Engine Cooling System

Match the core to your heat load, not to the biggest number.

• A 2-Row 30mm core is correct for a stock replacement on a naturally aspirated four-cylinder, where the factory shroud and airflow were designed around a thin core.
• 3-Row 44mm and 3-Row 56mm cores are the practical range for V8 daily drivers, Jeep XJ/TJ builds, off-road and towing, adding coolant volume and surface area without excessive airflow restriction.
• A 4-Row 60mm core suits LS swaps, boosted engines and heavy-duty diesel trucks, but it only outperforms a thinner core when paired with a high-CFM electric fan and a sealed fan shroud — deep cores are harder to pull air through, so a thick radiator with weak airflow can actually run hotter at idle.

Also confirm you have the physical depth: diesel platforms like the Duramax LB7/LLY and 6.0L Powerstroke have limited stack space between the intercooler, condenser and fan.

Every vehicle-specific radiator lists fitment by year, make, model and engine — for example 1991–2001 Jeep Cherokee XJ 2.5L/4.0L or 1988–2000 Chevy C/K, Tahoe, Yukon and Suburban 5.7L–7.4L V8. These are direct bolt-on OEM replacements; no cutting or drilling is required on the listed applications. Contents vary by SKU, so check the What's in the Box section on the product page before ordering: most direct-fit units ship with the radiator, radiator cap, 1/4-inch NPT drain plug and an S-blade cooling fan, while some heavy-duty diesel applications ship radiator-only so you can retain your factory fan clutch and shroud. If you are running an LS swap or a custom chassis, fitment is determined by core dimensions and inlet/outlet position rather than by vehicle year — measure your available space and hose routing first, or email your build details to support@ievilenergy.com and we will confirm before you order.

In most cases the problem is air trapped in the cooling system, not the new part. An air pocket blocks coolant flow through the heater core and can sit against the temperature sensor, producing a needle that swings erratically and a heater that blows cold — the classic signs of an airlock.

To bleed the cooling system: park nose-high so the filler is the system's highest point, fill slowly through a spill-free funnel with the heater on maximum, idle from cold until the thermostat opens and the upper hose goes hot, squeeze the upper radiator hose to push air toward the filler, open any bleeder screws on the thermostat housing, then cap it, let it cool completely and recheck the cold level — most systems need topping up after the second heat cycle.

If the temperature is still climbing after a proper bleed, work through the rest of the system: a radiator cap that no longer holds rated pressure, a thermostat stuck closed, a water pump with eroded impeller vanes, insufficient fan CFM or a missing fan shroud, or — if you see bubbles in the overflow tank and white exhaust smoke — a head gasket leak that no radiator will fix.

Use the coolant chemistry your engine manufacturer specifies — installing an all-aluminum radiator does not change that requirement. IAT (conventional green), OAT (such as Dex-Cool) and HOAT (common on Ford, Chrysler and European platforms) are all safe with T-6061 aluminum and EPDM seals when used as directed.

What damages aluminum is neglect, not chemistry: once the corrosion inhibitor package depletes, galvanic corrosion attacks the aluminum first. Four rules matter more than brand choice — never mix chemistries (OAT and IAT gel when combined; flush completely if you don't know what was in the system), mix only with distilled water because tap-water minerals scale the tubes and restrict flow, run a 50/50 ratio since going beyond roughly 70% glycol actually reduces heat transfer, and replace the radiator cap along with the radiator — a cap that won't hold rated pressure lowers the coolant boiling point and creates overflow symptoms that get misdiagnosed as a radiator fault. Follow your manufacturer's service interval: roughly 2 years / 30,000 miles for IAT and 5 years / 150,000 miles for OAT and HOAT.

Size the fan by airflow, then by physical fit.

As a working guideline, engines up to about 250 HP are served by roughly 1,500–2,000 CFM (a single 12-inch puller fan), 250–450 HP V8 and LS swap builds want 2,500–3,000 CFM (a single 16-inch or dual 12-inch setup), and anything above 450 HP, boosted, or used for towing should target 3,000+ CFM with a dual-fan shrouded arrangement.

Choose a puller fan whenever there is engine-side clearance — it pulls air through the core and is meaningfully more effective than a pusher fan, which sits ahead of the condenser and typically loses 20–30% of its rated airflow to grille and A/C restriction. For the shroud, the fan should cover at least 65–70% of the core face with blade tips within about 1/2 inch of the shroud so it actually seals.

On wiring, every Evil Energy fan kit includes a 175–185 °F thermostat relay switch and mounting hardware: always power the fan through a relay with an inline fuse sized to its peak amp draw, never off the ignition switch, and give dual fans either two relays or one relay rated for the combined load. Confirm the amp draw on the product page before selecting your fuse and wire gauge.