Im starting to get sick and tired of dealing with my truck...

Here is the lastest thing to start going on. It has this pretty nast rattle on the FIRST COLD start of the day, and only when its REALLY cold. Like 45* and under. Just started about a week ago and this is the 3rd time ive heard it. Goes away once its warm and doesnt do it again untill the next first cold start of the day. Thought it was a cat, but checked after a short drive and they dont rattle. Could it be the flexplate? I also noticed a little bit of fresh oil from around the oil filter and bottom of the bell housing.

Cold start rattle - YouTube

 

I'd guess cat.

If it was the flexplate, it should stop if you put it in gear & put a light load against it. Also would not change with engine temp/warmup.

 

Well I banged on the cats after a drive and no rattle. It also seems to go up and down with RPM as i rev it a little in PARK. But it also goes away after it warms up for a few minutes.

Im totally stumped!

 

Hmmm , I know some early 5.3s had piston slap , but it's hard to tell from the vid , kinda sounds like valve train/ lifter not pumped up ?

High mile 5.3 right ? Might need new lifters if ya haven't done so.
You run 5w30?

A stethoscope would be helpful too .

 

I would agree, it sound like its valvetrain related.

My lifters in my 2000 don't pump up right away on a cold start either.

They also have a tendency to bleed down after running it hard and sitting at an idle.

I have ran all sorts of cleaning products through it and never been able to fix it completely. I just cann't see tearing it apart just to change the lifters since it has the dreaded piston slap as well. I am building a new motor for mine.

 

It was some what asked not yet answered. What weight oil are you using?

 

Lifters were replaced with new LS7s when the cam was swapped. It definitely sounded like it was coming from the bell housing area. Oil right now is just conventional 5w-30 but Im switching back to Amsoil full synthetic 10w-30 after my next tank of gas is gone.

 

Do you have an aftermarket stall in it?

 

Just for piece of mind double check your rocker arms. , I've had them come loose before , it's easy to double check .

Now you have new lifters I'm stumped .

Yeah if you did any work in the trans bellhousing area check that too .

 

No stall in it.

Nothing around that area should've been touched when the cam swap was done.

But I did notice a little bit of oil around the bottom of the bellhousing and oil pan where they meet. Could something with the rear main cause that noise?

I even put my hands on the manifold heat shields and they weren't loose. Is there any other heat shields in that area?