While fixing my FPR issue, to I took the opportunity to change the lower intake manifold gaskets. While I had the manifold off, I noticed between the block and the lifters/rods for #4 there was a decent amount of sludge, localized to pretty much right behind those pushrods. Everywhere else in the lifter valley was pretty much clean. This cylinder running a bit hot perhaps? Plug and gap looked ok.

The engine's got 95K miles, been running Mobil 1 since I bought it at 45K in 2002. Being the first time I've had the manifold off, I can't say how long it's been happening. It wasn't a terrible lot, but enough to make perhaps a golf ball sized glob of it when it was all cleaned out.

Suggestions?

 

Penzoil, the sludge maker. I rebuilt the top end of my motor back in the 70's, and seen first hand what using Penzoil did to my valve train. Oils have come a long way since then, but in my opinion, sludge is built up from condensation and old oil. Old oil meaning, not changing it every 3-4000 miles, and not running the motor up to operating temperatures in ed., short trips.

 

Marvel Mystery Oil will clean it and keep it clean.
Follow the directions on the container label.

 

A good while ago someone posted a picture of what you appear to be describing. It was due to a compromised head gasket.

RBob.

 

When I took the intake off my truck to clean the EGR ports, little pieces of carbon were laying around underneath. When I picked them up, they just fell apart in my hand. I'm assuming this happens when oil gets a little too hot.

 

There's a difference between sludge and carbon. Sludge is oil that has broken down with any detergents gone and forms a thick goo. Carbon is burnt gas and oil, (exhaust) especially in the EGR where that's what is circulated to reburn in the combustion chamber. You shouldn't of had carbon in the lifter valley. Maybe some fell in when you removed the intake?

 

Here is a pic of the clogged port, and a pic of the whatever. There were 3 of them. Whatever it was, it was not gooey at all. It was like holding a handful of little rocks slightly glued together. I just assumed they were big globs of carbon.

 

That is carbon for sure. I'd say the EGR caused the sludge to cook on the head. That's one reason i hate EGR's. They just gunk up the whole intake and cut down on performance, not to mention making your whole top end heat soaked hotter. I replaced the upper and lower intake gaskets on my girls 2004 Impala a few years ago. I literally had to soak the intake over night in parts cleaner to clean it up. What a gooey carboned mess.

 

On the truck, I have it disabled now, and will soon on the car. But I still have the EGR on there just because of the visual inspection every year and I dont want to take the TB and plenum off every year to swap a blockoff plate. Hopefully its fine just leaving an EGR there, just as long as the damn thing does open.

 

If you go with a custom tune chip, you can have it programmed out and keep it in place. There are some tuners on here that would build you one or go with one from TPIS. They can also disable VATS, and even advance the timing some for WOT. https://www.tpis.com/pages/efi

 

I already burn my own chips for both vehicles, both are TPI. I just wasnt sure if disabling EGR via chip was satisfactory enough, or if it had to be pulled as well. If its enough to trick the inspector then Im fine by it.

 

I totally agree. And I use a BB in the EGR vacuum line to disable it.
Come emissions test time, I remove it. The intake passages stay clean.

 

I wish I had the smarts to take a picture. Yes, that's what it looked like, though not so much, and it was behind the pushrods, not between the sets like that.

Definitely something I'm going to have to keep an eye on.

Thanks all for your replies.