EGR valve cleaning

2012 Volvo VNL D16- 940,000 miles

Can I clean the EGR valve by removing the dog house and getting to the actuator from behind it? I'm thinking that it is stuck open, and even if not, it would be good to get it cleaned. I've been reading that the bolts that connect the valve to the manifold are prone to breaking, so I'd like to avoid removing the whole valve if I can. When I get home, I can take a shot at cleaning the whole system.

About a month ago, I got a code for EGR flow high that ended up going away after an hour of driving or so. I didn't notice anything weird about how the truck drove. Last week while driving, the truck requested a regen due to high soot levels. About 10 miles after, it went to the next level of derate, and then after 10 more it went to high derate. I stopped and reset everything and performed a forced regen with the OTR performance tool. After about 40 miles of driving, the same thing happened. There is a sweet spot where the soot level will stay right before it requests a regen, but any kind of grade or traffic will raise it. Usually running hot going up mountains will lower the soot levels, but now it increases it.

Sometimes the boost levels will fluctuate when trying to maintain a set speed. When it does happen, it will bounce up and down +/- 5 PSI. Under constant throttle like pulling up a grade, it will delay only at first and then keep a pretty steady level of boost around 30 PSI. There are no weird noises or anything, and it doesn't always occur.

There are no codes showing up, so I don't know if I should replace any sensors or which ones. Exhaust temperatures while driving seem pretty high, like 700F, but coolant(190F) and oil(210F) temperatures are normal. I hardly ever have to perform a parked regen and don't idle very much, so I don't believe the DPF is the cause. I will try to clean the EGR system first, then move onto cleaning and inspecting the DPF. The 7th injector appears to work, since I can hear and feel it during a regen, but I will remove that and clean it as well. The EGR cooler was replaced at about 800,000 miles along with the 7th injector, but the valve hasn't been touched since I've owned the truck.

Am I on the right track here, or is there something else I should be looking for? Would I be better off having the diesel force cleaning done on the EGR system than trying to mess with removing bolts that have probably never been touched in almost a million miles?

 

After watching a video, it appears I won't be able to get to the part I need to without removing the valve. I guess I could push and pull the plunger and hope it unsticks something, but I won't be able to spray any solvents or anything where it matters.

 

The venturi tube looked kind of hard to get to on the D16 since it's under a coolant hose and the overflow tank, so I was waiting to get home to pull that apart. I also plan to remove the flex pipe between the DPF and SCR box to see if there are any blockages. I haven't taken it anywhere to do any tests yet.

 

I'm pretty sure Nazrisa recommends having it done. I'm not sure if it would help fix my problem, but I do believe most of my EGR components are due for a cleaning of some sort.

 

I realized yesterday that the mounting bolts for the venturi tube are on the front, so I should be able to get it off without removing the upper coolant hose and overflow tank. I mistook the bolts that hold the sensor down to the pipe for the mounting bolts.

http://www.hhrvresource.com/VolvoDocsGenII/Volvo Engine Manuals/D16/EGR Venturi Tube Replacement.pdf

I've been just taking it easy with the cruise at 55 mph while heading home empty. I forced a regen before I began yesterday so the soot gauge was at 10% or so. It didn't even move from Sacramento until I started to climb up Donner, and it rapidly rose until it hit the A. It's been staying between 90-110% and hasn't requested a regen yet. The turbo is still bouncing around, and I've sprayed the CAC boots and connections, but haven't found any obvious leaks.

I should be home tonight, so tomorrow I will clean the venturi tube and do the rubber glove test to check if the EGR valve is stuck open. If that doesn't help, I will remove the flex pipe after the turbo to see if the DPF is blocked. I'll also remove the one after the DPF to see if I've got DEF crystals plugging things up.

 

I had to cut the hoses to get them off the pipe since they were stuck pretty good. Volvo only sells them included with a kit for $60 each. The V clamp that connects to the mixing pipe on the driver side is like $60 as well. I couldn't get the sensor connector removed because there wasn't enough clearance to pull it apart. I had to unbolt the tube and move it out from the engine a bit in order to make room to remove the sensor plug.

Volvo didn't have a venturi tube in stock for the D16, and the updated kit ($600) that they pulled for my VIN was for a D13. I ended up cleaning out the holes myself. The holes in the tube are straight, so they weren't too bad. The holes on the sensor block were angled, so I used some angled picks to start the holes. I cut a 3" section of cable from the latch for the hood and stuck it in a drill set to counterclockwise, and that made quick work of cleaning all the angles and bends. I hit it with some parts cleaner and scrubbed everything that I could, so now I'm waiting to see if I can get the hoses at Napa or something so I don't have to spend $120. I'll take it for a test drive later today and see if it behaves any differently and I'll update this thread with the results.

 

Couldn't find the parts at Napa, so I spent $120 at Volvo. Cleaning the venturi tube fixed the boost issues, but the soot level still rises too quickly and doesn't go back down. When I perform a regen, the soot level goes down to zero. I'm going to inspect the 7th injector and clean it tomorrow before I inspect the DOC and DPF. When I have them out, I'll probably take them in to get ultrasonically cleaned.