Tech Tip: Oil Leak Repair for 1990-’93 4.0L Ford V6 Engines – UnderhoodService

Main Navigation

Advertisement
Social Connect
Resources
Our Brand Family
Underhood Service Logo
Technical resources to help diagnose and repair engine-related service issues.
Engine

Tech Tip: Oil Leak Repair for 1990-’93 4.0L Ford V6 Engines

The 4.0L Ford V6 has been a problem engine for oil leaks for years. This engine has been used in the Aerostar, Explorer and Ranger pickups. The most common oil leak on 1990-'93 4.0L engines is often diagnosed as a rear seal leak, but in most cases, the problem is usually found to be the rear of the oil pan gasket.

Underhood Service Staff Writers
By Underhood Service Staff Writers
Published:

The 4.0L Ford V6 has been a problem engine for oil leaks for years. This engine has been used in the Aerostar, Explorer and Ranger pickups.
figure 1
The most common oil leak on 1990-’93 4.0L engines is often diagnosed as a rear seal leak, but in most cases, the problem is usually found to be the rear of the oil pan gasket. Since 1990, when the 4.0L was first introduced, Ford redesigned the gasket twice and even the oil pan casting to eliminate the leaking issue.

Related Articles

The following installation tips from Canada Engines should help to prevent this costly and aggravating oil pan gasket leak.

The ’90 to ’93 gasket set will include a plastic wedge seal that goes into a groove in the main cap. The diagram (Figures 1 – 5) explains the steps to take for a successful installation.
figure 2 - the 1990 to 1993 model years use gasket a along with the wedge seal b (figure 3) on the rear main cap.
Source: Canada Engines LTD.
figure 3 - use gasket a (figure 2) along with the wedge seal b on the rear main cap.figure 4 - the oil pan was redesigned in 1994 and so was the gasket shown c. the wedge seal is no longer used because its shape is built into the gasket. silicone is still necessary across the main cap and in the cavities between the cap and the block.Figure 5 - The oil pan must be aligned with a straight edge to the back of the block before it is torqued down.


You May Also Like

External Engine

Alternator Testing For No Charge Conditions

Many alternator problems turn out to be nothing more than a bad connection at the alternator or a bad wiring harness.

Andrew Markel
By Andrew Markel
Andrew Markel is the director of content for Underhood Service magazine. He has been with Babcox Media for 20 years. He is a technician and former service writer and holds several automotive certifications from ASE and ­aftermarket manufacturers.
Published:

If only battery voltage is present at the battery on a running engine, does this mean the alternator is “bad?” No, it does not. It only means that the alternator is not charging, but does not reveal why. Therefore, it does not point to a faulty alternator. All too often, the alternator is condemned by technicians due to this test alone. The cause could instead be a module that distributes the power to the vehicle and regulates the alternator.

Read Full Article

More Engine Posts
Understanding Coolants

All-season coolant used inorganic acid technology and worked great for almost 30 years.

By Andrew Markel
Ignition System Do’s and Don’ts

Why do ignition systems give technicians problems when diagnosing ignition-related misfires? The answer is that some technicians use tests that might give inconclusive results or do damage to the coil or drivers inside a module.

By Andrew Markel
Tools To Service Serpentine Belts

Servicing the serpentine belt on some vehicles is a tough task.

By Andrew Markel
Battery Charging and Diagnostics

Here are six tips to use when diagnosing a vehicle with a dead battery. 

By Andrew Markel

Other Posts

Why Do Timing Chains Stretch?

As the timing chain wears, it can change the timing of the camshaft and crankshaft.

By Andrew Markel
Carbon Deposits and Direct Injection Engines

The primary cause of these problems is that fuel and added detergents are not hitting the back of the intake valves.

By Underhood Service Staff Writers
Acura Turbo Engine Service

It is important to check the operation of the solenoids that control vacuum to the actuators.

By Andrew Markel
Subaru EJ25 Head Gasket Problems

Most of the EJ head gasket failures occur around the 100,000-mile mark and start as a slow oil or coolant leak.

By Andrew Markel