When draining and filling the cooling system on 2017-2018 Silverado and Sierra models equipped with the 6.6L Duramax diesel engine (RPO L5P), the correct special tools must be used.
In some cases, instead of installing the GE-52098-A Cooling System Pressure Test Adapter on the radiator surge tank, an aftermarket pressure test adapter is being used instead that is not designed for evacuating and filling the cooling system. The adapter is a left-hand adapter that threads onto the top of the surge tank. (Fig. 9)
Fig. 9
The GE-52098-A adapter has two seals and an extended component that close off the vent chamber portion of the surge tank. (Fig. 10) Without these two seals, the adapter cannot properly evacuate the cooling system because air will leak back in from the atmosphere vent cap on the side of the radiator surge tank.
Fig. 10
An aftermarket adapter not designed for this application that doesn’t have these seals (Fig. 11) cannot isolate the vent chamber and the atmosphere vent cap because it does not reach down to the lower sealing area for the cap. As a result, it pulls vacuum against the vent cap. Without a proper vacuum on the system, it will not fill correctly, and air in the cooling system can cause engine damage.
Fig. 11
When draining and filling the Duramax diesel (L5P) cooling system, only the GE-52098-A pressure test adapter should be used. Do not use an aftermarket adapter not designed for this application.
– Thanks to David MacGillis
Updated February 23, 2018
JUST A LITTLE NOTE TO THE GE-52098, THAT TOOL HAS BEEN UPDATED TO GE-52098-A WHICH IS BLUE/SILVER.