Engine overheating issue

joshybob

Hi guys. I'll go ahead and explain my situation. My 04 ford mustang ft is overheating. There are no leaks other than when it overheats the cap starts to smoke and spew antifreeze. See the thing that gets me is that it's not leaking antifreeze until after it starts overheating or get to almost the red line. I don't let it get to the line though. I thought replacing the cap wouldn't really do anything because it's already over heating by the time it gets to the point where it's leaking antifreeze from the cap. Another side note I can smell it in the car not sure it that means anything I think it was coming from the vents. It all started happening after I had a friend try and recharge my ac. He did it on his car and it worked fine so I thought he could try it on mine. After he finished putting the r134 in we had the AC on blast and then all of a sudden the AC got super warm and then the smoke started coming from the expansion cap and the car started to over heat. Thanks for checking it out guys.

Mr_Shiftright

I'm trying to correlate the AC charging with the overheat--if it's not just a coincidence, and the only thing I can come up with might be that the AC system is radically overcharged (if your friend used one of those refill cans with one gauge, then overcharging is easy to do), and the AC compressor is dragging badly on the engine. Usually you'll hear belt squeal but not always, and a dragging compressor can put a lot of strain on an engine.

Why don't you try unplugging the AC compressor clutch and see what happens?

Otherwise, if that's not it, then you'll have to start a diagnostic, beginning with the basics of checking your electric cooling fans and checking for a stuck thermostat (and yes, a defective radiator cap).