Going to need some Thermostat TLC for sure ... It looks like the exhaust is starting to slobber. One or both of the thermostats are MIA or need of some serious TLC....(therma)  STAT.!!!
Sorry could not help myself.
I tried to block the radiator but the fan is reversed and there is no easy access to block the radiator. If I'm going to start busting bolt loose I may as well fix the problem if I can.
Max head temp is 163°F

I'll grab some pics in a bit
 

Well I was afraid of this.....
The temp wouldn't come up over 165°F
I wanted to work on the 8T BUT FIRST: I had to go clear some more downed trees from a windstorm, BUT FIRST: I had to work on the chainsaw ...yada, yada, yada
So I haven't been able to even look at it in the light so took my drone down to take these pics
I haven't seen ANY smoke out the exhaust and I've been keeping a close eye on it.
Last time I checked for blowby (2 starts up ago)  it was negligible.
I'm thinking I've lost a ring, maybe?
I could use some advice here. Please

yes that's starting to slobber bad, hopefully it's not anything more than getting fully up to operating temperature by loading up engine and building some heat
-ring problems are possible but i would guess not likely unless you've feeding a ton of ether etc...
-has engine oil consumption increased dramatically? any other changes?
-does it have a turbo? just wondering if a seal is lost somewhere...etc..

Thanks for responding
No it is natural ex-asperated LOL D318 8T12801 ... not real sure but it looks like a later style thermostat housing 8T14xxx but It was dark, late and cold so I could be way off here.
No changes at all.::: NO ETHER only one time on pony! ...on first start:: The diesel oil is dark and thick (changing before next shift) and holding fast ... haven't checked yet today.
I have a long video on YouTube of it starting the day before I found the oil. I shut it down like normal and it was dark so I didn't notice the oil until the next day ... in the dark ( winter time in Alaska ) saw the oil and sent down the drone during daylight (dusk( winter time in Alaska )) today. It has not run sense I found the oil slick.
temp the day of the start it was 10°F and caught the last few RPMs of the pony as it run out of gas to start the D318 diesel... The D318 has ALWAYS started great even at subzero.

if you want to jump to the grader starting FF to @9:50 and as it was warming up. FF to:@17:34

Sorry ACMOC but I would only have rip up one of your magazines as a LAST CHOICE and besides that Steiner was out dated - ACMOC Magazines never expire...

Many old Cat's will slobber like that if left idling for to long. Put it to work, and most still preform well without a lot of oil consumption.

So yes good thermostats could help. The last new ones from Cat that fit the D318 read made in China. So check the old ones out well before pitching them. In your conditions might try getting a suctions fan so you can put card board on the radiator to help raise the engine temperature.

Thanks Ray54,
I have heard the new thermostats are less then even China's specs so I've been reluctant to grab some. I did look at some early videos of the 8T and saw prior evidence of oil dripping down the muffler but no where close to what is there now.
Found some GENUINE OEM Caterpillar CAT Temperature Regulator (Thermostat) 247-7133
I can't find any kind of conversion numbers for 247-7133 ... Will they fit?
they come in 180° or 190°. I've always used 190° in my vehicles in Alaska

I will not say it cannot be done but the Cat unit are said to be the only easy fitting replacement.

Hummmm: conundrum,
Let me setup a scenario leading up to the events of "The Slobber" and what I think may have happened, how it happened and why. First I left town on the 29th of Dec. for Bellingham WA. Several days later it snowed 4" of fluffy snow at home.Then on Jan 1st a honorably windstorm hit my hometown blowing the fresh snow into a frenzied whiteout. I did NOT put a cover on top of the exhaust flapper valve atop the exhaust before I left the state for 9 days.
 On the way back from town today I noticed more and more trees that had fallen and massive damage due to the high winds.The wind whipped the recently fallen snow into whiteout conditions through the Mat-Su and Anchorage bowl. From Jan. 1st to the 4th, the wind gusts exceeded 91mph as the windchill reached -21°F ...... Blowing over tractor trailers, trees and even damaged a local KFC brick building. At that time I was in Bellingham WA trying to beat feet home.... After I got home, I had some tree cleanup work that had to be done around the house before I could run the 8T.
So I was thinking ... For four nasty days the wind blew and the flapper valve, probably tried to fly south, atop of the exhaust open half of the time, all the while, an amount of snow must have found its way into the exhaust. Settling in hard like a snowdrift. When I finally started the 8T a week after the storm. I ran the 8T harder than I ever had before (trying to see how much heat I could make - no noticeable difference). My thought is the exhaust spit the watered carbon out creating what looks, at first glance, like an oil slick when fact it seems more like a carbon slick from the nasty carbon inside the exhaust. Because the 8T has has a chronic history of low operating temperature the level of carbon in the exhaust and muffler would be elevated.
Changing oil/filters  CAT p/n 1R0659 had one ... picking up 3 more WIX tomorrow
Not sure what the protocol is here but I found some like Part Numbers on ACMOC Discussion Form regarding thermostats; comments by Rome K/G which matched my parts manual 5H0957. Here is the link to the Subject Message
www.acmoc.org/bb/for-sale-wanted-d6/2384...or-thermostat#195521
My best option was hfdzl's suggestion for Gates 33388 @180° ... Gleaning the 8T operating manual(s) I found the lowest operating temperature is supposed to be 170° not the 160° that I was thinking - citing FORM 10492-4
fond one on the ebay the other on the Amazon - Gates 33388

 

Ray54 wrote:

I will not say it cannot be done but the Cat unit are said to be the only easy fitting replacement.
 

I found Squatch253's video on Thermostats (Regulators) finally.    "Caterpillar...... Ep.47: Thermostat Housing;  DUH I kept searching Regulators n Squatch357
Absolutely spot on information about fitting non-standard Thermostats (Regulators).
Thanks Squatch253/nSenior and Ray54