my 83 tr4 thermostat replace

[Mark]

To test the thermostat, park the car when it's cold and start it up. The top radiator hose should start to get warm, but the bottom hose should be relatively cool (meaning there is no flow through the radiator since the thermostat should be closed). When the temp gauge reaches near the middle, the thermostat should open and the radiator and the bottom hose should get hot.
I've had a few bad thermostats that got stuck open, including the newish one I have now in my '81 Tercel. The giveaway is when the temp gauge drops well below the middle when driving on the highway. In sub-zero weather a stuck open thermostat would probably prevent the gauge from reaching the middle at any driving speed.
Is there coolant (about half-full) in your plastic reservoir?

[Petros]

actually it is the upper hose that gets hot, that is the heated coolant flowing out of the engine; the lower hose should be warm (or a lower temp from the upper) because it is drawing the cooled coolant from the bottom of the radiator. that is how the radiator works, hot water in, cooler water out. so when fully warmed up, the upper hose should be hotter than the lower hose.

[simon84]

Thanks David. I will have to try that before I go trying to invent new ways to control the heating.
As for the T-stat, when I was looking it over and topping up the coolant, the top hose did get warm while the bottom hose stayed cool. That tells me the T-stat was not stuck open.
There was no coolant in the overflow so I probably should add some.
Thanks for all the tips. Stoked to finally get some heat going in a tercel.

[dlb]

if you do a custom cardboard grill, you better post pics. supa g-unit.

[simon84]

If I do a winter grill upgrade then it won't be cardboard. That's so Cobble Hill!

Here's the last grill upgrade from the pumpkin.

[jimcrazy]

just a update, put new foam on both top and bottom doors in heater box yesterday, when I started this the heat coming out of the vent above the heater controls was at about 95 degrees, putting new foam and adjusting the doors and new foam around the heat pipes and white box brought it up to about 125 degrees. but running the fan on high it dropped to 100 the fan was cooling the core faster then it could heat up. fan on low it was fine. back at it this am backwashed the heater core lots of gunk, flushed both ways 4 times hooked back up heat at 145 out the vents cant believe it, it will dry water on foor mats. next see if I can get to the flap door that puts the air to defrost to see if I can get it to work better.

[dlb]

jimcrazy, how did you flush out the heater core?

[jimcrazy]

used a garden hose hooked to my shop hot water heater, just put a piece of 3/4 copper pipe in the hose to the heater return and connected a another piece of hose to it to put in a bucket, had a garden hose adapter to put in the heater core inlet hose and screwed it on to the garden hose, they were clamped on with the hose clamps, then just opened the valve on the hot water wide open for about 30 seconds. all the crap went in to the 5 gallon bucket, then just swaped the hoses on the heater core and repeat 2-3 times back and fourth or till no more crap comes out, got close to 1/4 cup of old grey chunks of stuff. just got home from a 1 hour drive its 35 degrees out side not real cold out but had to turn the heat down it was to hot,thats with the fan shut off. nice to have heat for a change. of the 7 wagons I have had this is by far the best heat I have ever had . even the control lever for hot to cold works right, before if you moved it from hot 1/4 the way toward cold it was instant cold. the new foam did the trick