06 5.3 Loud tick Lifter?
 

Although this is a 67-72 forum I figured there are a lot of people very familiar with ls motors. I have a 06 Gmc Envoy Xl Denali with right at 150k miles. It has the 5.3 . I bought the car new and it has been maintained to a tee. Basically all recommended maintenance has been done since new. The engine ran like new until yesterday. I was sitting at a stop light and out of nowhere it developed a loud ticking almost similar to the sound of a exhaust leak but definitely coming from the engine. The truck also lost oil pressure. This is when I cut it off and got it towed. Now that it is home its got oil pressure but still has the loud ticking sound. After doing some research I see that many people have lifter issues which I am guessing is the case for me but I haven't taken off the valve covers to confirm. I would like to think I could replace the lifters and get more life out of this vehicle but the loss of oil pressure scares me. Any first hand experience or knowledge would be greatly appreciated.

Re: 06 5.3 Loud tick Lifter?
 

Unfortunately you have to remove the head to access the lifters on an LS. To lose oil pressure and regain it would lead me to believe you have a blockage somewhere.

Re: 06 5.3 Loud tick Lifter?
 

One question . Do you have Displacement on demand ( DOD ) . If so this is a common problem that happens . This happens like the flip of a switch .The intake lifter is of special nature and they collapse . When it does you can stick your finger between the push rod and the rocker arm so the lifter is just bouncing around in the bore which most likely the reason for you oil pressure drop .

The fix . You can either pull the heads and install new DOD lifters ( I recommend changing exhaust as well ) or do a DOD delete kit . This changes all lifters to reg ones ( eliminates DOD ) and a new valley cover . The delete is what most will do . I have an engine in the shop now that I will be doing it to . Do a google search DOD delete kit and you will see many offer it . Also read up on it if you plan on doing it yourself

If indeed this is your problem you can do this either way and drive that engine many more miles .

Re: 06 5.3 Loud tick Lifter?
 

The DOD system has an oil relief, so the momentary loss of oil pressure is a symptom of that. I'd doublecheck that you don't also have cracked exhaust studs on the rear 2 cylinders (very common for ticking noises). But the DOD system is the likely candidate.

Re: 06 5.3 Loud tick Lifter?
 

Mine is apart now for a lifter change. Its an 02 I just pulled the heads and nothing looks wrong but I have replaced with the new style ls7 lifters. I am putting it all back together. I hope it fixes the tick tick...

Re: 06 5.3 Loud tick Lifter?
 

ok just to bring this back up, I finished my lifter swap and it seems to have fixed my tapping issue. Mine is older and not DOD and I even understand the newer ones have the "better" lifters.
It is a chore since you remove the intake, exhaust and heads. I took a chance and only removed those and hoped it was not anything deeper. It sounded like lifter noise and it was, I will finish getting her together and drive to make sure.
Dave

Re: 06 5.3 Loud tick Lifter?
 

Along with what was mentioned, here are a few more common issues.
There is a screen under the oil pressure switch that clogs. The engine will still have oil pressure, but the sensor cannot read it.
Also, check the oil right after shutdown to see if it is aerated/frothy. Two things may cause this. First, at your miles/age, the oil pickup seal may have hardened and does not seal well. This allows oil pump to draw air past the seal. Secondly, there is an updated shield for the DOD relief valve in oil pan as GM found the oil spraying into sump aerates oil.
GM states to install this shield any time you do the lifters and have no history of it having been done.

Also, number 2 cam bearing is known to spin causing loss of oil pressure.

I would bet the loss of oil pressure is the screen under filter and noise at least one collapsed lifter. Small chance problem may be caused by the VLOM which controls oil flow to DOD lifters.

If replacing lifters, be sure to inspect cam lobes for damage/wear and valve train components for related failed cylinder.

Re: 06 5.3 Loud tick Lifter?
 

Might be a little late but if you're still working on it I'll give you my experience. My brother has a 2010 Yukon Danali with the 6.2 in it with DOD. My sister in law was driving it when it happened so I'm not sure if it had a drop in oil pressure but it developed a very loud tick as you're describing. We pulled the head on the passenger side of the motor and found two dead lifters. replaced and put back together. same noise. pulled the motor and dug deeper thinking the worst. Turned out that the cam had delaminated and a chunk was missing. replaced the cam and reassembled the motor. been fine since.

If you wanna check the cam, take a ratchet and spin the motor over by the crank. Ours had a catch that would stop the rotation. thats when we knew it was something serious. Might not be the same on yours but its something more to check if you're still hunting.

Re: 06 5.3 Loud tick Lifter?
 

Thanks for all the first hand info.I haven't had a chance to work on this yet but will post a update.