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white smoke=cracked head?

2K views 3 replies 3 participants last post by  Dicion 
#1 ·
I have an '06, 6.0 with a coolant leak! About two months ago the truck over heated because of a cracked overflow bottle. I replaced the overflow bottle and fixed that problem. A couple weeks later I had black smoke and a loss of power on take off. I replaced the EGR valve and that problem went away. A few days after replacing the EGR valve the truck is blowing out white smoke and I am having to add water and coolant. It doesn't do this all the time, when it does it's only after I first start it up and stops blowing white smoke after a few miles. Could this be a head gasket or even a cracked head and why did it show up only after I replaced the EGR valve? Thanks for any info.
 
#2 ·
Most likely your EGR cooler failed when it over heated. The EGR cooler is dripping coolant into the intake all night and burning it off in the morning. What is your eot vs ect delta? This might also be time for a new oil cooler as they fail together a lot of the time. See the t-shooting guide in my sig for more info.


Q: Engine puking coolant from de-gass tank

A: Head gaskets are bad or EGR cooler has failed.


Q: Wrench light when towing and engine looses power

A: Some newer PCM flashes monitor EOT vs ECT delta and when it exceeds 15 deg the truck will go into limp mode. Your oil cooler is obstructed and needs to be replaced. This is a good
time to do a cooling system flush and an EGR delete.


Q: Do I have a blown EGR cooler?

A: Remove the EGR valve and look down the hole, if you see any wetness, wet gooey soot, or it looks steam cleaned, your EGR cooler is bad. This is a good time to do a delete if you can, if you can't I would recommend a new cooler from bullet proof diesel.


Q: Do I have a blown head gasket?

A: Generally if there is a slow gradual pressure increases in the cooling system over 16 PSI then this points to an EGR cooler / oil cooler failure. If the pressure in the cooling system tries to head to and exceed 20psi pretty fast in a cool motor then this points to a head gasket failure. Put a Tee in one of the rubber lines going to the de-gas tank and attach the line for your gauge to that. Or buy new hose and make a test rig to use for now and then loan to all your buds later on. This is as simple as a 3/8 hose barb Tee,5 clamps, 30 PSI gauge and some 3/8 air line. Cut 2 short stubs out of the air line to span the gap between the manifold and the de-gas tank. Next since you saved the end of the air line that has a 1/4 FNPT fitting crimped to it, the free end goes to the tee and your gauge attaches to the factory crimped on FNPT fitting. You will use a gauge with a 30 full scale reading. The cap on the De-gas tank is a 16 lb relief, this is why 16 psi is the magic number. The pressure you reach is not as important as the rate of climb. The reason for the slow increase in pressure for the EGR cooler/ oil cooler failure is as follows. The oil cooler plugs up and starves the EGR cooler for coolant thus turning it into a superheated steam generator. This point source of heat and excess pressure will lead to the EGR cooler failure. In this condition some have reported the melting nipple on the de-gas tank the attaches to a rubber hose that vents steam from the EGR cooler.

The rapid rise in pressure associated with a head gasket failure is caused by combustion gasses entering the cooling system and raising the cooling system pressure until the vent on the de-gas tank cap opens and the puking starts. I think NAPA has a test strip you can use to detect combustion gasses in the coolant.

OK so with a quick check of a saturated steam chart this is what we know.

15.3 PSIg steam equals 250 degF

20 PSIg steam equals 259 degF

What this mean is that if you take a cold truck out and run the heck out of it and it builds pressure to 20PSI or more and the coolant isn’t 260 deg then it’s a safe bet that combustion gasses are entering the cooling system because you have a bad head gasket.

Water boils at 212 deg at zero PSIg. In a closed system there is a very predictable relationship between steam pressure and steam temperature. This is why cooling systems are pressurised. This way you can have 248 deg coolant that is at about 15 PSIa and you make no steam because the coolant isn’t it’s boiling temp for that pressure, it is however saturated. Now at addition of ethylene glycol raised the boiling point too but for what we are taking about we can use a table for water-based steam. If the system doesn’t get hot enough to the point it should make steam and its building pressure you know that pressure is from a different source like combustion gasses entering the cooling system. From ---- wait for it ------ BAD HEAD GASKETS.






Q: What is the delta between EOT and ECT?

A: Delta refers to the difference between the oil and coolant temperatures. This delta should not exceed 15 deg F , if it does once the truck it up to operating temperature going straight down the highway your oil cooler is plugged up.
 
#3 ·
thanks for all the info. I'm taking my truck to a diesel performance shop where they said they would a diagnostic check at no cost. Hopefully it is just the EGR cooler cause i definitely don't want to hear the price for a head gasket replacement.
 
#4 ·
If the EGR Cooler needs replacing, so does the Oil Cooler. It's the oil cooler failing that causes the EGR Cooler to fail. It's a multi-step process, and one doesn't fail without the first.

Do NOT let them just change your EGR cooler, and call it good. You'll be replacing it again in no time.

The correct procedure to fix this issue is to Flush the entire coolant system, including chemical flushes to clean it out, then replace the oil cooler AFTER flushing (Replacing before flushing will cause the flush to re-clog it). Then replace or DELETE the EGR cooler. I recommend a delete, personally, but if you MUST put a functional EGR cooler back in, I recommend the BulletProof Diesel Cooler. That way, you don't ever have to worry about it blowing again.

Once all that is done, Add gauges to monitor Engine Coolant Temperature, and Engine Oil Temperature, and you'll be able to see this coming next time before it gets bad.
 
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