Ford 4.0L Index of Articles

Testing the upstream oxygen sensors (O2S11 and O2S21), on your OBD II equipped 4.0L Ford Aerostar, Explorer, Ranger, or Mountaineer, can be accomplished in a few easy steps... [read more]

Checking whether your 4.0L Ford Explorer (Aerostar, Mountaineer) has a blown head gasket can be done with one of four different tests and in this article I'll show you how... [read more]

You can easily test the alternator with a multimeter to find out if it's bad or not. Not to mention that you don't need any expensive testing equipment to do it! In this... [read more]

If you've been wondering if it's possible to test the thermostat (without replacing it on a hunch), the answer is YES! The thermostat can be tested while it's still on the... [read more]

One of the most common problems, with MAF Sensor equipped Ford (Mercury and Lincoln) vehicles, is that the MAF Sensor’s Hot Wires will get dirty (contaminated). This... [read more]

A compression test will let you know if the hard-to-diagnose misfire (or rough idle) condition or no-start condition is due to something wrong inside the engine (like worn... [read more]

In this article I'll shed some light on how to test and diagnose a Ford (and Mercury) V-6 Ignition Coil Pack. You’ll learn how to... [read more] at:

Testing the fuel injectors on the 1991-1996 4.0L Ford Explorer and Aerostar can be quite a challenge. Why? Because three of them are under the intake manifold plenum. Also,... [read more]

Testing the Ford Mass Air Flow (MAF) Sensor on all of the Ford, Lincoln and Mercury cars and trucks is a very simple test that can... [read more] at:

This tutorial will show you how to test the starter motor on your 4.0L Ford Explorer (Aerostar or Mercury Mountaineer) to see if it's the one responsible for your engine's... [read more]