M936A2 possible coolant issues

[charlesmann]

today, I'm sure its a faulty indication caused by me digging into the dash panel today to fix an air leak for the wiper motor. i noticed the fuel and oil spill gauge wasn't acting properly either. i noticed the eng temp gauge running at 240, which until after attempting to remove the dash panel, the temp was running around 200. just on the safe side, i checked the coolant level, and it was low. i serviced the system with around 2 gallons, 1 gal of water and 1 of green coolant. then fired it up to circulate the fluid. i did not notice the level change in the surge tank once the temp climbed from around 100, back up to 240 as per the gauge. i shut it down, put my hands on the eng and rad and it didn't feel like 240, felt more like a normal running engine, same for the rad. i did pull the hose from the liquid to liquid cooler and dumped the entire system. its going to get a flush when i get back from work. i will fill it back up tomorrow with just water so it has something in it, not just a dry block for 3 weeks.

will it be good to sit with just water for those 3 wks? unfortunately, i got called and told to get on a plane wen and report back to work. so servicing with 5 gal of antifreeze and 5 of water, in a system that needs a sever flushing is kind of a huge waste of money.

since i didn't see any circulation, should i assume either my thermostat or both are not opening, the water pump just happen to take a crap or should i not see circulation in the surge tank? i will buy a temp gun tomorrow and check with the gun, what my actual eng/rad temp is running before buying a new pump, thermostats and gaskets.

any expedited help will be greatly appreciated.

 

[charlesmann]

also, should my rad/cooling fan be turning all the time while the eng is running? i thought they were temp controlled.

 

[simp5782]

A2 fans are generally normally open circuits. No air to it means the fan is on. Some use air to engage the clutch. it just depends on what type it is.

If the fan is on the the engine will not get to operating temp.

Some wreckers have an override for the shutterstat to engage when the wrecker bed is engaged with the power divider.

Will be fine to sit a few weeks in your location.

 

[charlesmann]

copy that. thank you. I'm in the process of flushing the soap out now and will at least put 5 gal of AF in it, since we are suppose to have a cold snap and suppose to get down to in the mid 20s.

 

[charlesmann]

Serviced with 8gal, 5 of AF and 3 of water. Would have put more water in, but the system just wouldn’t hold the full 40 qts the -10 says its suppose to hold. I filled the rad up first with 3 gal of AF, connected the rigid tub back to the thermo housing, opened the aftercooler drain, filled the resv tank with 2 gal of AF, started the truck up, put a rug over the from of the rad to restrict airflow and proceeded to svc with water till the aftercooler started spitting green, put the tube in the resv tank and finished filling with water. I even opened up the heater core drain and let it purge for a few sec of green coming out and closed it off.
Closed everything up, secured the hood, rmvd the chock blocks and went on a short drive (20 min round trip), shut it down and let it cool down for an hr, checked the resv tank and it was an inch below the filler neck. So I’m assuming enough coolant is in the system, including the eng.

A2 fans are generally normally open circuits. No air to it means the fan is on. Some use air to engage the clutch. it just depends on what type it is.

If the fan is on the the engine will not get to operating temp.

Some wreckers have an override for the shutterstat to engage when the wrecker bed is engaged with the power divider.

Will be fine to sit a few weeks in your location.

So when I pulled the rigid tube from the thermostat housing, I had to disconnect the airlines from a solenoid. When I disconnected just 1 of them, the fan stopped turning. So the fan is air controlled, but I’m thinking that solenoid is a temp solenoid, not working properly B.C. its corroded really bad. When I get back to the states at the end of the month, I will, after some research in the TMs, try to locate that thingy and put a new in if it is indeed a temp operated solenoid and see if the fan only comes on when the temp is at its preset point.

I’m also thinking the thermostats that installed must be 160 degree since I saw coolant flow, shot the thermo housing and it was 163 degrees.
Thoughts as an inoperable solenoid and the thermostats being a 160? Even during the drive (with the rug rmvd from in front of the rad), according to the half way working gauge, I never got above from I could tell, 190. When I twist the gauge, it goes from cold by twisting left, and to screaming hot (240 degrees) when I twist it right.