View Full Version : Resonator

05-21-2015, 03:36 PM
Is it very noticeable to tell if the resonator fails? Does the seam open up a lot? My 2004 loose boost randomly while going uphill on the interstate going 70 mph. Will still go 60 or so with the pedal floored and I can't hear the turbo whistle. Shut it off and restart and everything fine for some time. Thanks.

05-21-2015, 03:56 PM
These are classic turbocharger resonator failure/cracked upper joint symptoms.
But it could just as well be one of the turbo hoses or even a leak or crack in the
charge air cooler (intercooler that resides in front of your engine coolant radiator).
You can remove the turbo resonator and have a look at it.
Or simply change it in favor of one of the Dorman knockoffs (made in China, but less
prone to failure than the OEM MB units).
Or you could upgrade to the Riordanco resonator eliminator:
In any case, if you had a Scan Gauge II or similar, you would be able to monitor your
turbocharger output pressure (Manifold Absolute Pressure or MAP) and see if your turbo
plumbing is capable of handling the full ~36 PSIA turbo output.
Pushing the throttle to the floor, to get up those uphill grades is probably NOT the best idea.
Why not simply downshift to 4th gear, let the RPM come up into the best power range (2700-3150 RPM)
and then you may be able to run right up the hill without suffering a boost/map pressure fault, whether
it be the turbo resonator, a turbo hose or hose joint, or something else in the boost system.
Hope this helps,

05-21-2015, 04:32 PM
I was leaning towards the resonator. But wanted input from guys that know more then me about sprinters. Is it easy to visibly see if resonator is cracked?I crawled under it to look and couldn't noticeably see a problem

05-21-2015, 05:01 PM
Normally you can see the cracked resonator better from the top (might need to remove the shiny silver heat shield over the top RH side just in front
of the turbo).
Do some searches here on "cracked turbo resonator" or "cracked TR" and you will see many examples of how the top of the resonator cracks on the
glued joint between the top and the body of the resonator.
Hope this helps,

05-21-2015, 05:15 PM
Look for traces of oil on or around the seam as this is a good indicator of a failed resonator. A replacement Dorman resonator is available on amazon for ~$30, but you should install an OEM O-ring and toss the Dorman O-ring, because it doesn't hold up under the heat and pressure.

05-21-2015, 08:57 PM
Ok. There is oil on the seam. I'm gonna replace the resonator. Thanks.

05-22-2015, 08:51 PM
I put one of these in:


You still have to replace the Oring every once in a while but no chance the main piece splitting apart. Easy to install and have not noticed a real sound change.