Compression Ignition Addict
Join Date: Mar 2011
Location: wichita ks
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Sorry to break it to you man, Looks like Head Gasket, here why. You still need to check for a blown EGR cooler they kind of go together .
Q: What’s the white crusty stuff around my coolant tank / de-gas bottle
A: Your engine is suffering from a condition called coolant puking. Two scenarios cause this.
#1 Your oil cooler is plugged up and starving the EGR cooler for coolant turning it into a steam generator this flash boiled coolant is entering the de-gas bottle from the rubber hose that leads from the manifold and puking out as it over pressurized the de-gas bottle.
#2 You have a blown head gasket. Combustion gasses are entering the cooling system and over pressurizing it causing puking out the de-gas bottle cap which should vent at about 16 psi.
Q: Do I have a blown EGR cooler?
A: Remove the EGR valve and look down the hole, some times the truck will have to be parked nose down over night. 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.
Last edited by HAM_RADIO_MAN; 12-12-2011 at 06:43 PM.