Changing Thermostat

[jdowns67]

I should know this but I haven't changed one in a while. How much coolant do I need to drain just to change the thermostat? Don't want to make more of a mess for myself than I need to.

[chuzie]

It is going to be about half a gallon depending on your hose configuration.

[JayT]

Just get the level in rad lower than the t-stat housing... (a little hard to see, but that's the goal, anyway)

[jdowns67]

OK, I got it out, thanks. I heated the old one and the new one in a pot and they both open at the same time. I was hoping the old one was a 160 deg stat. It just seems like my motor won't heat up good in the winter. The heat doesn't really even blow hot air much. Maybe it's time for a new core.

[Timstrk]

If it's low on water the heater core will suffer. At higher rpm there will be enough water to circulate to the heater core but not at idle. Still enough to keep the engine cool but not enough to provide you with the heat you want. Maybe just a low water level. The tstat should have a stamp on it to indicate the opening temp.

Tim

[chuzie]

Is there a small weeper on the 12 o'clock of the thermostat? Some come with this from the factory but I just drill it out to 1/8" (I think). I will help to purge the air from your system even when the thermostat is not open.

May I assume you checked your coolant level before you removed the thermostat?

Try to flush the heater core. I recommend CLR but ONLY for the core in a closed loop. If the core is old though, CLR may just send it over the edge and eat the plugs away and cause a leak. Worst case, you spend a few $ of a new core. It is worth a try.

Flushing the engine coolant may be worth while too. You may have clogged passages or a buildup of sediment in the radiator.

Can you provide a better description of the conditions that caused you to change the thermostat?

[jdowns67]

The water level was fine. I also run a reservior. It's a new motor and the radiator has been rodded out. Coolant less than 1000 miles. I'm changing the thermostat because it just doesn't seem like I'm really getting up to operating temperature in the winter. Hard to tell about the accuracy of the factory temp gauge but it barely gets to around 160. I have an Autometer mechanical gauge run to the back of the intake and it barely gets to 130-140. Heater doesn't really blow hot air. I was hoping the guy that built my motor had put a 160 deg stat in there but it was stamped 180. I may just put a new heater core in it and check the temperature with another gauge or pyrometer. In the summer both the gauges show that it is up to operating temperature. It seems unlikely that the motor is not getting to operating temperature but I suppose it's possible.

JD