Voyager Diesel's Hissing & Fuel Waste Points to Turbo Leak

Had the exact same symptoms on my 2004 Chrysler Grand Voyager CRD last winter. The loud hissing turned out to be a cracked vacuum hose connecting to the intake manifold. A leak detection test confirmed multiple vacuum leaks around the throttle body area. The increased fuel consumption happens because the engine management system tries to compensate for the false air readings. This causes the engine to run rich, wasting fuel and potentially damaging other components if left unfixed. The repair involved replacing two vacuum hoses, cleaning the throttle body, and installing a new air filter since dirt was getting past the compromised intake system. The job required removing several components to access the damaged hoses, but it was not a major mechanical issue. Important: Make sure they perform a proper leak detection test before replacing parts. The symptoms you describe are classic signs of vacuum leaks, but the exact location needs to be pinpointed. The check engine light likely shows a lean mixture code which helps confirm this diagnosis. No serious engine damage occurred in my case since I addressed it quickly. These vacuum leaks are common on this engine family as the hoses age and become brittle.

Thanks for sharing your experience with the vacuum hose issue. That really helps narrow down what I might be dealing with. Just wondering, do you remember roughly what the total repair cost was for the hoses, air filter and labor? Also curious if everything has been running smoothly since the fix or if you noticed any other issues with the turbocharger or intake manifold down the line? My check engine light started flashing again last week so want to make sure I catch any related problems early.

Went to the mechanic last month and got it all sorted. The air intake system leak was exactly what they found, a damaged vacuum hose near the intake manifold. Total cost came to 100€ for replacing the cracked hose and labor. Pretty reasonable considering the fuel economy issues it was causing. The check engine light went off right after the repair and fuel consumption returned to normal. No problems with the turbocharger or intake system since then. The engine runs much smoother now without that annoying hissing sound during acceleration. If your check engine light is flashing again, definitely get it checked soon. These cars are known for developing multiple vacuum leaks over time as the rubber hoses deteriorate. A proper leak detection test will show exactly where the problem is. Much cheaper to fix a simple hose than risk damage to other engine components. My advice would be to also have them inspect all the surrounding hoses while they are in there. Sometimes when one fails, others are close to breaking too.

Got back from the mechanic yesterday and can finally share what happened with my Voyager. They found two cracked vacuum hoses just like you described, plus the air filter was completely clogged. The engine misfire was happening because of all the false air readings. Total bill came to 220€, a bit more than yours since they had to replace multiple hoses and do a full intake manifold cleaning. At least the leak detection test helped them find everything wrong in one go. Car runs great now, no more hissing noise and fuel consumption is back to normal. Really glad I caught this before it caused more serious engine damage. The mechanic showed me the old brittle hoses and explained how common this issue is on these engines. Appreciate your detailed advice earlier. Helped me understand what I was dealing with and not get overcharged for unnecessary repairs.