I have a 2001 duramax , yesterday suddenly the engine got really loud. It was like you fliped a switch. looked at the gauges and the temp was low around 165 or so. Took it to the local dealer in Mobile Al. said it was the themostats. Had the stats replaced today, temp is normal at 205 but, high idle and noise is still there. Could it be that the tech didn't reset the codes and this is causing the problem. Ran it 500 miles Sunday and was ok. Filled up that night, drove about 60 mile the next morning when the problem started. a

Also had fuel filter change about 2000 mi. and oil 2500 miles ago, have a six speed stick shift in the truck.

i think i have an idea about whats going on

do you have a check engine light on? are you idling around 800rpms in gear? do the injectors sound funny like they are over fueling or something along those lines?

my truck has bad injectors, so every once and a while it will set a p0093a and a p0093b, when i see both those codes, the truck will idle high and run funny as balls, all i do is clear it out and go about my business, i don't know if your having the same issue, but my gut guess would be clear your codes and your truck will be fine

Your dealer didn't clear the computer. I had the same thing happen to me this past winter. Thermostat stuck open, when the engine doesn't come up to temp in a certain time it sets some code... but no light on the dash. It turns off the pilot injection so it sounds pretty loud like a 12v cummins. Get your dealer to reset the computer and all will be well most likely. I can't remember the code number though.

Thanks for the info. I took it back to the dealership today, They reprogrammed the computer and everything is ok. I had all injectors changed 3 mo. ago. But to tell the truth this truck cost me around 8k in 09 and about 1k this year allready. new clutch,fw,pressure plate and ect, transfer case, new injectors, idler pulleys, belt tens., and on and on. I am thinking of getting rid of it. GMC 4 door, long bed 4x4,6 stick, color red, cow killer bumper.190k on truck. new tires and all fluids just changed. oil is changed every 3k miles. any taker???

Seems like you just had bad luck and got a beaten on truck. I've got 160K miles on mine its an 01 and have only had to do normal maintenance so far. Did the rear brakes last year, need to do the fronts now. Put new idler pulleys on last month and thats about it. You gotta think a lot of people don't take care of the vehicle, and then they get high mileage on them so almost everything starts wearing out at the same time.

if your giving it away sure ill take if off your hands lol i could use a fuel mileage truck and wow 6speeds are schweet

i thought you where having a different issue, thermostat stuck open causing all those issues is funky, wierd trucks

my truck has 182k on it, and its had some issues, but it could be worse, always remember that

I would like to chime in on this post. I have an '02 with 230k miles and the only engine work has been GM changing the injectors at 180k (free to me), new starter solenoid (original one was struck by road debris and broke it) and recently changed the water pump and both thermostats. I put in a SBC single mass flywheel and single ceramic clutch. Besides that, everything else has been either upgrades or general maintenance. The truck is still running the factory brakes. I probably have 30k plus miles pulling my 5er.

MaxRock