Pending confirmation, it is not a secret. I just do not want to share something that does not work.

 

It is being 5k+ miles since I put Mobil 1 0w20 high mileage extended oil in the engine. Originally, the engine got more cold start clutter until about 3k miles. Then the cold start became much easier (even with temperate below 0F) than before and the notorious rattle, I had before, went away. I have heard only a few times ever since. Before I had a joy to hear it everyday. It is definitely does not fix all cold start issues but it worked for me. I added less than 0.5 quart of oil during 5k+ miles. I took 2 extended trips over 500 miles each + I commute daily around 40 miles on highway. The car sleeps outside. I hope, it could be helpful to some.

 

Good to know but the source of that rattle is disturbing. I would lean toward VVTI actuators on the exhaust side not locking or the non-ratcheting chain tensioners bleeding down. The anti-drainback valve might also be an issue? That's one thing I dislike about canister filter cars, you can't just throw a suspected bad ADBV filter away and put a new one on.

Strikes me as strange since I have left my 460 sitting for a week plus and it's silent on start.

 

What actually rattles, I do not know. I go by what people with more experience tell me. I did not want replace any parts yet as when the car gets warm, the engine has no suspicious noises. The engine has 174k+ miles on it.

 

An update to old thread, I got my morning rattle resolved by using oil and fuel additive: MMO regular for fuel and MMO Synthetic for oil. Before the rattle would happen even when it is low 60s. The temperature recently dipped to lower 20s and no rattle. The solution is not going to work for everybody but it worked for me. Please, do not start discussion which additive is better or if it works at all...

 

what year and mileage?

 

2010 AWD 185k+.

 

Did your car have the valve spring recall performed? And does it burn any oil between changes?

 

No, my car engine did not have problems with spring valves. The issue has impacted, as far as I am aware, earlier years and RWD trim only. It only takes some oil under heavy load in mountains but not on flat lands.

 

so low oil can be ruled out. I’m left with vvti or possibly a timing chain tensioner. But in any event the problem seems to be resolved for now. If it occurs again I would consider investigating those two things.

 

I check oil often just as a precaution. The rattling got worse when I switched from Toyota oil to Mobil 1 0w20. But it got better when I switched to Mobil 1 0w20 high mileage extended performance. But the rattle would happen here and there during cold start but not nearly as often. With MMO, there is no rattle. I don't really care about additives, however, I used MMO in the past and it worked.
Recently, I had to do a tuneup on my track and used B12 to clean combustion chambers (it needed it), LM engine flush and MMO in fuel and engine. I was happy with results. However, I was afraid to use B12 and LM engine flush on LS460 so I used MMO only because the way it deals with dirt. It is so far so go.

 

if you had to guess what could be the underlying reason that caused the rattle to develop what would you say is? Just curious.