Replacement motor questions but hopefully fixable

[Rocket Man]

Show us a pic of the inside of your fuse box lid with the diagram.

Edit: you’ll have to ask the mods to move it. @NathanJax @07Burb @Shaggy @yates ™

 

[Fless]

Shoot, yep I posted in the wrong forum. Any way to move it?

@soulsea please.

 

[soulsea]

moved

 

[rockdogz]

Thanks for moving.
So just pull the connector on the FSCM while it’s running?

 

[Rocket Man]

Thanks for moving.
So just pull the connector on the FSCM while it’s running?

That’s what I did with my 08 Silverado.

 

[wsteele]

Compression checked out ok. Tried new plug wire and spark plug, and swapped coils with cylinder 2 - the misfire stayed on cylinder 4. I suppose it could still be a lifter right? The compression test wouldn't rule that out because it would fail collapsed right?

Yes, you could still have a collapsed AFM lifter (#4 is an AFM lifter). The sure way is to pull the valve cover and inspect the #4 rockers. If they are both straight and one is not loose, you probably don't have an AFM lifter issue. Turn the engine over and watch to see if the rockers on #4 are operating properly, if the are moving up and down in time, it isn't a collapsed lifter.

 

[89Suburban]

As far as the VLOM, I had already been experiencing some oil leaking from somewhere higher on the block and I was going to replace the valve cover gaskets. I also have some small amount of coolant leaking somewhere although I don’t see it on the ground. I just need to add more to the reservoir monthly when it gets low. When I read about the VLOM issues of oil/coolant leaking I have a feeling it could be related.

There is no coolant leak possible from the VLOM, only oil. However, there are 2 crossover steam pipes on the top of the cylinder heads that have little gaskets on them that do go bad and slowly seep, but not enough to smell or see a leak. Something to check if you go diving into things.

 

[V327839]

I swapped in a later 5.3 motor into my 04 Sub z71. I then had unexplained coolant and oil loss. Turns out the motor has the Castec heads that were prone to cracking. I had to replace them. I don’t remember having knocking or codes but I guess it could depends on how bad the cracks/leakage is. Wish I had a better experience to share.

 

[Tonyrodz]

I swapped in a later 5.3 motor into my 04 Sub z71. I then had unexplained coolant and oil loss. Turns out the motor has the Castec heads that were prone to cracking. I had to replace them. I don’t remember having knocking or codes but I guess it could depends on how bad the cracks/leakage is. Wish I had a better experience to share.

In my experience the 862 heads crack too.

 

[Fless]

Thanks for moving.
So just pull the connector on the FSCM while it’s running?

Run out of fuel yet?