jsm

Bought Yukon XL 5.3 flex 4x4 with 21000 km. Put Mobil 1 in at 23000km, started getting lifter noise at startup overnight. Lasted a little longer each day. Changed oil and filter back to dealer 5w30 at 24000 km, no more lifter noise at startup. Maybe this is answer for others with this problem. Don't use synthetic oil ?

73shark

Hard to say since we don't know what its past maintenance history was. I suspect if it was really a lifter, then as the fresh oil gets a few miles on it, the noise will return. Oil changes rarely fix mechanical problems.

guvner

I have a question here... Does the synthetic have more detergent? Does going back to the old oil type thicken it back up again possibly causing the lifters to seal a bit better? Often wondered what the actual differences are in viscosity
at the startup temperature versus the operating temperature..

Guvner..

jsm

Synthetic oil has better flow characteristics when cold as well as hot than conventional oil. If it can flow in better, then it can flow out better as well. I think that this is why engines with cylinder deactivation have this lifter noise at startup. The mechanism that allows this function also allows oil to drain down overnight, or several hours. When I test drove my Yukon XL, it was 10 degrees F. outside. When I picked it up it was the same outside temp., and heard no lifter noise at start-up. Everything was fine for first 3 weeks until I decided to treat my engine to Mobil 1, then a day or two later I thought I was hearing things in the mornning at startup. Sure enough, my almost new engine was sounding like an old clapped-out GM when started after a few hours, clack,clack,clack,clack, for a second or two. The duration of this clacking, got longer each day, until it was maybe 3 or 4 seconds each morning. This was driving me crazy. I was standing outside the vehicle at each start just to confirm what I was hearing. Then it hit me. Maybe it was the synthetic oil draining down. Went to dealer and told them to change oil and filter again , it's my money, humour me. Next day, no lifter noise. Just spent 2 days up north on Georgian Bay. Started after 2 days sitting. Guess what? No noise. What would any reasonable person conclude from this ? Me too. My caddy has been running fine for the last year on Mobil 1, so did my 03 Venture, but the 5.3 in my Yukon can't stomach it. I've read all the posts on this and another site about this lifter noise, and can't believe that I'm the only person to think of this cause. I was hoping that guy with all the GM answers would see this, as he seems to know his stuff. (zx1100 ?). I worked fixing cars back in the 1970's to 1980's, and I think I know what lifter noise is, but I'm willing to listen to something else as an explanation. I've always thought that sound can't be good for the engine over the long term. Both Mobil 1 and Amsoil web sites have excellent info on synthetic oils by the way. That's how I decided to use it. Also if synthetic is good for new caddies and corvettes from the factory, then it must be good for my Yukon XL right? Wrong. Shop foreman at my Pontiac GMC dealer says if owner's manual doesn't say to use synthetic oil then don't use it. Maybe in this case he is right.

ZX1100F1

If the lifter tick noise lasts longer than 1 minute after the 5.3L (with AFM) has sat 4 hours or longer (cold soaked) then it is likely you have a faulty lifter, the corrective course of action is to replace the entire set of lifters.

While synthetic oil is not the cause of this problem its flow property's can make lifter ticking sound worse then conventional oils.

Have your dealer reference GM Document ID # 2065710 for instructions to remedy this.

Dave

jsm

Thanks zx, was hoping to catch your attention. Confirms my suspicions about synthetic. Talked to a caddie salesman today, he says 6.2 is quieter in escalade than 5.3 in yukon. I guess this would apply to Yukon Denali with 6.2 as well. What do you think?

73shark

I believe the 6.2s are sans AFM.

ZX1100F1

No question that the L92 Cadillac 6.2L is quite and smooth mostly the result of VVT, although the exhaust note is a tad bit more aggressive then it's smaller Gen IV cousins.

Shark's right, The L92 does not have AFM.
Variable Valve Timing and Active Fuel Management are difficult to integrate into a single engine although on the new 6.0L Hybrid you now see AFM and a derivative of VVT which is called LIVC (Late Intake Valve Closing), we will see more of these technologies hitting the market in upcoming models.

jsm

You guys are a wealth of info. Thanks. Your right. No AFM on 6.2. Have been studying GM website, and have noticed that Yukon Denali has acoustical insulation whrer the lesser models do not. Perhaps this is why my caddy saleman is convinced that my Yukon has has more engine noise than an Escalade.

J2THEB

I get what sounds like lifter noise all the time at idle. I had my oil changed and it's no different. Anyone else having this problem?