Engine Tick Diagnosis

sicsiksix · January 20, 2008

Just trying to get some more ideas on what is causing my engine tick. I just bought this truck a few weeks back, 2002 GMC Sierra 2500HD 6.0L 4x4 with 56500km on it. Now I didn't notice the noise the day a bought it, then over the next few days it became more apparent. I do have some piston slap in the mornings, but from what I can tell it goes away after a couple minutes of driving. This noise can be heard quite a bit more clearly from the sides of the vehicle rather than over the top of the engine. Its very noticeable at idle and when I snap the throttle under the hood, the noise can only be heard on deceleration. It doesn't go away when the engine is warm either. I tried running some seafoam through the pcv, that didn't do anything. I changed out my oil and filter yesterday and replaced with Pennzoil Platinum Synthetic 5w30. I tried unplugging each coil one at a time and the sound didn't go away, unplugging any of the coils made the engine run a little rougher. I've also noticed a slight stumble at idle when the engine is warmed up. I replaced the PCV, fuel filter, fan belt, air filter, cabin air filters, front/rear differential fluid (royal purple 75w90+white vent plug), transmission/transfer case fluid (royal purple max atf). Im not sure what I should do. I bought the truck from a dealer and have another 3000km worth of warranty on it. Any suggestions? BTW I have a spare 6.0L long block that has been freshly bored/balanced/etc which could go in i suppose, rather fix the one in there though and save the new one for when this one dies.

Rudy35 · January 21, 2008

Could it be an exhaust leak? Check for broken exhaust manifold or studs.

sicsiksix · January 21, 2008

I don't think its a exhaust leak, I had a exhaust leak with my 89 305 and the noise became more pronounced under load. This problem doesn't not get any worse with load. It becomes harder to hear until I let off the gas. It sounds very loud when I'm in a drive through or near a building. But I will check for an exhaust leak tomorrow morning when I start it up. It is supposed to be about -10 celcius so if there is a leak that'd be the time I would be able to spot it.

eldirector · January 22, 2008

Sounds like you are describing the same "tick" I hear on mine ('03 1500HD). I believe it is the injectors. Two dealer service centers claimed it was "normal", and I haven't had issues other than the sound, so I've let it go. 70K+ miles, and still ticking away...

sonjaab · January 22, 2008

Injector poppets doing their thing is correct! This noise drove me crazy

on my 01 and 04 6.0s. Dealer said normal. Checked myself with a borrowed

engine stethoscope and sure enough!

My 07 6.0 is the same!............geo

sicsiksix · January 22, 2008

I sure hope its the injectors. I actually held a long screwdriver to the fuel rail a few days back and the tick did sound very similar to what i heard. Cant tell for sure without a stethoscope, it's on the top of my 'To Buy' tools at the moment. I am also planning on doing an injector cleaning in the next couple days, and change out my plugs/wires after the cleaning. Hopefully the noise will atleast calm down some. I'll report back as to what happens. Thanks for all the input guys, I really appreciate it, always nice to get some other opinions.

sonjaab · January 23, 2008

Don't waste your $$$$$$$$ on "snake oil" and un-needed parts!

The "tick" won't go away !!!!!!!!!

Auto stores and Harbor Freight/tools sell a cheapie stethoscope for

less than $10 bucks..............

sicsiksix · January 23, 2008

Thanks for the advice, I think I am going to purchase a higher quality stethoscope though, The last cheapo one I bought (powerfist crap) didnt last more than a year or so. As for the parts, they are all just my tuneup parts. I always replace as many things as I can when I first get a vehicle to ensure proper performance and longevity. Apprently the fuel filter and air filter was changed just before I got it, but the air filter was black and I could barely blow through the fuel filter. Better to check 'em all now while it still moves before it leaves my stranded.