Had a head gasket go on the 99 cummins and trying to get a game plan.  Haven't pulled the head yet but mechanic says these trucks are known to have issues with pitting from coolant.  If this is the case to fix the problem involves pulling the motor.  My thoughts are to just go back with a short block and have a fresh motor since all the work is done.  Who out there is a reputable engine builder before and after the sale?  Right now I'm already having issues with the builder of the new nv4500 I just put in the truck so I don't want to run into this again.  So I'm looking at a worse case scenario with the new engine.

Any coolant related pitting is caused from not flushing the system and renewing the coolant often enough. I'm at 345k miles and still have a spotless radiator and block. You have to remember every time you crank these engines over cold in the morning you sending 500-700 Amp through the block and charging the coolant a little every time. So now the pH balance now starts to drift off on the acidic side which now starts pitting any metal parts. 

 

Funny part I've been using cheap SuperTech coolant now for the life of the truck and nothing but creek water or well water. Never had a since issue. 

 

I've seen several trucks with factory coolant and they bought into to that lifetime coolant idea or extended life coolant idea and now biting them in the rear end. Coolant typically last about 50k to 75k miles and needs to be changed. You going to most likely say it looks fine. Wait till the last gallon comes out typically it darker and sometimes has sediment (dissolved cast block).

 

Well if that's what causes it that shouldn't be the problem if flushing once a year is plenty.   With that being said any thoughts on engine builders>?

While the only parent bore diesel engines that I know of requiring DCA4 additive being the Navistar T444E (aka 7.3 Powerstroke) and the Navistar VT365 (aka 6.0 Powerstroke) I run Fleetguard ES Compleat in all 3 Cummins pick ups I own.  I monitor the coolant every oil change. I have been very happy with the Navistar engine blocks when the owners took care of the molybdate and nitrite content which is what DCA4 treats. The water jackets still looked like brand new cast iron with zero electrolysis or cavitation of the cylinder walls.

 

As for an engine builder the only person I trust is myself so I would build it myself. I don't know if that is an option for you. I have used Reviva Engines a few times. Their quality is top notch. CLICK HERE

This is a Cummins ISC with about 18,000 hours of run time. Its in a service truck that runs in a coal mine pretty much 24/7. Knowing the coal mines repair practice of don't fix it if it ain't broke I am pretty sure the coolant is original to the engine. It was factory filled with Fleetguard ES Compleat OAT coolant. The block is still clean inside around the oil cooler. This engine had a failed oil cooler / filter housing gasket failure causing a bad external engine oil leak.

I use Cat ELC (extended life coolant) in everything and do fluid sampling. Cat also do concentrate elc for top ups or increasing freeze strength. About 30 years ago I had to look after 8 or 10 terex dumptrucks with Cummins NTA  855 ci diesels, liner cavitation was a big problem on them and several had to have piston/liner kits due to liner worm, they had a fleetguard water filter from the factory which contained a conditioner but it didn't stop it. ELC did. I have recently come across a used fleetguard water filter housing which i'll be fitting to the ram