5 ton 923A2 overheating

[Willsterman]

I purchased a 923A2 during the winter and GL Fort McCoy WI has a policy of not allowing them to be started while previewing in winter. Drove it home on a 45 degree day and everything seemed OK. Took it for a drive a month ago and it smelled hot and seemed to have an engine or oil line leak but I couldn't narrow it down since oil mist covered much of the lower engine and transmission and I didn't have time to delve further into it.

So I started it today, and took it for a short drive. The oil pressure was 60 psi and the temp gauge showed 180 F while I was driving. After driving about 3 to 4 miles I stopped back home and let the truck idle. The truck smelled hot so got out and could see some "smoke" coming out at the bottom back of the engine, which turned out to be coming from the 3/4" tube or pipe that appears to be a crankcase vent tube (vertical hose/pipe near back of engine in picture). I then checked the gauges again and the oil pressure was now at 15 psi and the temp was at 220 F and the radiator fan was not running. Engine oil level is fine and I can see there is some antifreeze in the bottom of the overflow tank on top of the engine.

Seems odd the fan would not be running if the temp was that high (unless the temp gauge is wrong), but it did smell hot. I am wondering if the oil pressure dropped to 15 because the oil was so hot. There could still be a small leak near the front of the engine from the engine or an oil line fitting, but I have not located it yet as everything looks a bit oily. I wouldn't think noticeable oil vapor (smoke) should be coming out of the tube coming from the top/back of the engine that runs down below the bottom/back of the engine toward the ground . Any ideas of what to check or do next?

Thank you!

 

[R Racing]

Yes when oil gets hot it gets thin. Do not run it long like that !!! Check and see if your themostat is stuck?

 

[seano11]

First off add a few jugs of coolant to it my gf recently thought that having coolant in the bottom of the tank means it's full. This is not the case the feed tube is higher then the bottom of the tank. If that doesn't work make sure you have a thermostat in the truck

 

[162tcat]

It's probably your shutter stat. They sometimes stick from lack of use. I've had some stick on and some stick off. You can take the end off and clean/lube it but I usually just replace them. Doesn't make much sense overheating an expensive engine due to saving a few bucks on a part that is questionable.

 

[Dieselnatalie]

You say the fans not running.......presuming that its an electric fan. Short out the fan temp sender on the cooling circuit and it should run flat out. As the others contributors have said, check.....even better flush out and refill the cooling system and put the rad shutter in fully open position.

 

[doghead]

I think there is a procedure it the TM to use bolts(provided) to "manually override" the clutch fan.

The clutch fans are known to fail.

Horton is one of the manufacturers of them.(key search word)



This should be covered in the 20/24 TM.

 

[Vintage iron]

I work on a lot of A2s and they are always low on coolant. It is important that you check your coolant before every trip. Well always check all your fluids. Your coolant should be filled to the bottom of the fill tube in the expansion tank. If you see a drop then find the leaks. I have seen a lot if heater cores going lately. After you fill up your coolant, bleed the air out of the top of the engine at the after cooler. I would replace the thermostat and trouble shoot the shutterstat ASAP. I always watch the oil pressure it is a good way to judge how the engine is running.

 

[plode]

I have seen a lot if heater cores going lately.

Mine is currently bad. I have it shut off at the engine until I get/find a replacement.

 

[Willsterman]

Thank you for all the quick replies. I have replaced thermostats on car engines and a john deere dozer so I can probably handle that. Vintage Iron mentioned ".....replace the thermostat and trouble shoot the shutterstat ASAP" I am unfamiliar with a shutterstat, where do I find that part on the engine and how is it different than a thermostat?

The truck does have the clutch on the radiator fan that is only supposed to kick in when the fan is needed. Seems the clutch should have engaged so I will also look at trouble shooting that, but will start with adding some antifreeze since that is the easiest first step. I am guessing that bleeding the air out of the top of the engine at the aftercooler is covered in a TM, so I will try and find that location in the TM.

Can I get a thermostat and shutterstat at NAPA for the 8.3 Cummins turbo diesel?

Thanks again for all the quick replies!

 

[M35A2-AZ]

Sounds like your fan switch in not working or the clutch is bad. Put some air to your Fan clutch and see if it comes on.

 

[162tcat]

If you look at the base of the fan, you'll see an air line attached to it. Follow that line back to a brass valve with 2 air lines attached, that is the shutter stat that turns the fan on. Now if you bypass that and hook the 2 lines together (with an 1/8" npt coupling available at lowes, depot or similar store) the fan should be on continously, you'll hear a loud roar of wind and fan. If that's the case, your shutter stat is bad. If the fan doesn't work, the fan clutch is bad.

 

[doghead]

There should be step by step troubleshooting instructions in the TM.

 

[Csm Davis]

Okay all of these are good to check after you fill your coolant system back to full. Then if you still have problems check the fan and other things. It sounds like you have little to no coolant, which will cause the fan not to come on because the switch is not being covered in fluid.

 

[goldneagle]

The thermal switch that turns on the fan clutch is repairable. I and other members have taken it apart and reconditioned it. Usually it needs some lube and possibley a couple of o-rings. Its fairly easy to rebuild. Mine works fine since I lubed it.

 

[162tcat]

Any update?

 

[70deuce]

My solution. Post #84

http://www.steelsoldiers.com/showthread.php?83932-Actuator-Air-Fan-Clutch-for-M923a1/page9

 

[Willsterman]

Thank you for all the replies! I will be working on the truck this weekend and will post the results.

 

[Willsterman]

I put about 2.5gallons of antifreeze and 2.5 gallons of water into the truck. Maybe I am dumber than I look........... I took one short ride and the temp stayed down, the oil pressure stayed up, and so far I have not found any leaks. I didn't notice any excessive smoke, but I will do some more checking in the near future to make sure the level is staying up and everything is working OK.

I had my tractor, a ATV, and the 5 ton truck all parked next to each other outside in the woods for a while while doing some work on the land, and they were then not used for a few weeks. Interestingly the next time I went to use the ATV it wouldn't start and I found the wires were "cut" by some mice, then when I went to use the tractor it wouldn't start and I still haven't figured out why that is, but a safety switch (not the seat) appears to be preventing the solenoid from sending juice to the starter so I have to run a jumper from the battery to the solenoid to get the tractor started, and then the 5 ton started overheating and the coolant was empty. Coincidence???

Thanks for all your help and replies. This is a great website and wonderful resource!

 

[Hawssie]

And there is no manual lock in for fan clutches on M939A2s like the earlier versions with 250 NHC. My experience the fan rarely comes on much in normal driving conditions. The cooling system is giant for the displacement of the 8.3L

 

[Coffey1]

My 250 runs 160 to 170 all the time and fan rarely kicks in.