I'm going to work on the Jeep today when I get off work. What should I look for? What sensors should I check? I really want to take my valve cover off and check the head and the oil up top. I just replaced my valve cover gasket about a thousand miles ago. Do I need a new gasket or will I be ok with reusing it?

 

Mixing coolant types shouldn't hurt anything. You can mix green and orange and be just fine.

In the oil, you're looking for anything in it that doesn't look like oil. If there's coolant in it, it will look kinda like a milkshake. Google search coolant in oil to get an idea.

If you get your valve cover off without tearing it, you can re use it. Have a spare handy, though.

 

As for sensors there's a few. On the throttle body, you have the idle air control (IAC) and throttle position sensor. On the intake manifold, there's the intake air temperature (IAT) sensor and vacuum fittings that need to stay clean. The coolant temperature sensor is on the thermostat housing. This is the one that runs the computer, not your gauge. Your O2 sensor is just below the flange where the manifold connects to the pipe, plus downstream O2s if you are so-equipped.

 

With that newer Cherokee, you probably have a mass airflow sensor, also, or something to that regard. I'll post more later when I get the chance. Disconnect and clean all your grounds if they look dirty or corroded!

Sorry for typos, on phone today