Engine Block Heater for Jeep Cherokee (1987-2001) 4.0L

Cold-Weather Freeze Plug Engine Block Heater for 1987-2001 Jeep Cherokee (XJ)

What it Does: The Zerostart Engine Block Heater warms engine coolant directly inside the block of the 1987-2001 Jeep Cherokee to eliminate dry cold-starts, reduce starter draw, and deliver rapid cabin heat in sub-zero environments.

The Stock Jeep Cherokee Cold-Start Vulnerability

The cast-iron AMC 242 4.0L inline-six possesses substantial thermal mass. During sub-zero winter temperatures, thick 10W-30 engine oil resists rapid hydraulic flow to critical top-end components, including the flat-tappet camshaft, lifters, and pushrods. This cold-start boundary friction compounds starter motor load, drains factory battery reserve, and keeps the engine in rich, inefficient open-loop fueling far longer than necessary, accelerating internal cylinder bore wear.

The Engineering Solution

Engineered by Zerostart/Temro under part number 3100072, this 600-watt, 120-volt immersion heater integrates straight into the cooling jacket via a standard 2-inch freeze (core) plug port. By submerging the heating element directly into engine coolant, natural convection circulates heated fluid through the entire cast-iron cylinder block and cylinder head. The package includes a weather-sealed, detachable power cord, providing consistent heat soak down to -40°F to guarantee instant turnover and lower cold-start tailpipe emissions.

Technical Specifications

Compatibility

• 1987-2001 Jeep Cherokee (XJ) with 4.0L Inline 6-Cylinder Gas Engine
• Note: Does not fit 2.5L 4-cylinder, 2.8L V6, or diesel variants.

Frequently Asked Questions

Does this fit the XJ Cherokee?

Yes, this is a direct fit for the 1987-2001 Jeep Cherokee equipped with the AMC 242 4.0L engine.

Which engine port is used for installation?

It presses directly into a 2-inch engine block freeze plug port; drain coolant completely before driving out the factory core plug and installing the unit.

The Jeep Durability Standard

Engineered for brutal winter duty cycles and extreme overland cold, pre-heating your iron 4.0L preserves oil film strength, protects valvetrain metallurgy, and ensures your trail rig fires on the first turn of the key.