Can someone who works at a GM dealership tell me if installing aftermarket guages such as EGT does anything to the warranty. I emailed GM, but was advised to be safe not to do it, and besides the computer would not let the EGTs to get to hot----is this true?

Suggest you contact SpeedPro1... or dig into this thread: http://www.dieselplace.com/forum/showthread.php?t=244397

GM can pretty much do whatever they please... and SpeedPro1 found that even though he had an EGT gauge, GM assumed he had a tuner in place when an injector failed and toasted the engine. He fought it as far as he could go and they never agreed to warrant the engine.

The ultimate answer to your question falls on the individual shop and the regional service rep. If you're luck, you'll be OK. If you're not, you're screwed.

Moved to Warranty Issues & Recalls. That may also help.

Can someone who works at a GM dealership tell me if installing aftermarket guages such as EGT does anything to the warranty. I emailed GM, but was advised to be safe not to do it, and besides the computer would not let the EGTs to get to hot----is this true?
Depends on the stealer. The one here in town says yes, they will void the warranty if they see it. The one 25 miles away said if there is an an issue and a GM Field rep wants to look at it he will call me and have me authorize them to replace the exhaust manifold and remove the gauge before the Field Rep looks at it.

What happened to the law that stated any mod was legal but if the mod caused the failure it was then that it was not warrentied. I have dealt with these issues on other boards on off road vehicles. I have been out of that loop now for some time but I am curious. Check with SAN the Sema Action Network.

I could understand not warrantying the work if they found metal shavings in the turbo or similar.

get this.......the new FERDS come with a boost gauge then they might put an egt gauge in the 2012 models you would think any truck that does a lot of towing should come with an EGT & BOOST gauge from the factory.........spissst GM.... FERD is gonna beatcha too it):h):h

get this.......the new FERDS come with a boost gauge then they might put an egt gauge in the 2012 models you would think any truck that does a lot of towing should come with an EGT & BOOST gauge from the factory.........spissst GM.... FERD is gonna beatcha too it):h):h

Well you would think with the big HP race with the diesels EGT and boost gauges would be part of the gauge package. At leas the option of them would have been a bonus.

I have both on my 03. Only thing drivetrain not stock is the exhaust.
For the computer keeping EGT's down, I don't believe it. Granted mine is an LB7 but I have hit 1300 with no trailer. Did have to stomp on it and hit about 80 going uphill, but at what point will the computer back off the truck to cool it down? Never heard of anything like that before.
Anyway, I would agree depends on the dealer.
I will also add that I have seen the same thing about it should still be warrantied so long as the aftermarket or modified parts did not cause the damage. Like changing the lights to led lights and having the injectors go. Completely unrelated. (I know alittle out there, but get's the point across.)
Just depends on the dealer, if you find a bad on and you fight them, not saying you won't win, but it's not going to be easy.

GM HAS to provide proof that your guages, that do nothing more than relay a temperature or boost reading, caused an engine failure. If they take a snap shot of your ECM and see nothing...they HAVE to warranty your engine or transmission. This would be a pretty simple argument in a court of law. New protocall for GM is that dealers must take a snapshot of the ECM before major engine work to determine if a "power up device" was on the vechicle at one time. Also, if you are an Onstar subscriber, and subscribe to their montly email diagnostics, it will tell if any devices have been hooked up...you can use that as proof. Guages are not a power up device, and no where in the owners manual does it say you cant add them. I agree that many dealers and GM reps may try to fight you on it, but in the end, they cant live by a double standard...the burden of proof is on them.