2025 T880 X15 Driver said inlet air restriction was at 30 when loaded. We changed the filter (Filter was barely dirty and was changed 1 month before that). Driver said restriction was better, but still high around 17. We took apart whole inlet side and didn't see anything abnormal. What else should we check?
17” of water restriction for a new filter setup (inner & outer elements) is about right in my experience. Certainly in the ball park. Question: Even though the elements that were removed were not apparently dirty is there any chance they might have been a bit damp.?
I didn’t see any moisture
The moisture probably wouldn’t have been visible. Usually you can tell the difference in weight if you hold a brand new element in one hand and a used one in the other.
They felt about the same
Gents. The Kenworth dash instrumentation indicates %. 30% is normal. We are getting units of measurement mixed up. 30 inches H20 vs 30%.
I'm sorry, I thought it was H20, but it is %. Why/how is it normal to have 30% restriction? Is it just because of the high vacuum being pulled from acceleration? I drove both the problem truck and its sister truck unloaded down the interstate and they read the exact same numbers; boost, air restriction, fuel filter restriction, torque %. The driver in the sister truck has no complaints. I will try to test drive it with a load tonight to try to duplicate the issue.
Colour me surprised also. I'm used to filter resriction being measured in inches of water.
The driver display isn’t very accurate or consistent. If you have a concern, connect a Magnehelic gauge and get some real numbers to work with.
A few days later the truck came back with a def light on the dash. Ran a forced regen and that seemed to fix everything.