I hear ya, I would still pressure check the cooling system. It could be a hydraulic pump leaking into the crankcase, or the P/S pump.

Usually (every time in my experience of 30 years) when a continental flat head has a faulty head gasket, there is a compression loss in 1 or 2 cylinders. I've never had a coolant leak into the crankcase, but there's always a first.

Last time before I changed the oil the level was very overfilled. The level had not gone about full while I left the radiator cap loose.

I would pressure test the cooling system before condemning the head gasket. Usually the oil turns a milky brown color, not green.

If you constantly run a continental engine in short spurts (5-10 minutes at a time), the oil will get moisture in it because of condensation inside the engine.

I have a Clark C500 with a 6 cyl. Continental. The oil level has been going up lately and getting green. Changed the oil and loosened the radiator cap. I do not run it for very long at a time where it could overheat and the oil was looking good. Last week I tightened the radiator cap again and noticed the oil is starting to get a green color again. Head gasket or any thoughts?

The old c500 wakashau 4 cyl and f163 I think used a zenith or J&S high pressure system for propane make sure the carb is ok if you are using one of these systems they will drive a fella nuts.

Yes it needs a thermostat. I've started using Gunk engine flush to clean up the block and head after a blown head gasket repair. I find it works great to clean out condensation/ AF from a leaking head gasket.

It would do well to make sure it even has a thermostat in place (and working correctly).
It's entirely possible someone removed the thermostat altogether at some time if chasing an overheat problem.
I remember back in my younger years I sometimes heard somebody say "Just leave the thermostat out, **** it doesn't need one until winter."

thanks.

Compression checks out good- no head gasket issues. Change the engine oil ( I reccomend SAE 30) & run engine at least an hour- let the engine get good & hot. Do this on a weekly basis & it'll bake the moisture out of the engine.

The propane system sounds like it's time for a rebuild. Make sure you're running HD-5 propane ( if you want to keep your propane system clean for as long as possible). I reccomend replacing the propane shut off solnoid, regulator & carb diaphram- total cost is under $500 (if you replace these items yourself). That should keep you up & running.

ok here are todays results... compression is consistent between all 6, between 138-140psi.

also in regards to the throttle issues, if i push the primer button in on the propane valve under the hood, and then throttle it, it's revs up normally.

maybe i am just looking at moisture?

and concerning the brakes...not worried about that right, thats for another day :-) right now it's the water in the oil. and throttle...

Flat head engine are low compression -not sure of the exact number. The important thing is that the numbers you get are consistent. If 2- side by side cylinders are extremely low, the head gasket is gone.

As far as the 30% throttle issue, could be ignition or fuel. Describe the fuel system (I'm assuming propane), different types have different symptoms. Does it have a choke cable? The fuel line should go from the propane tank to some type of fuel shut off, with a wire or vacuum hose going to it. From there it should go to a regulator, either in the same housing as the thermostat in the upper radiator hose, or off to the side with 2 smaller hoses going to it. from there the hose should go to the carburator. Which of these systems does your truck have?

As far as the muck in the radiator, run some radiator cleaner through the cooling system & see what happens ( you may find a leak, you may not - sometimes folks use "stop leak" in the cooling system which will eventually turn to a muck at the radiator cap- but not always)

As far as the brakes, what are they doing? Your truck has a power booster & disc brake setup inside the rear housing assy. Not a complicated system, just an expensive & time consuming one to service.

trying to add some photo's of the engine but, can't seem to... :-/

ok, i will do a compression test tomorrow. what should a flatbed compression bed? (i've never touched a flathead before), also the exhaust has a large hole in it...and if the seat were left up water could have gone right in through the hole.

the engine runs fine at low rpm but dies if you go over....30% throttle?

also i noticed on watery condensation looking stuff in the radiator filler neck.

i just want to get this thing running good for my use. the hydraulics are strong, brakes....could use some work but, the hydraulics are strong.

Right, bbforks, there really is no way to get water in the oil with a flathead motor. A compression test is a must to prove the gasket is bad.

Before you do anything, change the oil. these engines are notorious for loading up with condensation in the oil from frequent & short running cycles. Change the oil & let it run- if it needs a head gasket it will run rough (with a miss). I personally haven't seen a continental engine loose coolant into the oil because of a faulty head gasket.

If you do pull the head, make sure you have the head resurfaced- don't skimp here- you'll only have to do the job twice if you do.