After a couple of years of not worrying about the lack of heat in my "89 7.3 my old age is dictating ''I need to fix it''....I put cardboard in front of the radiator again with the hope of raising the temp enough to make it bearable but after a trip to Columbus,Ohio last night it's not enough..I'm thinking that maybe my thermostat is stuck ''open'' as my brother in law thinks!..Anyone with any advice as to the proper temp thermostat, the location on the engine, and any helpful hints for removal and replacement would be doing an old fart a good deed....Many thanks and happy holidays to all!!...Seems like they used to be easy to replace but the last one I did probably was on an old small block chevy or slant six dodge....been awhile......
Thanks again

 

The upper radiator hose attaches to the thermostat housing neck.



195 degree thermostat, which needs to come from Ford or International to get the correct one.
I have seen many posts about thermostat problems, and most of them were from people that installed thermostats from regular parts houses instead of Ford or International.

A couple guys have used thermostats from the parts houses without problems, but they are in a minority.

 

Just another little bit of info, you might want to go ahead and flush out at least the heater core while you are at it. I know back when I got my old truck it would get to operating temp and the heater was still crappy. I took the heater hoses off the engine and then used a water hose to blow it out, at first nothing ran out, so I alternated which hose I had the water hose hooked to and finally a trickle of sludge came out and then it puked out all kinds of nasty crap. After I done this the heater was nice and hot. Yours might not be this but more than likely it couldn't hurt to flush it.

Oh I thought mine was caused by stop leak because the truck had a new radiator on it when I bought it, but my buddies 94 done the same thing and he bought his brand new and said it never had any stop leak in it.

 

i just installed a new heater core in my 89 $39.00 from napa
takes about an hour or less to install

 

My 93 has the blend door which is cable operated........ if yours is cable operated there may be an adjustment in the glove box. As well the blend door hinges may break and garbage fallen down the defrosters may be stopping the door from closing/opening correctly.

CAUTION:
The specified/required thermostat does not contain an internal bypass, since the bypass is located in the cylinder block. Whenever the thermostat is replaced, it is mandatory that only Motorcraft E5TZ-8575-C or Navistar 1807974C94 thermostat be installed.

CAUTION:
Do not attempt to repair any thermostat. It should be replaced if it is not operating properly.

Check the new thermostat before installing it for correct opening temperature. Before suspending in boiling water, with a flashlight check where the rubber and the flat metal flange meet for bad seal. Tstat should start to opening barely at 180-192f, fully open 200-212f, allow to cool and check for rubber seal again.

Removal: Disconnect batteries, drain 4+ gals A/F, remove: as required, fan belt, alternator set aside, alt bracket, remove filter support from fuel filter then e/block. Disconnect upper rad hose at rad, remove tstat bolts and gooseneck housing. Clean both faces, depression and holes in block, ensure check ball in gooseneck is clean, free and rattles "do not remove".
Installation is reverse proceedure, I do not use sealant on gaskets and faces. REMEMBER the tstat pellet(copper end) goes into the block. I do use a "very small amount" of sealant on the edge of the tstat face when installing into the recess, now go for coffee, allow sealant to setup, this has saved me from tstat slippage when the gasket and goosekneck are installed. Replace all items in reverse order......

Manifold bolt torque......... 20ftlbs

 

thanks everyone...I thought that might be where it was but thought I should check with some experts...Is this a great site or what??...thanks again....

Oldgold....1989 F250..182000..5sp...4.10...still stock...last truck was a 1980 slant six...I stilll feel powerful...