[treywink]

Before you change the thermostat check the one you have. The heater output symptoms you describe may indicate that your existing thermostat is faulty. Get a repair manual to expound on the troubleshooting considerations that you are delving into. The book will also give you some detail on disassembly of your car to remove your heater core as you initially queried at the start of this thread. Personally, I recommend the Haynes repair manual which is very descriptive and inexpensive. I use several different manuals, there’s no point jumping into this without some reputable references.

Additionally, a hotter thermostat will mean that your engine will always run hotter, and remember, it’s heat among other things that kills engines. Don’t change to a hotter thermostat unless you’re willing to accept the other trade-offs. Your car was designed to run as built for good reasons; generally for better efficiencies and economy of operation. Good luck!!