I used to have a Nissan truck and it wall turning into a regular bucket piece of s..t and someone told me it was the catalytic convertor(got rid of the truck and never fixed it to find out) now I have a ford explorer and just changed the radiator water with antifreeze, plus my power steering pump is going out so I think it is putting a drag on my fan belt a little. So we have had temps outside between 75-102 and I notice my temp gage going a little over the C line then drops a little and goes back up. I have already replaced my water pump, thermostat and radiator. I’m thinking the ammonia smell might be coming from the cooling system is this at all possible. Please only real answers of people who know what they are talking about. I really appreciate the help.