The 6.0 does have a head gasket sealing issue, but that doesn't automatically mean every symptom that looks like a head gasket failure, is actually a head gasket failure. Plus, by now, 20+ years after the engine was released, most have head studs anyways. Either way, here's a quick and dirty checklist to help you figure out what's actually going on with your 6.0L Powerstroke cooling system, before pulling the heads. 

Don't Immediately Assume Head Gaskets

Coolant around the degas bottle can come from:

• Overfilled coolant venting
• Weak cap
• Damaged bottle neck
• External leak
• Failed EGR cooler
• Restricted oil cooler
• Overheating
• Head-gasket leakage

Work through them in that order.

 

Check Coolant Level and External Leaks

Check the truck completely cold. Then inspect the:

• Degas bottle and cap
• Radiator
• Water pump
• Thermostat housing
• Heater and radiator hoses
• EGR cooler connections
• Coolant crossover connections

Fix any obvious leaks before moving on.

 

Test the Degas Cap

With the cap installed, connect a pressure tester inline with the degas bottle hose and slowly pressurize the system.

The cap should release between roughly 12 and 18 PSI.

If it opens below 12 PSI, replace it.

Also inspect the bottle neck for cracks or damage.

Most importantly, record the actual pressure where the cap holds or vents. You'll use that number later.

 

Rule Out the EGR Cooler

A leaking EGR cooler can mimic head-gasket failure. Cracks in the EGR cooler will put exhaust into the cooling system just like a head gasket can. EGR failures are just as common as head gaskets, alwyas ferify EGR issues first

Common clues include:

• Coolant loss
• White exhaust
• Degas bottle venting
• Excessive cooling-system pressure
• A wet EGR valve

Check the Oil Cooler

Monitor:

• ECT
• EOT

If EOT runs 15°F or more above ECT under those conditions, the oil cooler is considered restricted. That 15-degree number is an oil-cooler test, not a head-gasket test. Also common, cracked oil coolers. A failed/leaking oil cooler will generally introduce oil into the cooling system. Many can assume the oil is from a failed head gasket. More often than not, oil in the coolant is an oil cooler issue. 

 

How to Test for Combustion Pressure

Once the prior mentioned are ruled out:

1. Leave the cooling-system pressure gauge installed.
2. Carefully release the existing system pressure.
3. Road-test the truck under heavy load.
4. Build maximum boost.
5. Watch cooling-system pressure.

Now compare it to the cap's verified holding pressure.

If Pressure Stays Below the Cap Holding Pressure: The loaded pressure test does not point toward head-gasket leakage.

If Pressure Exceeds the Cap Holding Pressure: Now the diagnosis moves toward overboost or combustion pressure entering the cooling system.

Also check the VGT and EBP systems here because excessive boost can increase cylinder pressure and contribute to head-gasket failure.

 

Forget the Hard-Hose Test

A hot upper radiator hose is supposed to be firm. That alone tells you nothing about where the pressure came from. Use a gauge.

 

Quick Diagnostic Order

1. Check coolant level cold.
2. Repair external leaks.
3. Test the cap and bottle.
4. Rule out the EGR cooler.
5. Check ECT versus EOT.
6. Release existing pressure.
7. Road-test under heavy load.
8. Compare cooling-system pressure to the cap's measured holding pressure.

 

The Bottom Line

Coolant puking from a 6.0L degas bottle does not automatically mean head gaskets.

Test the cap, find leaks, rule out the EGR cooler, check the oil cooler, then load the engine with a pressure gauge installed.

If cooling-system pressure exceeds the cap's verified holding pressure under boost, now you have a real reason to start looking at head gaskets

Related Products:

Motorcraft Degas Coolant Bottle Cap

https://www.riffraffdiesel.com/degas-coolant-bottle-cap/

Riffraff Diesel Billet Degas Bottle Cap 96-10

https://www.riffraffdiesel.com/riffraff-diesel-billet-degas-bottle-cap-96-10/

Oil Cooler Kit 03-07 6.0L

https://www.riffraffdiesel.com/oil-cooler-kit-03-07-6-0l/

Bullet Proof Diesel Round 6.0L EGR Cooler

https://www.riffraffdiesel.com/bullet-proof-diesel-round-6-0l-egr-cooler/

Bullet Proof Diesel Square 6.0L EGR Cooler 03-07

https://www.riffraffdiesel.com/bullet-proof-diesel-square-6-0l-egr-cooler-03-07/

EGR Cooler Gasket Install Kit 03-07 Complete

https://www.riffraffdiesel.com/egr-cooler-gasket-install-kit-03-07-complete/

Thermostat Assembly 03-07

https://www.riffraffdiesel.com/thermostat-assembly-03-07/

Riffraff Diesel 6.0L Billet Thermostat Housing

https://www.riffraffdiesel.com/riffraff-diesel-6-0l-billet-thermostat-housing/

Bullet Proof Diesel Billet Water Pump 03-07

https://www.riffraffdiesel.com/bullet-proof-diesel-billet-water-pump-03-07/

Riffraff Diesel Coolant Filtration System Filter Kit 03-07

https://www.riffraffdiesel.com/riffraff-diesel-coolant-filtration-system-filter-kit-03-07/

Fan Clutch HD Snow Plow Package 03-07

https://www.riffraffdiesel.com/fan-clutch-hd-snow-plow-package-03-07/

 

 

Disclaimer: The information provided on this blog is for informational purposes only. We share our knowledge and experience, but we are not liable for any damages, injuries, or losses that may occur as a result of using this information. Situations are rarely cut and dry in the automotive world. Your situation will likely be somewhat different than what we describe here. Use your best judgment and always consult a qualified professional for automotive repairs and modifications. Your safety is your responsibility.