One of the easiest way for GM/Dealer to get around warranty claims on a diesel is 'visible corrosion due to water'. I work with construction companies that literally have hundreds of 6.5's and Duramax service verhicles. In case after case, they had been writing multi-thousand dollar checks for pump and system repairs due to disallow of warranty due to obvious water damage/corrosion. Not that the component was damaged from water; in most cases it was just a physical, unrelated failure. However, free water is the number one cause of warranty disallow. Soooo, if one wants to address the #1 cause of warranty disallow in addition to providing all the other benefits that a high quality fuel additive can bring...??? One recent trip to a local GM service center had 3 trucks sitting out back as the $3,000+ estimate for repairs for each was beyond each owner's budget; the trucks had been there for several weeks. All three trucks were under the mileage/time warranty limit but all three had fuel system corrosion..
Since the EPA pronounced that diesel fuel bottom water is hazardous, many fewer operations are drawing bottom water off diesel fuel storage tanks. Both free and entrained water is now present in much higher quantities than in years past. As we have seen in fuel test after fuel test, the Stanadyne water separator is relatively ineffective (some say totally) at removing water. Even with a de-emulsifying fuel additive, the minute the vehicle starts up and begins moving, that separated water goes right back into loose emulsion and will not be removed by the water separator. Now, when the vehicle shuts down again and the loosely emulsified water that has passed by the water separator has time to sit, yes, it will once again separate out, settle and proceed to cause corrosion, rust and on start-up potential damaging results..
George Morrison, STLE CLS