07 ISX going through water? no external leaks

EGR Cooler

 

Get it fixed asap. That is a lot of coolant. Don't ignore it & be sure to have the engine oil changed. For longer egr cooler life you should pressure test the cooling system periodically & repair any leaks. You must use a 15 psi radiator cap.

 

i know of a few people with cracked heads. don't just tell them to replace egr cooler. it would suck if the egr cooler isn't bad but have a cracked head on top of it after spending 2000 on a cooler. egr are famous for leaking but also heads cracking and liners dropping.

 

Why does everyone think the problem is with the head or head gasket? These engines go through EGR coolers like there is no tomorrow! I have never replace an ISX headgasket just because it was using coolant. The only head I have replaced due to cracking was from an injector bore and fuel was getting into the oil.
Deere, are you saying he should just skip the EGR cooler and go straight for a head job? I hope you realize that changing a head when it doesn't need it is about 4 times the cost of a cooler job!!! Most coolers can be taken off in under 3 hours. There is a very simple visual inspection and also a pressure test of the cooler. If it were my truck I would have the cooler taken off and tested before even thinking about the head!

 

On the ISX, the EGR cooler is good for splitting the fins. Fiirst, any coolant in the oil? If not, that eliminates injectors, oil cooler leak, etc. Second, remove the line that goes from the EGR to the intake. Do you see moisture? Also, you can remove a hard intake line between turbo and air cooler. Moisture there? If not, most likely not at intake side of the cooler. It puts it on the exhaust side. Yes, there are 2 sides of the EGR cooler. Now, take a radiator pressure tester and apply it at radiator cap. Start truck and idle it at 1300 - 1500 rpms. Max for the ISX pressure should be at 12 psi. Cap blows at 15. Does the pressure build up past 12 or 15? If so, replace EGR cooler. Exhaust pressure will escape into coolant and in turn force the coolant into the EGR valve or through the combustion chamber. When you replace the EGR cooler, get a radiator cap. That is standard because the pressure popped the cap and the seals will not work properly.

If the coolant is not building pressure, then the fun really begins. You will need to replace the head gasket. Usually with a head gasket at the mileage you have, it would be rare. Also, these engines have wet sleeves on them and could leak, but again, that is rare on those kind of miles if the coolant filter was changed normally.

In my professional opinion without looking at the engine, I would guess that the EGR cooler needs to be replaced.