just watch it to see if it gets worse. The little bit is acceptable I think.

Recently I saw this on my son's car (a 2020 Volkswagen Golf R7 with 300HP). Here is obviously driven with even more coolant pressure than our 6.0.


Automotive tire Steering wheel Motor vehicle Gas Automotive design
 

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Discussion Starter · #8 ·
Man, 212 is low. I'm around there on a flat loaded pull. With any grade it jumps fairly quick to 220's EOT/high teens ECT. I hear the fan kick on around that 220deg mark like it should.

Next time I'm working on something, I'll finally get to the blue wire.

After it warms up today I'll get to plumb in a Schrader to pressurize and monitor. An external leak would be glorious.
 

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Discussion Starter · #10 ·
Hmmmm.. cracked injector sleeve, maybe?
 

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Discussion Starter · #12 ·
Drip where egr bypass tube meets the bottom of intake manifold. Saw a little moisture in the valley and chased it uphill to the bottom of intake manifold.

Will run some archoil for a bit and see if smoke clears up.

Looks like a big maintenance weekend is in the cards:
-leak
-STP (never confirmed as upgraded)
-Dummy/Stand
-turbo clean/refresh
-???
 

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· Compression Ignition Addict
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Check to see how clean the intake and exhaust systems are.

Also, as an FYI, the Ford Spec for blow-by is 8" H2O using a gauge and a special tool for the 6.0L at 3000 rpm for 30 seconds and oil at 175 degrees or hotter.
 
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