Gray sludge in oil pan

[Bjv69ss]

I started to tear down my 350 today for overhaul.  When I got the oil pan off under the black sludge was "battle ship gray" sludge.  What does this indicate?  When I drained the oil from the crank case it was very thin as if it was diluted with gas.  Could this gray sludge be the result of a Rochester 4bbl that is leaking?  The crank and rods look as though they were washed...  Nice and clean!!!
Thanks

[hotrod68]

The gray stuff usually indicates condensation. If an engine is started and run a short distance before it fully warms up on a regular basis, then shut down, you'll get the gray sludge. That's one reason short city driving is so hard on engines--they're driven 2 or 3 miles cold to work and back and the condensation never gets burned out of it. Hope this helps. As for the black sludge, if it's caked on like frosting there's a pretty good chance the old owner used Quaker State oil!  Just kidding.......

[Bjv69ss]

Thanks for the info. There's no hard caked on sludge inside just the gooy stuff.  It won't get Quaker State the second time around that's for sure. 
Joe

[Farm Boy]

If it’s gray and in the bottom of the pan under the oil it’s material from the bearings.

[Steve68]

Joe

Have you been a long time user of QS oil?  Why do you say that you won't get QS the second time around?

Steve

[JohnZ]

Quaker State hasn't used their old "Pennsylvania Crude"-based formulation for almost 20 years; they use the same base everyone else does, and meet all the OEM,SAE, and API test requirements.

[lakeholme]

John  is right, but the Q is still fighting that bad rep.  When I bought my 95 S10 I took advantage of their life of the motor offer.  200,000 miles later and she runs stong and clean, no drips, no errors.  I wish they'd run that promo again!

[KurtS]

To explain this a little more:
PA crude oil contains parafin. Very little crude elsewhere in the world has that.
QS didn't filter enough of it out and it would build up in the engine. I've heard of valve covers coming off that looked like a jello mold - just enough room for the rockers to move!
Pennzoil (and Wolf's Head) used the same crude, but they filtered more of the parafin out, so it wasn't an issue. I have some of the stainless wire they used in the filter house laying around.

[Steve68]

Kurt

Why do you say that QS didn't filter enough of the paraffin out?  Penn grade crude oil is widely recognized as having a natural lubricating property to it.  That property is the paraffin.  If the oil met spec's then they left the proper amount to obtain what other non-Penn grade crude could not provide.  Any gray "stuff" would be found using any oil as it is caused by blow-by gasses.  BTW, not all of QS refineries used wax houses (wire filters) either.  QS, if I'm not mistaken, is now made by Shell.

Steve

[KurtS]

Well, I'd say that having buildup in the engine says they didn't remove enough, hence the reputation from days of old.
Pennzoil used the same PA crude, same advertising, and didn't have the issue of buildup.

The stainless wire that I have is what retained the filter, btw.

[Steve68]

The sludge like stuff you see when you remove the valve covers is the result of blow-by gasses mixing with the oil.  This would occur using anyone's oil and did back then.  I don't want to be the QS champion on this but they did get stuck with an unfair reputation.  In fact, QS was the number one manufacture of motor oil in the U.S. for many years.  If it was that bad I don't think people would have been buying it in that quantity. 

As I recall the filters were made up with a fabric that was pulled over a large ring and held on with the wire.  These filters were placed one after another on end in a very long line.  Wax houses used reduced temperatures to get the wax out.  Ammonia was used by most of the QS plants wax houses to accomplish the cold temps.  As the petroleum was passed through the filters they collected the wax.  After the process, a worker would separate the filters and take a steel bar and hit each one to knock the wax off them.  The wax would fall into a trough and would be further processed into other products.  What went through was one half of the base stocks used to make the lube oils.  If this base stock did not meet spec it was "re-run".  If it did then it contained the proper amount of lubricating properties (wax) and was used.

Steve