My 2016 (that's 5 years + 4 months ownership, in my case) is throwing 3516-11. Engine power is derating because it can't figure out how to apply the DEF. I've cleaned and flushed the tank and replaced with new, clean DEF. My dealer indicated that if the above didn't remedy the issue, then a new manifold ($$$) is needed as the sensor is not sensing. I do get an accurate tank level reading. The warranty timing is typical of my luck. Are there other remedies? Is the manifold a part I can replace myself (amateur mechanic)? They couldn't have made it any easier to get to. Getting the machine transported is a logistics challenge for me that I'd like to afford, unless such repairs require special skill/tools.
Is this code for def quality? If so then if everything you did didn't fix it then the next step is the manifold. And yes you can do it yourself. Unless the machine goes into full derate. Then the dealer will need to clear that code after the manifold is replaced. Just a few tips. There are two coolant hoses going to the manifold. So you will need heater hose pinch pliers if the hoses are rubber. Also def has shelf life of roughly 6 months at room temperature. The hotter the faster it will degrade. You may want to get a def refractometer. And I know this works with other makers. I just don't know if this will work with cat. Drain out the def. Then key on engine off and refill with new def. This will trigger a refilling event and it will check the quality of the def. If the machine is not in full derate and the sensor is working with good def. Then it will clear the code itself.
Try this thread. It started out as something else but ended up addressing the DEF system. HeavyEquipmentForums
Thank you both very much. Very helpful info. @Paul , yes that is the DEF quality code. Not in full derate. I feel like I am playing with fire just by firing it up to troubleshoot. Now that I've read the article link to by @Nige , I didn't actually flush the def tank. I only drained it, "rinsed it", and refilled it. My next step, if I were to be forced into a situation where replacing the manifold were the next step, was to do what that procedure instructed. "What would I have to lose?", I asked myself. I used my machine heavily all spring and summer through August, then shut it down and it sat until Thanksgiving, with about 1/4 full of DEF. With this being my first DEF lesson, I'll pay more attention to that. After seeing what DEF looks like after it dries, I'm sure what is all over the parts of that heater and other parts is a bunch of crusty crud. They need to make the DEF tank easier to purge for us farmer types. A couple more questions... @Nige The procedure mentions some other procedures. Of interest to me is Disassembly and Assembly, "Manifold (DEF Heater) - Remove and Install". I'm pretty sure I can wing it. Do you know if operators can get a hold of these pubs from CAT? @Paul Council Pinch Pliers...I presume coolant is going to go everywhere if I'm not ready? The procedure linked by Nige indicated draining, at least partially, the coolant system. Yuk. I might make some plugs the stick in the ends...
I thought that rang a bell. I remember looking for that in respect of the linked thread. The procedure referred is not in the system - they obviously haven't written it yet or have forgotten to write it. Attached is a procedure for an articulated truck that might give you some general guidelines. My opinion is that you should replace the DEF filter in the manifold as a minimum once you have it apart. It has its own separate Part Number - 507-9126. Note the comment about ONLY ever using distilled water to clean the DEF tank and fittings. IMO you should defer to the experience of guys such as Paul who work on these TIER 4 engines all the time.
Just to close this out for future lurkers, this issue was resolved by replacing the DEF manifold--$2800. I do not consider myself a competent mechanic but was able to get the machine back into operation. For me, taking the machine to the dealer would be a major work of logistics, so this was very worth it. They couldn't have put this part in an easier place to service. Prior to ordering the replacement part, I made 2 attempts at flushing the DEF system--the 2nd being extremely thorough and aggressive. I also replaced the filter. The tech at my dealer also suggesting checking the electrical connector for crusty buildup of DEF. It wasn't. I'm not even sure how that would be possible. For me, the biggest challenge was not knowing the mechanics of the header. What holds the header in place? Are the ports for the ELC and DEF fixed in place? What kind of abuse can they handle to remove the hoses? Those white clips for the DEF ports? Are they fragile? The ports are durable and pivot freely--kind of like PEX plumbing fittings do. This makes getting the rigid hoses on/off much easier. The DEF ports were easier to understand after I struggled to get them to release. I knew the white clip either needed to be compressed or expanded. The curled lips looked like they were made to be compressed, but this seemed wrong. But compressing the clip (squeezing the top of the U together) released the port. They actually endured a mountain of manhandling--on a very cold day. I just needed to have the radiator ports free so the entire group of hoses could release. I didn't drain the radiator, and didn't have hose pliers. I had some PVC parts laying around the shop and made a pair of plugs to jam in the hose as soon as I pulled them off. I knew fluid was going to jut out of both the open port and hose, so I got both sides nearly free and went at it really fast. I only had a small but of fluid to wipe up. The head is held on to the tank with a tabbed mechanism with tabs and slots. It releases by turning CCW about 30 degrees or so so the tabs of the header align with the slots of the tank. The header has rigid standouts at several places around the edge of the lid. I used an open-faced wrench and hammer to light tap on alternating sides until it free'd up. Installation was the same method.