Difference Between 4.0 OHV and SOHC
Article by Mark Trotta
My first Sport-Trac (2001) had a 4.0 OHV engine. My current Sport-Trac (2008) has a 4.0 SOHC engine. So I'm familiar with both versions.
The 4.0L SOHC motor (often pronounced "sock") was introduced in 1997 in the Ford Explorer, alongside the original 4.0 OHV version, which was phased out about 2000. The SOHC V6 was also offered in the Ford Mustang from 2005 through 2010.
The main difference between the two is that in a SOHC engine, there are two camshafts, one on the top of each cylinder head, and the valves run directly off the camshaft. It uses a jackshaft to drive a timing chain to each cylinder head.
An OHV engine has a conventional drivetrain; one camshaft operating push rods, rocker arms, and lifters.
How Can I Tell Which 4.0 Engine I Have?
Ford cars and trucks fitted with the OHV 4.0 engine will have the letter "X" as the eighth character in the VIN.
A 4.0 SOHC vehicle has the letter "E" as the eighth character in the VIN.
The easiest way to tell is the engine cover will say "SOHC" on it.
*********************
Oil Filter Differences
The 4.0 OHV engine takes a different filter than the SOHC motor. Auto parts stores often get this wrong, and the two filters do not interchange!
For the SOHC motor, the factory filter is a Motorcraft FL820S.
For the OHV motor, the factory filter is a Motorcraft FL1A.
*********************
Engine Oil Capacity
Both engines have the same engine oil capacity, which is five quarts with filter change. Recommended viscosity is 5W30 for either.
Read: Best Oil For Daily Driver
*********************
On my 2008 Sport-Trac, I change oil and filter more frequently than the recommended 7500 miles, usually between 5K to 6K miles.
Why change the oil sooner than recommended?
One reason is, if your daily commute involves a lot stop and go driving, it's harder on the motor. And if you live in a warm climate, summers can be pretty tough on engines, especially in traffic with the A/C on.
Another reason for changing oil sooner is if you make a lot of short trips, which doesn't give the engine a chance to reach it's proper operating temperature. This could result in condensation (moisture) inside the crankcase.
*********************
Check The Dipstick
Common signs that your oil may be due for a change is if it looks dark or milky on the dipstick.
Most newer vehicles will display a message on the dash at the proper oil change service interval. Either 'ENGINE OIL CHANGE DUE' or 'OIL CHANGE REQUIRED' will appear in the display.
*********************
Replacement Oil Drain Plug
Even if you wait until the 7,500 mile interval, by 100,00 miles your motor's seen at least 13 oil changes. How's your oil drain plug and washer look?
To ensure no leakage, replace it every 30K miles. The Ford part number is 9L8Z-6730-A and it's designed with a built-in washer.
TIP: Buy a spare oil drain plug before you need it. And don't over-tighten.
*********************
Ford 4.0L OHV Engine Specs
- Displacement: 245 cubic-inches (4009cc)
- Engine Bore and Stroke: 3.95" × 3.32"
- Compression Ratio: 9.0:1
- Number of Valves: 12
- Horsepower: 160
- Gross Torque: approx 225 ft/lb (depending on model)
This engine was part of Ford's Cologne V6 line. Other displacements included 1.8, 2.0, 2.3, 2.4, 2.6, 2.8, and 2.9 litre versions.
*********************
Ford 4.0L SOHC Engine Specs
- Displacement: 245 cubic-inches (4009cc)
- Engine Bore and Stroke: 3.94" × 3.31"
- Compression Ratio: 9.0:1
- Number of Valves: 12
- Horsepower: 160 to 207 (depending on model)
- Gross Torque: 225 to 238 ft/lb (depending on model)
Timing Chain Problems
Due to the SOHC engine's unique design involving both front and rear timing chains, timing guide replacement often requires engine removal to gain access. After 2002, updated cassettes and tensioners were installed from the factory.
*********************
High Mileage Engines
After 150,000 miles on my 2008 Sport-Trac, I noticed five full quarts of old oil were not draining out of the motor. This was easy to see, as I pour the old oil back into the 5 quart jug it came in.
Looking underneath the engine, I saw no leaks, which confirmed that the engine (like most high mileage engines) burns a little oil. This is OK and normal, but you need to check oil level periodically, and add if needed.
*********************
Related Articles: