How to replace a 1987 ford mustang 5.0 thermostat?

Answer 1

The thermostat is located on the engine side of the top radiator hose inside the metal elbow. There are two bolts that hold the elbow onto the intake manifold. And they are a pain to get to... Thin ratcheting wrenches make this job much easier.

First step is to drain the coolant. You can remove the lower radiator hose or some radiators have a stopcock to drain the coolant. Please collect it in a pan and recycle or dispose of properly.

Remove top radiator hose at the elbow. Remove small coolant bypass hose between elbow and water pump. Unbolt elbow. Good luck. After you get it off, take note of orientation of thermostat before removing (for proper flow).

Clean both gasket surfaces very well. Any material left over or uneven surfaces will lead to leaks.

My local Carquest sells thermostat housing gaskets with a sticky side. If you can find one like this, buy it. It will make your life so much easier. Otherwise the thermostat can slip down during installation and cause a major leak.

Make sure all the holes line up on the gasket and elbow. Install thermostat into housing, put gasket on, replace elbow onto intake manifold.

The rest of installation is reverse of removal.

Most auto parts stores sell Haynes manuals. If you plan on owning a Fox-body Mustang for any length of time and plan on doing any of your own maintenance, I recommend getting one. Or something similar.