Radiator for GMC Jimmy (1970-1972) 4.1L 4.8L

High-Efficiency 3-Row Aluminum Crossflow Radiator for 1970-1972 GMC Jimmy (K5 Chassis)

What it Does: The 3-row aluminum crossflow radiator replaces the heat-fatigued factory copper-brass heat exchanger on the 1970-1972 GMC Jimmy to dramatically maximize heat dissipation efficiency and eliminate boiling during heavy-load operation.

The Stock GMC Jimmy Thermal Transfer Bottleneck

Factory cooling systems in the 1970-1972 K5 Jimmy rely on aged copper-brass cores joined by lead solder. Over decades of thermal cycling, these original units suffer from internal tube scaling, galvanic corrosion, and separated fins that drastically inhibit conductive thermal transfer. When crawling at low speeds or pulling sustained grades, the factory radiator cannot shed heat fast enough from the high-torque 250 ci (4.1L) and 292 ci (4.8L) inline-six powerplants, resulting in heat soak, coolant boil-off, and potential head gasket failure.

The Engineering Solution

This heavy-duty upgrade utilizes a high-density 3-row aluminum crossflow core measuring 26.26 x 16.06 x 2.00 inches. Fabricated with fully TIG-welded aluminum end tanks rather than failure-prone crimped or soldered joints, it resists pressure spikes and elevated operating temperatures. The crossflow architecture channels coolant horizontally across high-surface-area louvered aluminum fins, significantly speeding up heat rejection before the fluid returns to the block through the 1.75-inch outlet.

What's Included

• 1 Radiator
• 1 Radiator Cap

Technical Specifications

Compatibility

• 1970-1972 GMC Jimmy 4.1L (Fits inline-6 models utilizing a 26.5-inch wide core)
• 1970-1972 GMC Jimmy 4.8L (Fits inline-6 models utilizing a 26.5-inch wide core)

Frequently Asked Questions & Fitment Warnings

Does this fit the K5 Jimmy?

Yes, this is a direct fit for the 1970-1972 GMC Jimmy equipped with the 4.1L or 4.8L inline-six engines using a 26.5-inch wide core mounting configuration. It does not fit V8 models or applications configured for narrow-width core supports without bracket modification.

Is professional installation recommended?

Yes, direct replacement mounting aligns with factory locations, but professional installation is advised to guarantee proper coolant burping and hose clearance.

The GMC Truck Standard

Engineered for rugged vintage truck use, this heavy-duty cooling assembly provides the thermal headroom required for low-RPM rock crawling, remote trail recovery, and prolonged highway hauling without temperature creep.