I will also mention that when I changed the oil last time it looked fone. None of the sludge drained out and I changed hot. I mean 2 minutes after my drive from work.

I know this sounds unlikely ,but what is the oil level? Is it possible you changed dipsticks or something and it's over full? It's weird that the oil got hot quickly prior to the oil change...I'm not suggesting running an abnormally low oil lever,but if it's over full the oil will obviously circulate less often and sit in the sump longer and stay cooler,.... I did say long shot!

I put 5.5 quarts in it. The pan came off an 81 slant six that I have awating a rebuild.

You mention, you replaced the carb gasket. I would check and make sure it is installed correctly. The small hole in the gasket must match the small hole in the manifold. If it does not, the PCV will not function, and you will get condensation in the oil.

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
64 Valiant Signet
64 Valiant 4dr 170
64 Valiant 4dr 225

I commuted in a couple of Darts with /6's in central and northern IN for 7 years; getting the operating temp up to normal can be a challenge, even in 1/2 hour of 45-60 mph driving or even on the inerstate. I even had to put cardboard in front of the radiator in my 76 Dart Lite to get reasonable heat out of it in the dead of a couple of cold winter snaps in IN. But I never had condensation issues with commutes of 20 miles and 40 miles each way.

So the 180 degree coolant does not surprise me at all. I think this particular vehicle is just going to have a lot of cool air flowing over an engine that has low heat/power output.

BTW, winter weather in IN tends to be pretty dry; when living there, our heat pump often ran down to 15 or 10F there and did not freeze up the coils. So, don't take other area experience with moisture as being representative of what is going on here. That tends totell me that it is a specific issue in this engine: coolant leak or PCV or..... The oil and dipstick being cold after a long drive says that the oil is just too cold. That is really odd. I almost wonder if the assembly lube from the rebuild is coagulating out....?? (Another long shot)

The cooling system pressure test in this case is an absolute must; don't fight doing that, just get it done as a first step. Coolant loss can be pretty slow and yo umay not have detected it yet. Some auto parts store in your area might have one to loan out or use right at the store.

Then try the 195 F t'stat. Check all the things suggested around the PCV...and make sure the PCV port is not plugged; that is not uncommon, and hence the instructions to check for actual vacuum not just a rattle. Finally, try some cardboard in front of the rad.

BTW, what rad do you have in this vehicle? Is it perhpas one for a V8? If so, it may actually be cooling too well.

Well i warmed it up and did a pressure test and it didnt hold it, cant find it leaking anywhere. Pcv seems to system seems to be ok. Thanks everybody for you help, gave me a lot of good info.

Sometimes its tricky to get the cap itself to seal and takes some fiddling. If your tester seals on the surface pointing up vs the circumference then you may need to just hold it down.

Oil gets hotter then coolant but warms up slower. If your saying you changed the oil hot, and you were able to handle it without burning yourself, then yes the oil just isn't getting hot enough.

Seems to hold pressure fine cold. I do have a v8 radiator, could that be too big and overcooling?

Your thermostat temp matches your coolant temp, so no I don't believe an oversized radiator is the culprit here.

So it holds pressure cold but leaks when hot? I'd run the test again and clear that issue up before going any further...could be a crack or head gasket. Like Pierre said,if your thermostat is working,and it seems to be the case,then a large rad won't be the issue. You could cover the core as an experiment,just to prove it's not an issue. When it's hot,does the cooling system hold pressue when you turn the engine off or does the pressure bleed off quickly? Even just test it by using the standard cap and squeeze the upper rad hose.

The block never warms up enough to get rid of the sludge.

I always had to use a cardboard rad cover if the temp got much below freezing on my A bodies...even with a 195 thermostat.
Its not just the rad you are covering. You are also keeping the cold air from cooling the block. Sixty five MPH at 25 below zero is a lot of cooling.

I would definitely get a 195 thermos stat. Your car will run a ton better.

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Yeah....Im the one who destroyed this rare, vintage automobile.....

It doesnt hold pressure when hot. I squeezed the top hose before and its not hard, did it last night before I pressure tested it. Didnt fall off fast but about ten minutes it lost five pounds with no external leaks. I pulled the head today due to valves and rocker arms being pitted. Number six has a scratch I can feel with my nail. Head gasket looked ok. Its my daily driver so ill have to drive my 4x4 in the meantime. The 81 needs a cam and lifters might see if I can find a set and put that engine in.

It had a scratch where?

This was a truck right? Plenty of air could be flowing underneath too and cooling the sump. Consider electric fans too - will prevent air circulation until its actually needed.

Sorry #6 cylinder wall.

Ya it is a truck and I think electric fans are going to be going on as soon as I can figure out what im going to do. I thought about pulling the piston and sanding it out but I really want to do it right and pull it strip it and hone it.