2003-2007 Ford F-250 6.0L V8 Powerstroke. 2003-2007 Ford F-350 6.0L V8 Powerstroke. 2003-2005 Ford Excursion 6.0L V8 Powerstroke. Leaking oil coolers and cracked cylinder heads often contaminate the cooling system with engine oil or diesel fuel causing the reservoir to soften and swell - often to the point that the cap cannot even be reinstalled.
