I put new FelPro valve cover gaskets on my 1970 442 today. There was no sludge build-up at all. However, on the right bank cylinder head I noticed a grey/silvery, pasty material in the hole at the front end of the head. There also was a real small amount at the back hole. Are those drain holes? I put my finger in it and it was very thick and sticky. I had to use Xylol to get it off. Any ideas? I bought the car when it was 4 years old so I don't know the complete history of it. My educated guess is someone tried to fix something with a bottle of something. I did put put ZDDPLUS twice during two oil changes. The last oil change I did not add anything. The left bank did not show any signs of the stuff. I'm not too happy with this find. The car has been running really great.

 

Just a wild guess. It COULD be something as simple as condensation inside the crankcase mixing with the oil to create a few small pockets of water/oil mix that just got stuck in those specific areas. I've seen similar types of things happen to cars that sit unused for long stretches before.

I know when oil & antifreeze mix, it turns milky white/grey, but could easily be a silver grey from straight water (from normal condensation)

I've seen cars that are only driven short distances over long periods of time (to & from work, etc) and then get out on the highway and get good and hot drop the engine oil capacity as much as 2 quarts from all the moisture burning out. Any time I go on a long road trip, I check my oil level after a couple hours of driving to make sure everything's where it should be.

-Jeff

 

Like Jeff said, its probably and accumulation of condensation and oil emulsion that takes place over time. But you never know, someone could have poured a mechanic-in-a-can product in there too.

 

One of my questions is: Are those holes functional, and if so, where do they lead to?...Or, were they used for the casting process of the head itself?

 

The holes drain oil into the lifter valley. It then falls to the oil pan through some other holes.

 

I've seen this on almost every Oldsmobile cylinder head that had more than 30k-50k miles on it.

I've always thought, due to the way the return holes are drilled, that if there are any small metallic particles from the top end that gets flushed out by the oil, they land there, and are not able to return farther down into the engine. There is usually some guide/stem wear on very high mileage engines, especially if oil change intervals are infrequent, and this would be a natural landing spot for any that tried to return to the pan. I figure that a mix of this and oil would eventually bake here, creating this silvery paste.

Just a hypothesis I never tested.
Not sure why there would be more in front, no matter what it is.
Most of the oil goes rearward due to gravity.
FWIW
Jim

 

Condensation and water vapor can stay in the engine up to 100 miles of driving. That grey pasty stuff is water mixed with oil. I'm guessing you do a lot of short trips in town mostly? I don't think there is anyway around it other than driving farther. Just change the oil more often.