Well this is my first post. I have a d100 with a 225 out of a 72 dodge dart. White sludge in the oil in the first 200 miles I put on the engine. Changed the oil about and put 700 milrs on and came back really bad in the last 100 or so.
No oil in the coolent, doesnt overheat, runs great and heat also works good. I can pull the dipstick and see water drops. Iv read that head gasket failures dont happen evry often. Id hate to have a cracked block are they know for cracking? Its not making oil. Its like its getting condensation from somwhere. Anybody seen this before? Thanks in advance Ian

No, these blocks aren't known for cracking. If you aren't loosing water or oil, then this is normal. You can get one of those exhaust gas detection kits that you fit in place of the radiator cap to detect any exhaust gasses in the coolant if you want reassurance. Should be available at a well stocked auto parts store.

Condensation is normal. You have to drive it long enough to thoroughly heat the engine and boil it off. Not just across town, but say 1/2+ hour on the freeway. Depending on ambient conditions, it can come back in a day or even less.

I drive back and forth to work which is about 90 miles. Engine sees about 175-180 the whole way never going over 180 degrees. I figure thats enough to burn it off. I did notice that the dipstick doesnt seal at the top.

Yep, that's enough to boil it off. If you check your dipstick after a drive I bet you won't see any moisture on it. But... when are you checking it? The next morning? It's 16F with 69% humidity in Angola, Indiana now. May only take hours at that rate to produce condensate. It doesn't matter how sealed the crankcase is, unless its under vacuum it will be there.

Actually thats when I see it is after a drive home from work. Also under the oil fill cap. To me it seems like a head gasket but find it strange its not making oil or using coolent.

Hmm, that is pretty strange. Start with a coolant system pressure tester. You can usually rent them or get inexpensive offshore ones.

Never getting over 180 degrees on a 90 mile drive is not normal. By 90 miles your engine should be up to full operating temp of around 190 degrees. I would check and make sure you have a 190 or 195 degree thermostat. If your thermostat is too cold or not functioning right, your engine can stay too cold and not get hot enough to boil off condensation buildup in the engine.

Slant sixes can run very cool so if you have a thermostat that is too cold it could very well not be getting hot enough to boil out the moisture.

90 may be round trip, but even so for 45 miles I think 180 is enough to drive out crankcase moisture. Besides that is coolant temp, crankcase/oil temp will likely be higher anyway. With that low an ambient temp I wouldn't be surprised to see it not reach thermostat temp.

Considering water doesn't boil until 212 degrees fahrenheit, the engine oil has to get hotter than the coolant by quite a bit. If the coolant never tops 180 fahrenheit, then I suspect that the oil never gets hot enough for the moisture suspended in the oil to evaporate.

I grew up in Alaska where it was regularly 20 degrees fahrenheit and lower. Plenty humid, too. I never saw a properly functioning engine get sludge buildup in the winter. I still say the thermostat needs to be checked and verified that it is a 190 or 195 and that it is working properly.

Assuming a stock oil system (no cooler) oil can (will?) get hotter then coolant, especially under load. How much exactly, no one will know unless you get a separate oil temp gauge/sensor installed. Oil doesn't have anything to directly cool it (rad) or control its temperature (thermostat).

Go for it, check the thermostat, but don't be surprised if its working normally. Remember thermostats don't suddenly spring open at the rated temp, that is just when they are fully open. They will gradually open.

I believe your gauge reading is normal for that frigid ambient, especially if your driving is mostly highway. Heck even here in fair CA weather with a 195 thermostat I'm usually running 180ish on the freeway and it won't rise until I get back into town.

Is your cooling stock? Mechanical fan or electric? Are you using an aftermarket gauge, and if so where is the sensor located? Sensor placement can easily account for several degrees measured difference.

Oil sloshes all over when its running. Even if there is some water in your oil, I have a hard time believing its evident on the dipstick right after a 45+ mile drive regardless of temperature.

You don't have to boil water to have it vaporize - just hot enough to have it evaporate. On that note, is your pcv system intact?

Its a 180 thermostat but I do have a 195 to put in it. The cooling ststem is standered nothing special, doesnt have a clutch fan. The 90 miles is round trip. I have verified thermostat operation. I checked the pvx valve and it doesnt seem to be plugged. The ball moves freely. However I have not checked the breather at the rear of the valve cover. I know the lines not plugged thar runs to the air filter housing but the breather could be. Thanks so much for you guys help so far.

Not sure in a slant six but a typical oil temp in a smallblock is about 120'C ,roughly 245f. That's in a warm climate. It's a known fact that if you grout fill the lower water jacket of a block you get higher oil temps due to the lack of heat transfer to coolant system....so yes,oil will run at a much higher temp than the coolant so any water should be well and truly boiled off I would imagine....but hey, I live in a warm climate and never have condensation issue in oil.... Slant six blocks are pretty thick,but I've seen one crack,the core shift in the casting was pretty bad though. So you mention it's not making oil.....it's not losing water.... Are you positive it's not losing water?? It won't take much to make a mess in the oil....IF it's just due to a cold climate how is your PCV system ? It probably doesn't help keep the crankcase dry when your sucking cold moist air into the engine breather as the PCV valve draws fumes out,maybe plumb a hose so it draws heated dry air from around the exhaust? Like I said,I've only heard people speak of the condensation issue,very interested to hear what the problem really is.

Ball rattling isn't good enough a test - unplug the valve from the cover while the car is running and put your thumb over it - make sure you have a nice strong vacuum. If not, make sure your carb passage isn't clogged and that you have the right carb gasket for the manifold.

Put in the 195 thermostat for good measure. Assuming your other thermostat was functioning (and it seems to be if your temp gauge matched) then it probably won't help your issue though.

Electric fans will help quicken warmup and keeping up temp. You may find they won't even run for you in this weather. I've heard of tales of some folks even blocking half the rad with cardboard or the likes.

Thanks for the oil temp details Steve.

The gauge is a mechanical gauge and it in the normal location at the front of the head.

The coolent level seems to stay the same. For the mess thats in the oil I would have thought id notice a diffirence. I will say the oil is not very warm thinking about it. Iv wiped it bewteen my fingers and its warm but not hot. Not that it makes a difference but the dipstick was also cold when I checked it lastnight after the 45 mile drive. I will check the pcv system when it gets light out. I did just rebuild the carb, its a holley 1920. I also used the thick gasket that came with the rebuild kit, im assuming that is the right one. Thanks for your help guys.