These new pump-mounted drivers (PMDs) from Wellman* offer 72° better heat tolerance than the OEM Stanadyne unit. The original Stanadyne PMD was only rated to operate constantly at 185° F... less than the normal operating temperature for the engine! No wonder they fail so often.
* Warranted by Wellman Automotive Products for one full year / unlimited mileage. Stanadyne only guarantees their PMD for 90 days... I wonder why?
It is a well known fact that the PMD is a weak link in the 6.5L fuel delivery system. PMD failures are generally due to excessive heat exposure. For these reasons, we offer an improved version of this part.
The components used in our PMDs are rated to an average temperature of 125°C versus 85°C for the original equipment PMD. Using the temperatures in the chart below, you can see that our PMD components are rated well above the expected operating temperatures while the original parts are not.