M923a1 failure, need input.

[elkhtr]

Went to take the girls for the once a month spin down to the ice cream store.
Pre flight checks were good.
About three miles down the road I notice the temp gage at a little over 200 deg.
This truck has never ran that hot before.
Another half mile or so and it's at 210.
I plan for a landing strip at the local church parking lot, and we make it there safely.
I shut the truck down and open the hood to see what is going on.
Nothing abnormal except slight smell of coolant.
I restart the engine to see if the fan is working and I get a steam sauna shooting from the crank case vent tube coming out of the valve cover.
Shut her down, pull the filler cap, and see milky white goo.
Pull the dip stick, water in oil.
After the wrecker got me home I had to start it briefly to get her parked, started normally and ran fine.
At this point I am feeling a little gut punched.
Oil cooler? worse?
Anybody else had this happen.
And I will apologize in advance, I havent searched yet, just looking to share my misery.

 

[Suprman]

Sounds like a head gasket or cracked piston sleeve. There are a few threads with similar stories.

 

[droprat]

Elkhtr,
I felt that gut punch too in the Spring of 2012. My 931 got coolant in the oil. After tearing into it, we found that the sleeve seals were installed incorrectly during military rebuild. 3 of the sleeves were done as well as cylinders. Rebuild is very possible if u have knowledge, time, place and tools.

 

[162tcat]

Droprat and Elkhtr,

What year did your trucks go through depot rebuild and where?

 

[droprat]

My 931 was rebuilt in 2006 at Red River. My 810 was rebuilt in the 90's at Toole.

 

[162tcat]

Red River rebuilds are trouble in my experience. I've parted and fixed many RR trucks and the only thing going for them was a coat of CARC and even that was rough on some of them. I think RRAD is actually a middle school auto shop class.

Doing an "in frame" on the 250 is fairly easy. Bearings should be fine with limited run time so new sleeves and gaskets should get it done.

 

[droprat]

162tcat
I have heard the same about Red River!

 

[elkhtr]

As far as I know, mine was never rebuilt.
Showed 29,000 miles on odometer when I got it.
I know this doesnt mean squat, but it has always ran great before today.

 

[droprat]

Elkhtr
Did u check ur DCA Ph balance in ur coolant? Test strips are available at truck stops and most heavy equipment stores. If If Ph is not correct Electrolysis can occur. Ur liners pretty much develop holes and seep!

 

[droprat]

A lot of things could have gone wrong! U just won't know until u tear into it!

 

[1 Patriot-of-many]

Most likely not the oil cooler. Oil pressure is higher than antifreeze pressure. Oil in the coolant is probably oil cooler. One of my trucks a 923 had oily coolant when I picked it up from Camp Ripley. When it got hot it would force coolant/oil out the overflow from the coolant reservoir. Doesn't sound good. Hijacking your thread, what do I need to test my antifreeze for? I bought regular coolant from walmart. Do I need some type of additive for the NHC250?

 

[elkhtr]

Any suggestions on where to begin looking.

 

[TXFirefighter]

Start by draining the oil pan and dropping the pan. Put a radiator pressure tester on the cooling system and pressure it up. When I was with Ford Heavy truck, we would put about 10 to 12 lbs pressure on the cooling system. Then watch for the drip underneath. That way you can track it to which cylinder and if it is a liner seal, pin hole in the liner or above the piston.
We had a lot of old NTC's that had corroded areas around the liner seals because the coolant system was not maintained properly. Controlling the pH and maintaining the correct SCA level is a big deal in avoiding system failures.
The others are correct, these engines are not hard to work on with the right tooling and it is probably not the oil cooler as stated above.

I have repaired the lower liner seal area with extreme cleaning and applying JB weld. Not the preferred way but the engine lived for 4 more years before the owner sold it. I have no idea how much longer it ran after that. It sure took a heck of a lot of sanding to smooth the epoxy and blend it into the bore.
Liners are know to develop pitting due to cavitation. It shows up in between the cylinders and can get bad enough to penetrate the liner and dump coolant into the crankcase.

 

[elkhtr]

Start by draining the oil pan and dropping the pan. Put a radiator pressure tester on the cooling system and pressure it up. When I was with Ford Heavy truck, we would put about 10 to 12 lbs pressure on the cooling system. Then watch for the drip underneath. That way you can track it to which cylinder and if it is a liner seal, pin hole in the liner or above the piston.
We had a lot of old NTC's that had corroded areas around the liner seals because the coolant system was not maintained properly. Controlling the pH and maintaining the correct SCA level is a big deal in avoiding system failures.
The others are correct, these engines are not hard to work on with the right tooling and it is probably not the oil cooler as stated above.

I have repaired the lower liner seal area with extreme cleaning and applying JB weld. Not the preferred way but the engine lived for 4 more years before the owner sold it. I have no idea how much longer it ran after that. It sure took a heck of a lot of sanding to smooth the epoxy and blend it into the bore.
Liners are know to develop pitting due to cavitation. It shows up in between the cylinders and can get bad enough to penetrate the liner and dump coolant into the crankcase.

Thanks Texas!
That is a great suggestion on where to start.
My thinker is not working well at the moment.

 

[droprat]

I use Fleetguard test strips to check pH level in coolant. Then add DCA-4 to balance pH.

Personally I don't use the 50/50 pre-mix coolant. Travelers plain coolant from Tractor Supply for example is good; and distilled water.

 

[machinist75]

Mine did the same thing. The air fan actuator went out causing the fan not to kick on, overheating it. Drained oil, about 3 gallons of antifreeze in the oil. Sick feeling. Dropped the pan, bunch of metal chunks, even sicker feeling. The number 5 cylinder liner had popped around the bottom orings where the coolant flows around them to keep them cool and let all that coolant flow into the motor. It was just the bottom so it wasn't affecting the piston at all. It wasn't smoking or making any noises. I was able too see the liner popped from underneath with a flashlight. It sucks. Waiting till after Christmas to get another motor. We all need to rebuild the airfan actuator with new orings.

 

[Postman515]

Just had my 8.3L overhauled because of the liner o-rings were installed wrong. Luckily I caught it soon enough, just had a little steam out of the blow-by and no antifreeze in the oil.

 

[rhurey]

Waiting till after Christmas to get another motor.

So, maybe dumb question, but is this really a new motor problem? Damage further than the single cylinder liner?

 

[elkhtr]

Mine did the same thing. The air fan actuator went out causing the fan not to kick on, overheating it. Drained oil, about 3 gallons of antifreeze in the oil. Sick feeling. Dropped the pan, bunch of metal chunks, even sicker feeling. The number 5 cylinder liner had popped around the bottom orings where the coolant flows around them to keep them cool and let all that coolant flow into the motor. It was just the bottom so it wasn't affecting the piston at all. It wasn't smoking or making any noises. I was able too see the liner popped from underneath with a flashlight. It sucks. Waiting till after Christmas to get another motor. We all need to rebuild the airfan actuator with new orings.

The fan definitly wasn't the cause of my issue, it was working properly.

 

[Scar59]

Had the same problem w/ a M931A1, water in the crank case. Had the pan pulled and found # 3 cyl. sleeve scored/cracked. Traded the truck out to some one with more time and resourses.
Good luck
JC