Yes, it is definitely necessary, if you’ve had the fuel system open for any length of time. For example, if you’ve replaced or rebuilt a head, replaced fuel lines, injectors, etc. For a filter change, I’d agree, it’s not completely necessary. Keep in mind, the dt466 and the C7 use a HEUI pump to supply high pressure to the injectors. The Mercedes 906 uses individual unit pumps, one per cylinder. In either case, HEUI or unit pumps, having an air gap in the fuel system causes the pump to be run “dry” momentarily, causing unnecessary wear to the pump’s internal components. So, though it’s not completely necessary, you should always prime a diesel engine, even if you’re just changing the filter.
Very interesting, Not familiar with this engine and I have one No start, we replaced fuel filter,the screen got loose, it start right up after service with no prime, we let it idle 15 minutes, but after 12 hours, truck didn't start , driver tryed several times, he burned started, we put a new starter in 24 hours and we notice smaller sfilter scream was kind little leaking fuel, we fuel it all filter as they all got empty, we tryed to start again, it didn't start either, could this Sistema might need to be primed, ? Is other way to prime it if we don't have your tools???
@@1HSYURIDIA Mike, any leak in the fuel system, that is physically above the fuel tank (which is most of the fuel system) will allow air into the system, causing the fuel to drain back into the tank when the truck is turned off. It’s like when you put a straw into a glass of water, put your thumb over the end, and lift the straw full of water out of the glass. The water stays in the straw, as long as your thumb is covering the top of the straw. But, take your thumb off the top of the straw, and gravity makes the water fall out of the straw. Same principle applies here. That leaky seal on the screen filter housing that you mentioned, is the same as you taking your thumb off of the straw. You’ll need to fix that leak first. But, then yes, you’ll need to prime the system. You can buy a priming pump. They’re similar to a fruit sprayer. They’re just metal tanks, that you put fuel into and pump up, to produce enough pressure to prime the system. There are cheaper ones out there, but I’ve attached a link so you can see what they are. I simply made the one used in my video, because I couldn’t get one locally, and needed the truck back on the road same-day.
