Tony302600 Posted July 26, 2007 Share Posted July 26, 2007 Alright, 2003 F-550, 98,000 miles, towed in, 9 qts low... no oil leaks, no blue smoke, no oil sticker, dirty air filter, runs awesome after the 9 qts did all diag /forums/images/%%GRAEMLIN_URL%%/scratchhead.gif /forums/images/%%GRAEMLIN_URL%%/shrug.gif Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted July 26, 2007 Share Posted July 26, 2007 Sell the owner a full service. It has obviously been neglected. The 7.3L will stop running when it gets low on oil, typically 7 quarts plus. When the engine is low on oil the crankcase can run low during operation as the oil in the engine is returning to the pan slower than the engine is using it. Once the level is low, the oil pump can start sucking air and the resulting loss of high pressure oil will cause the engine to stall. Quote Link to comment Share on other sites More sharing options...
Tony302600 Posted July 26, 2007 Author Share Posted July 26, 2007 i know that when they get low taht they shut off....thats happened to me tons of times when the o-rings leak on the high pressure pump. I was checking if anyone found some messed up concerns like this one before. Verdict is neglect on this one i guess....ComEd and their damn bio-diesel 6.0's and neglected 7.3's. Quote Link to comment Share on other sites More sharing options...
blown99 Posted July 27, 2007 Share Posted July 27, 2007 How about an injector o-ring going bad. If the middle o-ring goes bad, high pressure oil will be forced into the fuel system and either burned as fuel or returned to the filter housing. Ususally the engine does not smoke or have a performance complaint. Quote Link to comment Share on other sites More sharing options...
Bruce Amacker Posted August 1, 2007 Share Posted August 1, 2007 How about an injector o-ring going bad. If the middle o-ring goes bad, high pressure oil will be forced into the fuel system and either burned as fuel or returned to the filter housing. Ususally the engine does not smoke or have a performance complaint. Let's clarify this as to not confuse others. I see you're a Diamond IH tech, but the T444E is a bit different than the 7.3 PSD in this area. The T444E uses a fuel system very similar to the early Gen 1 PSD's. Generation 1, '94-97: A leaking center o-ring usually generates a "huge oil consumption" complaint, because the oil is allowed to travel to the fuel tank from the HP oil galley via the center o-ring and the fuel return hose on the head. This effectively pumps the contents of the oil pan into the fuel tank. These are usually diagnosed by sampling the FF to find black oil, or the oil level going very low to the point of a performance complaint. Gen2, '99-03: These engines lack the fuel return hose from the head to the FP regulator seen on the Gen1 trucks, making this fuel system returnless from the head. (It still does have a return line from the FP regulator on the FF, though) When the center o-ring leaks on these, the complaint is usually cold smoking and misfire. This is because the HP oil overcomes the fuel pressure in the fuel galley and oil now becomes the fuel to one head. Because of the viscosity of 15w40, it does not vaporize in the cylinder when cold and causes a misfire and blue/white smoke complaint. The cust usually complains more about the engine when cold then warm, partially because 15w40 gets thinner when hot, and maybe the center o-ring seals better after then engine warms up. Sometimes the oil will overcome the check valve in the FF to head line and leave black oil in the FF. Good Luck! Quote Link to comment Share on other sites More sharing options...
Tony302600 Posted August 1, 2007 Author Share Posted August 1, 2007 Jesus Bruce thats awesome. Totally going to help me when winter comes. I basically did a oil change, fuel filter and air filter and shipped it. Quote Link to comment Share on other sites More sharing options...
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