Get the Sealants you need to reassemble the engine in your 1999-2003 Ford 7.3L Powerstroke. There is engine specific, all-purpose, and headlight specific RTVs available. Resistant to high temperatures, these RTVs are made from Silicone rubber. You�ll find to brands such as Ford Motorcraft, ACDelco, MAHLE, Oracle, and DEI at XDP.