Ticking noise in engine

**hkinsland** · 11-15-2009, 10:58 AM

My wife's 2004 Tahoe has developed a ticking noise in the engine that only occurs between 1500 and 2000 rpms. I put it in neutral with the emergency brake on and ran it up to that range and it still occurs so I popped the hood, had her run up the rpms and it seems to be coming from the top of the engine on the drivers side. It is a metallic ticking noise almost like an old sewing machine. Any ideas as to what this is? The engine has 104k miles on it.

**tbplus10** · 11-15-2009, 11:19 AM

Possibly lifters, try an oil additive right before the next oil change to clean things up.
I usually use Marvel Mystery Oil to clean sticky lifters.

Injectors have been known to give off this sound too. Again an additive in the fuel may help there also.

Try using a mechanics stethescope to beter isolate the noise.

**Kenny** · 11-17-2009, 04:56 PM

mine just started doing this, but only when i accelerate, trying to isolate cause..ideas?

**Chris Miller** · 11-18-2009, 05:29 PM

Lifters. If you've got more than 100K miles, it's to be expected. Kenny, do you have a 350?

**Chevyboy96** · 11-18-2009, 06:23 PM

Yup sounds like lifters

**Kenny** · 11-21-2009, 11:40 AM

Originally Posted by Chris Miller

Lifters. If you've got more than 100K miles, it's to be expected. Kenny, do you have a 350?

its a 3.5L...did a obd2 scan...lean condition on both banks as well as 02 sensor 2 low input, and tranny range sensor.

codes were P0171, P0174, P0332, P0705

doesnt do it when idle in park when i rev or when cruising, only when slightly giving gas between 1000 to 1500 rpm's.

**Chris Miller** · 11-22-2009, 02:00 PM

If you're running lean, that's probably causing your ticking noises, then. Change that O2 sensor first, because that can give a bad reading and make the PCM cut down on fuel.

**b_burdine** · 11-22-2009, 02:05 PM

it's just piston slap... not too much to worry about unless it gets worse

**Kenny** · 11-23-2009, 04:49 PM

solved it...it was actually the freakin pvc valve. guts were gone. installed a new one and good. guess the guts are now bouncing around in one of the cylinders....

**tbplus10** · 11-23-2009, 07:52 PM

Originally Posted by Kenny

solved it...it was actually the freakin pvc valve. guts were gone. installed a new one and good. guess the guts are now bouncing around in one of the cylinders....

For your engines sake I hope not. This could lead to some problems.