I run liqui Molly optimal synth 5w40. No oil usage no noise.

 

Sounds like my '11 that's been doing it on cold starts periodically since I bought it in '13. Had Lexus look at it and they found no problem. IMO, forget about it.

 

0w is always better than a 5w since it will flow faster on startup, the first number doesn't mean it's thin at all it only tells you the cold flow rate. The 2nd number is the operating temp viscosity and is the one that matters, a 40 weight is not ideal for these engines

 

It sounds like a bad belt, tensioner, or pulley bearing. I would try removing the belt and doing a cold start. If the noise disappears, it's in the accessory drive system.

 

My 2017 makes about the same sorts of noise when started cold and chances are it is nothing to worry about. My 2002 Camry V6 has a slight noise that sounds to me like a connecting rod big end bearing, and I worried about that noise for the longest time. Even though the noise goes away in a few seconds, and I'm pretty sure what causes it (i.e. a simple matter of cold engine start-ups), I have tried any number of oils and additives to attempt to eliminate that little tick tick after starting. Some, like Slick 50 and Marvel, seem to work for a little while, at first, but the noise always comes back. But since the noise hasn't changed over the years, and the big kind of worry that gives people fits - that it'll get worse one day - has failed to materialize after 200,000 miles.
So I'm not saying to just ignore an engine noise necessarily, just to be mindful if the noise ever changes. And keep your oil level up, but don't worry about it needlessly. Because chances are this noise is normal for this engine and it's unlikely it'll ever harm a thing. The noise to beware of is the noise that doesn't go away once the engine is warmed up!

At my last oil change I tried some of this stuff, from Lucas for $14. It did cause some improvement to quiet those minor noises after a cold start. Other than that, I just change the oil every 3 months and forget about minor engine noises. Without belaboring the obvious, the engine is designed to run its whole life cycle hot not cold - so for that reason, all the clearances on all automotive engines are inevitably slightly looser, by design, just to compensate for that. A car engine takes a while to get to the temperature it is designed to run at and that's why it's called "operating temperature".

 

Don't wait until your next service in a few thousands miles. Take it to the shop. Probably wouldn't hurt to drop the oil pan and check for any debris. Mechanic can tell a lot based on what kind of debris he finds in the oil. Check for the rod bearings and such. Also sounds like something in the valvetrain. You saying it has full service history. Was it serviced with 10K miles oil change intervals? My dealer wanted me to do 10K oil changes because it is free, I told him to take a hike, I'm doing 5K. LOL.

 

After adding two bottles of completed fuel system cleaner, the problem was solved. It starts much easier and normally than before.

 

Mine does the same thing on cold starts. Been doing it since I got it 25k miles ago. From the research I did, it might have something to do with the VVT-i system and oil not staying in the system, so what you're hearing is a dry start until the oil makes it into all the nooks and crannies. I use high quality 5w-20 synthetic oil and that's it. I've run the car hard too and have not had any issues and the noise hasn't gotten any better or worse. If you take it somewhere, they're likely to give you worst case and talk to you about full engine rebuild. Monitor it. If it gets worse, take it somewhere.

 

sounds like a flat hydraulic lifter to me. It goes away when warm because the oil flows into the tapet easier. When it's warmed up. And the gunk inside get warmed up and lets the internal workings of the lifter free.

take the engine covers off. Get a stethoscope, and listen along the top of the valve covers. I bet you can find wich one it is. Then decide on if you feel like pulling the cam or not.

You could also change the oild get the engine up to operating temp, shut it off : and put a 1.5 quarts of diesel in the oil. Then let it idle for 5-10 mins. Shut it off for 10, and idle for ten for a few cycles. Then let it sit over night then do one more heat cylce. It will break down any gunk in the lifter and it may purge or clean the spring and bearing style valves the lifters have inside them.
then drain the oil and refill it. And spin a new filter on. The diesel won't hurt a thing . The seals and gasket metals and sensors will all be fine.

this technique works really well on hydraulic lifters.

most the time they get gummed up inside. And the little popit valves in the lifters just get all stuck or sticky. If this don't work I would be contemplating changing the lifters , when they get flat like that. It's hard on the surface of the cam. And will take the hardening off the lobe surface and the face of the lifter once it get bad enough for long enough.

Also you could dump a quart bottle of stiction eliminator in the oil instead of using diesel and just drive it as well. The hot shot pro for the diesel injectors works amazing . It's expensive but it is designed to go Into your oil. That stuff is proven it works. And it dosnt have a very strong scent either.

 

I was never able to replicate that sound for the dealer or indy shop for my 2009 LS. I purchased my LS in 2019 with 120k miles and made that loud tapping sound for a few seconds on a cold start, which in my amazement it's a rare occurrence for this cold start tap. Sometimes it makes that loud cold tap sound and sometimes it doesn't. I firmly believe it's the timing chain tensioner! I took it to my indy shop in brentwood TN and they wanted to replace the whole motor instead of doing my request of a whole new OEM timing chain and new tensioners. Since the car had 295k miles at that time, It now has 303k miles. If I'm ever going to get a new motor in my LS it's not going to be 4.6 1UR-FSE, it's going to be the new 5.0 liter out of the IS500. After the indy shop told me they want to replace the motor instead, I bought a 16 Audi TDI and no problems and gets better mileage. 09 LS my current MPG average is 27-28mpg. 16 A7 TDI gets average 36-38 MPG. Both of these averages are real numbers I computed at each fill up for each vehicle. Reminder I daily drive 200 miles a day. I live 100 miles away from work.... Damn I'm bad about getting off topic.

Back on topic, this timing chain cold tap is perfectly normal and will not ruin your motor. Since I've had a concern over this tap for years but kept on daily driving the LS for 183k more miles and still runs perfectly like it should.

 

Tune your 3.0TDI with Malone tuning, he will make it so you hit over 50mpg and be as fast as the LS was. It will also reduce your risk of EGR clogging and DPF failure

 

So, it was injector noise?

 

Yes i hear mine when its very very cold outside and i'm pretty sure its the bearing or the tensioner.

 

I know this is an old thread and I'd posted something about this recently, but this is the sound I was talking about on my 14 with 94k. I think it did it about 4-5 times, but I haven't really heard it since. From my post, I was told it was nothing to worry about. I'd posted a video on one of the FB groups and they told me to replace the timing chain tensioners as if the sky was falling and my engine was about to go; others told me it's not an emergency but to get them replaced at some point. I put 500 miles a month on the car, so I'm not going to worry about it. The car had great service records and started out having the oil changed even before it was due; then it went 4 or so oil changes at about 7500 miles, which concerned me. It was only serviced at Lexus before I had it according to the records consistency, but the PO could've had a couple of oil changes done elsewhere. Wouldn't be able to prove that if they did. I change it every 6 months since I don't put 5k on it within that time. Oil is clean and car runs great. I've attached the file of the service records I input into Excel (from My Lexus and what I've done since I've had it). I'm chalking it up as being the nature of the beast, especially since it's a rare occurrence.

 

Check oil level and smell for burnt or gasoline. If its needed. Buy two motor flushes and run as directed and change.

Make sure you're using the right oil on the cam that starts with 0w.

And always use 93 octain.