Civic 1991 LX 1.5L 203,000 miles

First, I am trying to change the o2 sensor, but I am having trouble with torqueing the one there now. Because it is on the exhaust manifold, should have to warm the engine or will an impact gun work with no damage to the vehicle?

Second, after I purchased the car, one of the first repairs I had done was the radiator. After quoted a price of four hundred dollars which included thermostat change and something else, I went to another place and they most likely only just changed the radiator out at two hundred dollars.

Now, after the radiator change, when I began using the AC, after a few minutes a smell would come from the vents and the air was not cooled. So, I purchased a refill kit and cehcked the pressure that was between the 20 - 25 - normal.

When I use the AC, the radiator fluid resivior begins to drop dramatically considering when I don't use the AC it will stay constant for months if not years.

Also, if I turn it on in a parked position, it will blow fine until I being to move then the engine will begin to labor as the tachtometer reves.

Any assistance would be appreciated,
MC

 

For the o2 sensor I don't think you can get an impact on there, because the sensor is in the way. They make a special socket for o2 sensors, but I recall using an open-ended 7/8" wrench.

No clue about AC sorry.....