Loud "air escaping" noise, then Check Engine light

[MikeGriffin]

Traveling down the interstate the other day, I began to notice a loud hissing noise, kind of like air escaping, as people passed me. It seemed as though the noise might be coming from my coach because I didn't hear it unless the sound was bouncing off of the passing vehicles. When I pulled over to check, I couldn't hear anything. However, as soon as we were back on the road it started up again.

After quite a few miles, the check engine light came on with a small beep and the LCD display showed "Check Engine!". We pulled over and got instructions from Freightliner to view the engine fault code, which read "SPN 102 FMI 18 SA 0". I was told that it meant that air was not getting to the turbo and that I could keep driving until getting it repaired, but it may be a bit slower because the turbo wasn't getting enough air. Likely a loose or broken hose.

So we went to a nearby Cummins service facility. Sure enough, it was the Charge Air Cooler Hose. It looked as though one of the clamps holding it in position had "helped" it get tear over the past couple of years.

We ordered and they installed a new hose and all is well. I'm very aware that this topic has been discussed before on this forum, but wanted to help others by providing a clear explanation as to how the problem is first detected and a little bit about the probable cause.

The photos show the Hose (it's orange) in the lower left side of the engine compartment and a close-up of the tear. I also included the sticker that came with the new one so that everyone could see the part number.

[Dutch Star Don]

Glad you found the issue so quickly. Kind of unusual that the hose tore like that unless the clamp was seated over the hose and over the tubing.

[Jim_L]

I previously owned a 2008 KSDP that had a similar issue. Usually black exhaust when the hose came off. On that coach, the metal tubing that is connected with the hose was not lined up and eventually the hose would pry off. Solution was to loosen all hoses (there are a few) and line the tubing up better and then use two hose clamps on each end each hose. I now have a 2014 DSDP and two hose clamps are used. I might suggest that you take a close look at yours and determine whether the alignment of the connected hose is proper. The picture suggest that they are not and the resolution is to loosen all hoses and retighten after lining them up better.

[Dav L]

wonder if the nipple at the end of the steel pipe is a bit sharp and due to the engine rocking on it's motor mounts, eventually the pipe sawed thru the hose.

Next time under the hood I would just take a quick look at the motor mounts to see if it's torn. Unlikely, but one of the possible causes. You might have to lift the engine up a bit (only just enough) with a floor jack to see if the mount is separated.

[lostinfla]

Glad it was a simple fix Mike. Another reason to carry duct tape.

[Norm Mac]

Okay Mike, Now you have me paranoid! I had to run out and check mine.

[RJ51]

Thanks Mike for that post, glad it was an easy fix. I will keep an eye on mine.

[lostinfla]

Originally Posted by Norm Mac

Okay Mike, Now you have me paranoid! I had to run out and check mine.

Ditto!

[dp7]

Surprised that FL said to keep driving. Wouldn't this allow unfiltered air to enter the turbo?

[twinboat]

Originally Posted by dp7

Surprised that FL said to keep driving. Wouldn't this allow unfiltered air to enter the turbo?

No, the break is after the turbocharger, that is always pushing some air, and always under positive pressure.