Chevrolet / GMC 6.5L PMD Cooler
The PMD story, and why you need a cooler.
The PMD (pump mounted driver) or also known as a FSD (fuel system driver), has been a major problem for Chevy / GMC 6.5L diesel owners since its introduction on the 1994 6.5L electronically controlled DS4 fuel injection pump. The PMD is a solenoid pack that builds up heat and uses the injection pump and the fuel running through it to absorb that heat. The injection pump is in the valley of the engine between the cylinder heads and the heat produced by the engine is also absorbed into the injection pump. In some situations the fuel going through the pump cannot adequately remove the heat to keep the PMD functional. Once the engine begins showing symptoms of stalling, hesitating, most likely the PMD is failing and the problems will only get worse.
Be sure to look closely at other so called "coolers" out there. Many do not have the cooling capacity that ours does and are little more than remote mounting brackets that only relocate the PMD away from the engine heat, but do nothing to deal with the heat made by the PMD.
Buy a PMD Cooler Now!
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