Marc Posted December 27, 2019 I have a new 2019 nv3500 cargo 5.6l high roof I'm at 2000 kms . The first week I had it it was great , I didnt reset the trip odometer but the van had 230 kms on it and it was at over 800 kms when I next filled it up so I'm guessing I got about 600 kms per tank, i was pretty happy about that. Van was loaded with all my tools. After the first week I started noticing a knocking sound, more of a clicking really, I just assumed it was a bad pulley run by the accessory belt , since i dont have a local nv dealer close to me and since I needed the van i kept using it . After a couple of gas fill ups I knew something was wrong , hoping maybe because u can literally see the gas gauge drop . I started keeping a record and I was getting 240 to 260 kms per tank ... I started trying to drive it easier, started having my crews pick up the materials in our other vehicles to keep a consitant weight (approx 600 lbs with shelves and tools ) no ladder rack) and it stayed consistent around 240 kms . I brought it in for service , after a week and a half they changed both the air conditioning compressor and the fan clutch and can not find the source of the knocking . The knocking goes away with the accessory belt off . I think the fuel consumption and the knocking are related but all their diagnostics show the engine performing 100 % ., they are convinced it's just a minor issue that they will get to the bottom of and want me to keep a milage log to show the fuel consumption . I dont completely disagree but I'm hoping there's a bigger issue here as this thing is a fuel pig. I was hoping someone here may have had a similar issue they could share with me , and someone with a 5.6l high top who could share has milage info to see if this is normal or not.. Quote Share this post Link to post Share on other sites
radin2son Posted December 27, 2019 Assuming the conversion is correct, 600 k or 372 miles on a tank seems too high. The few times I pushed 360+, I was looking for a gas station. 3 gallons or 11 liters left. Could there be something wrong with the odometer? Average V8 mpg is around 12 mpg or 19+ kpg. Some high top cargo users reported as low as 9 mpg or 14+ kpg. Quote Share this post Link to post Share on other sites
Marc Posted December 27, 2019 It may have been less then my estimated 600 kms for the first tank , it could have been mid 500' s (340 miles) as the odometer was in the 200's when purchased and my first tank was in the 800's . .. I should have converted to miles ... I'm getting right around 150 mile out of a 21 gallon tank which is 7.1 mpg . I'm fortunate that my normal cargo is fairly light , I bought the 3500 because I tow a dual axle dump trailer with loads upto 2 tonnes . I'm not using my has milage with the trailer here , its ridiculous when I tow but that's understandable ..it only happens once a week or so. 1 radin2son reacted to this Quote Share this post Link to post Share on other sites
Marc Posted December 27, 2019 Good idea about the odometer though... I will get one of my other crews to follow me to a job site and compare ! 1 radin2son reacted to this Quote Share this post Link to post Share on other sites
radin2son Posted December 28, 2019 (edited) 7.1 mpg is the worst I can recall. Not that it matters, it’s a 28 gallon tank. It still comes down to gas in and miles driven. Another thing to check, does your tank fill to capacity? The nozzle can cut off way to soon. This appears to be a NV filler tube issue. There are times when I have to hold the nozzle to keep it from clicking off. Another would be to check the gas gauge and pump. Hope it is a simple fix. The knock/click is another issue... Keep pushing the dealer on this. Edited December 28, 2019 by radin2son Quote Share this post Link to post Share on other sites
