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Yes, when thermostat opens the hose should be hard to squeeze in.
Here are directions:
The check engine light being on can be significant. You could have a faulty ECT(engine coolant temperature)sensor.
You need to have the computer read for any stored tourble codes. You can have this done at Autozone for FREE. The check engine light being on may be totally unrelated, but you need to find out what the trouble codes are in order to know.
The problem might still be the thermostat, but until you get the codes read, it is just a guess.
Here is a diagram and photo of ECT sensor. Simply unplug connector and loosen and remove sensor: