I was stripping down a 5.8 tonight, getting it ready for the machine shop. I've personally never seen grime and sludge built up so bad. Certainly explains why the oil pump was going.

Just thought I'd share. looked much worse in person.

 

When I bought my Van the Motor looked similiar - but way not that bad.
The sludge was just in the oil pan and everything else was covered with a layer of charcoal.

Even with new oil - you can pour fresh oil in and it runs black out - withoiut even one spin.

Here's a pic of my oil pump and rod bearings - you can see how worn they were



I wonder what yours might look like...

 

The only time I've seen an engine look like that on the inside was when coolant leaked into the oil. AF & oil do not play well together.

 

Looks like an engine that has run valvoline.

 

Surprisingly enough, everything was in pretty decent shape considering all the sludge. The motor has 130k on it, ran really well and felt plenty powerful. I'm curious to know exactly how all of it accumulated, it's a half inch thick in some spots.

 

I've seen worse. One 302 I pulled apart had sludge that filled the lifter valley completely, the bottomside of the intake was molded in revese when we pulled it off. This used to be a common sight when ND or Quaker State oil was used. Also happens when no thermostat is run for long periods of time in a vehicle that's nevcer driven far enough to get the engine hot.

 

Wow I thought my 5.8 I just tore apart was mistreated. Still doesn't beat an old honda I had I never went past the valve cover but the rockers were surrounded in a loose black cake that filled the whole valve train area. Sucked it out with a vacuum put the cover back on and kept driving.

One of these days I should get to see the inside of my old 91 escort. I bought it off a crack head for $100. I literally found crack pipes and needles hidden in the thing. So you can guess how it was treated. It has a sticky lifter everytime it started making noise I'd rev the thing out in 1st gear til it bounced off the rev limiter. Noise would go away for a little while. Sold it to my buddy after 2 years he beats her just the same no oil changes just top her off. Still runs like a champ.

 

It's amazing how resilient some motors can be. My father in law has a 96 Mazda pickup with the 4.0 he bought almost new. Since then he changes the oil every 50,000- 60,000 miles with full synthetic. Now at 270,000 and driven very hard on and off road it just keeps going with nothing but general maintenance along the way. I wouldn't try that myself but it's hard to argue with results.

 

The oil pump is probably fine. The pickup screen gets mostly clogged with that debris, resulting in oil starvation.
I have also found that engines will amazingly survive a lot of this fouling. I removed the oil pan of my old Escort because the oil light started to come on, and testing showed indeed that the oil pressure dropped right off at higher rpm.
After cleaning everything up and reassembling, it ran fine and a faint rod knock that I had been hearing for a long time disappeared.

I did plastigauge the rod bearings and found them all acceptable but at the high end of tolerance. I guess that means they were at "high performance" clearances.

I also agree that a failed (or too low) thermostat that prevents an engine from heating up properly will aggravate this.

 

I wish I still had the pics of my 351 when I tore it apart. My 96 I am 2nd owner of 1st guy ran nothing but valvoline, same with me but full synthetic started at 10w30 now 5w30. I swapped to gt40P heads etc. engine had 183k on it the inside of the original heads that are sitting in the garage have surface rust now they looked new, bearings were fine, pump fine, all gaskets were ford oval stamped and part # so it had never been apart and paperwork I got with the truck never replaced, cylinder bores rings fell in at 12-14tho. for the new ones.

2 big things to contribute to sludge(aside from cheap junk oil) too low temp thermostat and too high of a weight oil. I use to work on fleet vehicles trucks were all GM gen1 small blocks that ate conco 15w30, those pics of that W are ugly but I have seen SBC that I had to peel valve covers off and had a rocker arm moving in hardend crap. Oil draining back down pushrod holes and only reason it became known it was a issue was the truck was detonating so bad and smoking just sitting in area of valve spring leaking past stem seals and just junk.

Ask anyone that owns a newer GM truck that loves Amsoil what they think of it in their LS based engine with VVT or cylinder shut down. Friend of mine 09 5.3 GMC, GM replaced it 2 times before 50k after 2nd one went in they told him don't use Amsoil anymore or next one is on you. The 25,000 oil changes turn to thick nasty sludge that makes its way to the pan then pick up where it stops the pump.

Curtis