5811585 Temperature Testing Tool
The 5811585 tester can be used for checking a blocked heater core (or bad thermostat).
Connect one wand to the inlet of the heater core (metal is exposed or heater hose) and the second to the outlet.
If the thermostat is good, you should have 190-210 degrees. Fahrenheit at the inlet. If the heater core is not blocked, the outlet should be 10-25 degrees colder (difference is the heat transferred inside of vehicle).
If the outlet is 50-80 degrees Fahrenheit colder, the heater core is restricted to some extent. If the heater core is found to be open, but customer is not getting any heat inside, it may be an inoperative temp actuator or broken temp door.
Connect one wand to the inlet of the heater core (metal is exposed or heater hose) and the second to the outlet.
If the thermostat is good, you should have 190-210 degrees. Fahrenheit at the inlet. If the heater core is not blocked, the outlet should be 10-25 degrees colder (difference is the heat transferred inside of vehicle).
If the outlet is 50-80 degrees Fahrenheit colder, the heater core is restricted to some extent. If the heater core is found to be open, but customer is not getting any heat inside, it may be an inoperative temp actuator or broken temp door.
Click "Download File" for the PDF version.

20_5811585_used_with_heater_cores.pdf |