Thermostat Question

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Eric, Apr 20, 2000.

  1. Eric

    Eric Registered Member

    Mar 21, 2000
    Likes Received:
    Got a question for all you out there:
    Just replaced the raidiator in my 86Blazer. Filled it up with fluid and started the truck. Noticed that there was a lot of flow in the radiator while the truck was still cold. I thought that this was only supposed to happen when the thermostat opened?

    Next I replace the thermostat (195). Looked inside the radiator and lots of flow again. The truck was cool in this case too. What is going on? Is this normal?

    Thanks for the help.

    86 K5 Blazer
  2. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

    Feb 17, 2000
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    Well depends on the heater set up. Some trucks the heater return dumps into the radiator some it dumps into a fitting on the water pump. The heater core is alwasy reciving water so even if the heat is off in the truck if you have the one that goes to the radiator for it's return then you will get some flow.
    My personal oppinon is this is better and the reason being is it preheats the radiator so that when the Thermostat does open you not hitting the block with stone cold water when the block is at 180 deg. With your 86 I would run a 180 thermostat unless you got real cold winters. While you have some controls that work on the water temps since you got the CCC carb you not full blown FI and it should run fine with the cooler stat.

    Diging it in the dirt with my K5's

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