R6602 cooling system

[OSO]

Took my M139 down to get 16.00x20 tires mounted on old style combat rims today . Noticed water temp about 230f . That seems a bit warm with no load on it filled radiator up about and had water running out of filler neck and water flowing through hoses ,is there an air bleed point ,or just pull temp sensor and bleed air that way. Took 4hrs to install 7 tubes ,flaps ,mount on old combat rims ,oh tires 16.00x 20 XZL almost new . Ran out of time ,old 14.00x 20 are coming off on Friday .I will have 11 take offs from M139 bridge truck . Any one looking for large split rims? Pics will be posted before and after new tires and wheels. Wheels are old style 20 studs , but new to me!!

 

[acetomatoco]

Remember that on the 6602 you have two thermostats, I believe.. I have them new for $15 ea.. ACE (of course the old electric sender temp gauges are notoriously inaccurate...)

 

[m139h2otruck]

When we were first working on the water truck, the temp gage won't read at all, after idling for over an hour with the rad covered with cardboard. Finally took the t-stat housing apart, and no thermostats at all!! Ordered and installed the standard units (160 degree) and now the temp gage was all over the map, mostly high. Installed a new gage and sender and grounded all the gages to the truck frame/dash using additional ground loops. Now, reads 160-170 after a short time, regardless of outside temperatures. Engine is right up to temp and runs great. Still likes a lot of gas though.

I never trust the electrical gages in these trucks!! Always check with a mech. gage if at all possible.

 

[OSO]

Tried to remove the 1" plug just before the thermostat housing even tried some heat. When pulling on wrench a vision went through my mind like a big chunk of cast iron from around the plug . Stopped right there. started on 1/2" plug about 6' towards firewall had to apply heat again , that attempted worked . Poured in 2 gallons of distilled water. Just saw it starting to pool in water manifold . Dumped in another gallon 50/50 mix then another 1/2 gallon of mix .Saw level up to bottom of hole in manifold and in filler neck .Started up engine only got up to about 155F after running for about 1/2 hr never saw it that cool before . First time I filled system had engine warm poured in mix and had it bubbling out of filler neck . I thought it was full, I will always relive build up of air in system through a pipe plug from now on.

 

[acetomatoco]

easier to just take off a heater hose...of course, you need a heater to do that....

 

[OSO]

What heater? Ain't no stinking heater . Found defrost duct opening under dash. Still looking where that heater is!