Six problems related to engine exhaust system have been reported for the 2004 GMC Envoy. The most recently reported issues are listed below.
I have a 2004 Envoy xuv with a cracked exhaust manifold. My mechanic said he has seen a lot of these on the 4. 2 and tells me it is due to bad design. GMC won't fix it unless I give them about $1,000. 00. Exhaust manifolds almost never cracked in the past. Please insist they help us like we helped them.
2004 GMC Envoy 4. 2 liter engine - defective exhaust manifold. Noticed casting crack at 81,000 miles replaced complete manifold, 02 sensor, gaskets at 89,000 miles. According to dealer no recall or extended warranty on this part that many others have had crack.
I heard a clicking noise from under the hood and after pulling off the cover plate for the engine exhaust manifold I saw the manifold was cracked. At idle speed fumes get inside vehicle. Repair has not been made so old part is available. Upon research on the internet there are numerous other complaints of this problem. I sent an e-mail to gm and someone called and said they need more people to report it to get something done. I believe it is a safety issue because of the fumes and possible fire hazard.
Speedometer does not work accurately. Check engine light came on randomly. Is currently out and I was able to pass emissions, hopefully it will remain out. Had to replace many parts including the heater core, thermostat and coolant. Now I am experiencing a problem with the fan of the car.
Started to hear loud rattle coming from rear of vehicle, thought maybe a heat shield around muffler went bad. Took it into the shop and they stated "not sure what happened, though you have something that has come loose in the resonator". Around $100 to get the resonator removed, have not quoted a new one from the dealer yet. I would imagine the replacement part will fail just as the original part has done.
Investigated check engine light. Secondary air injection pump failure for emissions.