'07 Yukon XL Denali motor tick when 1st startup

[BSarteSr]

Active Fuel Management, also known as DOD/Displacement On Demand. It turns 4 cylinders off under certain conditions to "save fuel". It works by collapsing the lifter to keep the valves from opening on those cylinders.

I have heard/read that the 6.2L suffer from piston slap on start up. I don't own a 6.2L so I can't say what it sounds like compared to a lifter tick.

Just out of curiosity, are you using oil filters with a good anti drain back valve?

Does it make the noise every time you start it or mainly after sitting overnight?

Thanks for the info! The AFM is something I definitely would not want, in concept sounds good but probably a lot like some of the other ideas these auto engineering geniuses came up with back in the late '70's and '80's!

I use AC Delco filters.

The ticking sound is not there unless the engine has had plenty of time to cool down, at least several hours but not as bad as when it sits overnight.

 

[Raptor Tahoe]

Thanks for the info! The AFM is something I definitely would not want, in concept sounds good but probably a lot like some of the other ideas these auto engineering geniuses came up with back in the late '70's and '80's!

I use AC Delco filters.

The ticking sound is not there unless the engine has had plenty of time to cool down, at least several hours but not as bad as when it sits overnight.

Looking forward to hearing what you find out. My 07 Tahoe LTZ makes the same noise on cold starts and stops after a minute or two. Good luck!

 

[wjburken]

Thanks for the info! The AFM is something I definitely would not want, in concept sounds good but probably a lot like some of the other ideas these auto engineering geniuses came up with back in the late '70's and '80's!

I use AC Delco filters.

The ticking sound is not there unless the engine has had plenty of time to cool down, at least several hours but not as bad as when it sits overnight.

My guess is piston slap or exhaust manifold leak.

Broken or loose manifold bolts are fairly common. When cold, the manifold can leak and then as it heats up and expands, it seals up.

Wouldn’t hurt to inspect your valve seals and springs, just to be sure.

 

[mikeyss]

Btw, How’s that coming along mikey

Found a new LS3 block, doing a forged TSP crank, Mahley 4.07 pistons, TSP heads, and it's all going to get balanced. That's on top of the TSP VVT-1 cam and ARH Long tubes. This got expensive quick

 

[Fless]

My guess is piston slap or exhaust manifold leak.

Broken or loose manifold bolts are fairly common. When cold, the manifold can leak and then as it heats up and expands, it seals up.

x2 on the loose exhaust manifold bolts, if they're all there.

 

[Geotrash]

I have an 09 6.2 that had the noise you describe and thought it was a lifter. I found out too late that the valve seal can fall out of the head. I pulled the heads and found the lifters were fine, it was the valve seal making the tick noise until it warmed up, it would sort of seat itself as it warmed up. But the last time I started it, the valve seal fell out and destroyed a piston. It was running perfectly before it happened, and the next time I started it...ka boom!

Mike, I had no idea there were other members here from Longmont. My wife and I have a house there in west old town, and used to be there twice a month. We've been driving back and forth to Richmond occasionally since COVID started, but plan to be back there more often next year. Send me a PM if you want to exchange digits and I'll look you up next time we're back there.

 

[BSarteSr]

My guess is piston slap or exhaust manifold leak.

Broken or loose manifold bolts are fairly common. When cold, the manifold can leak and then as it heats up and expands, it seals up.

Wouldn’t hurt to inspect your valve seals and springs, just to be sure.

Trust me, this is not manifold bolts! Built too many motors to be able to tell!

 

[wjburken]

Trust me, this is not manifold bolts! Built too many motors to be able to tell!

Understand you have a lot of experience, but I would still check them just to confirm since it’s an easy check and a very common issue on these motors. As I say in my signature, Ask the stupid question so you don’t have to fix a stupid mistake.

 

[avalonandl]

x2 on the loose exhaust manifold bolts, if they're all there.

LS engine tick on start up is very typical. Mine does it....

 

[SUMTOY2]

I have had my '07 Yukon XL Denali since 2008, bought it from dealer with 12k miles, they said it was a lease that was turned in.

Pretty much from the very beginning there was a very small ticking sound when it was first started. I am very aware of all the noises my cars make (done many frame off restorations, rebuilt MANY SBC/BBC/Buick motors) and this tick always sounding like a lifter, but not serious since it went away after a minute or so when the engine warmed up.

Recently (in the past month or so) it has gotten more pronounced when I first start it up and lasts a little longer, usually until it is warmed up, then seems to run fine.

I have changed the oil every 5k miles, filter every other oil change, use good brand of synthetic oil, use 5/30 in winter and 10/30 in summer.

Last time I changed the oil I added some STP oil treatment (I am old school and that has always been good for the lifters, especially in my BBC's). Seemed to do some good, ticking was not as pronounced nor lasted as long until yesterday. Weather has gotten a bit more chilly, but my truck is ALWAYS been kept in a climate controlled garage.

My question is about replacing the lifters in these LS motors? From the engine work I have done, very aware of the ins/outs of just replacing lifters versus a new cam/lifters/head work and what it would probably take to do all of that since I have done any work on these newer LS motors.

Are there any other additives that I can try (about to change the oil in the next week or so)?

BTW, the engine has 158k miles on it and like I said, oil changed every 5k miles!