Rep Power: 0

I have no hoses connected to the heater core and I tested for a blown head gasket already and it not that , recently changed the water pump, checked the thermostat , and changed to a new fan switch. I have a po135 code . I’m not sure what the problem is at this point and I also changed the cap on the radiator.

 
Rep Power: 225

That code is for the primary O2 sensor, possibly faulty.

How did you test the head gasket? These will often pass standard HG tests but have still failed. Is the coolant reservoir overfilled/overflowing while the radiator is low? Below is a thread with info on HG testing.

https://www.civicforums.com/forums/3...reference.html

 
Rep Power: 0

i tested with the liquid and turkey base thing in the radiator. And yes the reservoir over flows if you fill the radiator to the top and let it heat. If I don’t add enough it just evaporates with the heat

 
Rep Power: 225

Turkey base thing? Sure sounds like a bad head gasket. The two tests in that thread will prove it.

 
Rep Power: 0

hahaha ok I’m going to look at the head gasket anyway. Might as well

 
Rep Power: 0

I just ran the car again and the water in the reservoir is boiling and coming out the top

 
Rep Power: 368

headgasket, if you read the link provided

 
Rep Power: 225

Have you tried to properly bleeding the coolant system? If there's air trapped inside it can cause similar symptoms.

Basically lift the front of the car up high, remove radiator cap (if cool), fill radiator, start engine (with cap still off), let engine warm up while you continue to top off the radiator. Usually you turn the heat on full blast but it looks like you have no heater core connected. This will likely make a mess so be prepared.

 
Rep Power: 0

I tried that but the steam keeps coming up from the radiator and I don’t want to warp the engine
and the boiling wasn’t stopping