Steam or condensation

[stu’s68furyiiirat]

I have a 68 furyiii 318 changed intake gaskets and changed the oil looks like steam coming out of pcv valve side of valve cover spark plugs looks dry and breather on valve cover has steam coming out of it to any suggestions would be great before I tear down and replace head gasket etc also weather is around 55 degrees

 

[CBODY67]

"Steam" with the engine cold, during warm-up, or at operating temperature? You have to understand that whenever the block warms, that heat will tend to evaporate any latent or residual condensation within the crankcase . . . as a NORMAL activity. In cooler weather, even with "more tuan 10 mile trips each start cycle", the LA engines tend to run cool so you can even see a white gunk at the top of the dipstick and even clog the pcv hose behind the carb (where it can tend to sag) . . . as my '80 Newport 360 2bbl has tended to do in the winter months, even with a 180 degree F thermostat and a good-working heater.

As long as no milky motor oil, no coolant-fouled spark plugs, and no coolant leaks, it could well be that what you are seeing is normal, very possibly.

Just my experiences,
CBODY67

 

[Slap Stick]

Later LAs use a 192° stat. That is why you see "mayo" with a 180.
As for "steam" coming from the pcv and breather ensure it isn't blow by from the crankcase.

 

[Big_John]

I have a 68 furyiii 318 changed intake gaskets and changed the oil looks like steam coming out of pcv valve side of valve cover spark plugs looks dry and breather on valve cover has steam coming out of it to any suggestions would be great before I tear down and replace head gasket etc also weather is around 55 degrees

You can do a compression test before pulling the engine apart.

I've never seen a lot of steam coming out of a valve cover, so I'm thinking it might be blow-by from the crankcase. If it is, it will be an oily, smelly cloud that kind of pulses with the engine. Possible cause are bad rings, pistons, and maybe a bad head gasket.... Or any combination of those.

Possibly a better test might be a leak down, but I'll bet the compression test will tell you what's going on.

 

[CBODY67]

Later LAs use a 192° stat. That is why you see "mayo" with a 180.
As for "steam" coming from the pcv and breather ensure it isn't blow by from the crankcase.

The 1968 Plymouth FSM states that all non-Slant Six engines use a 180 degree F thermostat. Only reason for the 190-195 degree F thermostat in later years had to do with exhaust emissions only. So, with that information, a 180 degree F thermostat in my '80 360 2bbl V-8 is fine. It only causes those issues mentioned in cold weather, in "normal" trips to work, back, and where ever. That same FSM, in bold print, cautions against a 160 degree F thermostat.

In many fully-computer controlled engines, the factory spec thermostat is necessary, many times, so the ECM will go into feedback loop mode for engine management purposes. And earlier Chrysler systems seem to be in that mix, too, from what some magazine articles in the 1990s mentioned.

Enjoy!
CBODY67

 

[70bigblockdodge]

Borrow/rent a tester to see if combustion gasses present in cooling system.