4.6 startup knock

[phiftybuick]

Hi everybody-
Just wondering if anyone has experienced a knock at start up. I have an '04 G/M with 45k on it, and it's been getting progressively louder. I use nothing but
Motorcraft 5w-20 and Motorcraft filters. It does it mostly when it's been sitting all night, but occasionally does it after only a few hours as well.
I LOVE my car! It gets 26+ MPG!
:(

Thanks...

[MENINBLK]

It sounds like the drain back valve in your oil filter isn't working properly.

Did you buy a CASE of filters ?
You may have gotten part of a run that has bad valves in them.

My Marauder will rap on a startup only after it has sat for at least a week.

[michael ward]

my marauder does it almost everytime I start it for the first time of the day.. with amsoil filters or motorcraft filters..

[Bradley G]

Welcome !
Marauder with 3k miles on a remanufactured motor, raps on cold starts only.
Marquis with almost 60K, no rap on hot or cold starts.

[SergntMac]

Had it on my '91 GM with the 5.0L pushrod. Every first cold start of the day, like clock work. Sounded like a typical rod knock for about 15 seconds, then gone until the next cold start. No other symptoms, or, problems.

I will be cold starting both MMs later today and will give everything a second careful listen, but I haven't heard anything yet.

[MM2004]

Hi everybody-
Just wondering if anyone has experienced a knock at start up. I have an '04 G/M with 45k on it, and it's been getting progressively louder. I use nothing but
Motorcraft 5w-20 and Motorcraft filters. It does it mostly when it's been sitting all night, but occasionally does it after only a few hours as well.
I LOVE my car! It gets 26+ MPG!
:(
Thanks...



A knock often refers to bottom end.

A tick, more times than not is valvetrain.

Are you sure it is a knock and not a tick?

Mike.

[phiftybuick]

Yes, it's a lower-end knock. It doesn't last long - - maybe 2 seconds, but enough to bug me. From what you all are saying, it sounds fairly normal.
I'll keep listening to see if it gets any worse.
Thanks a lot y'all!

[JACook]

Mine does in on the first startup of the day. Definitely sounds like a rod knock. Lasts no more than a half second.
I always use Motorcraft filters, and Motorcraft 5W-20. I also prelube my filters when I change 'em.

I bought the car with 16K miles, and it now has 42K. There's been no change in the severity or duration of the knock,
so I'm not really concerned about the bottom end. I would like to see the engine speed flare less at startup though.

[Marauderjack]

Someone here said it was not rod knock but timing chain banging around until the tesioners build pressure??:confused:

I know it was a noise associated with most Mark VIII's and I never heard of a failure related to it!!:beer:

I believe out engines are set up so tight that it cannot be rods knocking!!:bows:

My $0.02!!:D

Marauderjack:burnout:

[DEFYANT]

Rod knock.

The 04 CVPI with about 45K miles does it too.

[JACook]

Someone here said it was not rod knock but timing chain banging around until the tesioners build pressure??

Well, all's I can say is, I've rattled a few rods in my day, and that startup noise sounds just like it.
A rod knock is a pretty distinctive noise, so if it is the tensioners, it's got me fooled.

[Marauderjack]

"Piston Slap" in GM cars sounds like rod knocking!!:cool:

Whatever it is it doesn't seem to hurt anything!!:beer:

Marauderjack:rasta: