Hi All

Going to be replacing my thermostat and was thinking if it was possible to change it with NOT draining the coolant. Seeing the thermostat is sitting on the top of the motor I wouldn't lose much coolant. Is this possible or will it drain out?

Thanks 😊

 

You will lose about 1/4 to 1/3 of the coolant, but no you don't have to drain the whole system

But if you are chasing an overheating issue then you may want to flush the system and heater core and refill with just plain water and run it a few days that way

Coolant lasts 2 years, and needs to be changed, or you will be chasing overheating issues, lol

 

Thanks, I did have an issue with overheating and found my rad cap was no good. I also replaced the rad and thermostat. When I replaced the thermostat I went with the 180 degree one instead of the 195 that was recommended. Now I'm not getting any cab heat seeing the weather is getting cooler where I live.

Thanks 😊

 

The 195deg is better, it gives best MPG and cleaner oil, but 180deg is OK to use, neither would effect heat in the cab, 180deg is VERY HOT to us humans, lol

You need to flush the heater core or replace it, easy to do up thru 1994
Cold engine
Pull off heater hose at the firewall, there is no IN/OUT direction so hoses can go on either way
Use garden hose to flush out heater core in BOTH directions, you should be able to tell if it has good flow or not when doing this
If flow is poor then order a new heater core, under $40, just 4 screws in the cab to remove old and put in new
If flow is good now then put hoses back on

In a 1993 the heater core is the thermostat by-pass system so must always have good flow, if core doesn't have good flow then you will see random spikes on temp gauge while driving, never overheating levels, i.e. 3/4 on gauge, but will go up above 1/2 and then back down to just below 1/2(where it should be), and randomly

You should reverse heater hoses on the core every 2 years when you change coolant, this will reverse the flow thru the core(back flush it) and help to keep it cleaner
You should remove either heater hose at the firewall when refilling the cooling system, this will let the air out of the engine side of the cooling system

1993 uses a cable and slider lever to control cab temp, it opens and closes the Blend Door that routes air from the blower/fan either thru the heater core(HOT) or around the heater core(COLD), or anywhere in between, that's how temp in the cab is controlled
These are usually reliable and you can hear the blend door moving as you operate the slider control

 

Thank you sir, i changed out to the 195 degree thermostat and have heat now, however when I use the defrost it blows cold air? When set to anything else I have warm air. I will definitely do another flush as you recommend next weekend. As always thank you 😊