new t-stat 180* flushed system new anti freeze. Problem ; after a few heat cycles, temp gauge runs extremely hot on a 50 mile round trip. Shut it down an pop cap, NO anti freeze, res is empty. WTH !!!??????
no leaks anywhere, dont see smoke comin from exhaust
head gasket ?

 

well first off you need a 195* tstat in there. that is the temp at which the computer is looking for otherwise the motor will run rich and you will burn excess fuel.

This could very well be a blown headgasket, whats your oil look like? there is a kit you can buy to pressurize the cooling system, this may help in finding your issue also.

How many miles on the motor?

 

oil looks black, like it needs an oil change.
330,000+ miles, bought 7 months ago, engine had to have been changed, i see scribe marks on hood
havent run the truck in 2 days, popped rad cap, and anti freeze bubbled back out at me slowly
could a new t-stat be bad an i'm losing fluid thru res. ?

 

thats possible, same goes for the rad cap. a compression test may also show a blown headgasket i would think.

 

damn, i'm nowhere near ready to pull this engine yet
theres a new 13 lb rad cap
thx for ur help

 

you dont have to pull the motor

 

i hate doing things twice, if i rip the motor apart to do head gaskets, and pull the motor later to rebuild it, i'll be pissed that i didnt rebuild it when i did the head gaskets. I havent even decided if i'm keeping the 351
this is my project 2011 comparable dually, except, my engine wont only let me do 55 when the whatever fluid is low, or cut the engine to idle only when i'm almost out of that fluid. Ford an the gov. are both smoking crack, like i wanna spend 60k on a truck thats gonna tell me, i cant go over 55 or just idle. To me thats F'in BS

 

if it was loosing that much coolant in a 50 mile round trip, sucking it in blowing it out, you'd surely see steam from the tail pipe sitting at an idle.

Steam readily dissipates once clear of the tail pipe, oil smoke doesn't.

First be sure you have it full to start with.

Turn the temp in the cab to high, no need turn the fan on and then start it up allowing it to get to running temp, add some coolant if needed during warm up to be sure its near full as so to keep gauges sending unit submerged in coolant.

When the coolant in the radiator moves, should be a noticeable difference while tstat is open, stick a finger in the coolant now and then feeling for it to get hot.

Again add coolant if needed as needed during this process so you can see / reach the level in the radiator.

Once it feels hot to touch dipping a finger in it (careful now), you know the tstat is open and the coolant is circulating at that point,.

Now with one hand on the throttle and one with a jug of coolant (can be done by yourself, I do it all the time, but hey get a helper if need be), increase rpms to 1500 - 1800rpm neighborhood and hold it there.

The level in the radiator will be/should be sucked down a ways with the increased rpms, add coolant filling the radiator to the top and put the cap on while holding increased rpm.

Allow to return to idle and fill the remote reservoir little more then half way and cap it, now you know its full with no air trapped in the system. If the system is working as it should be the level in the reservoir will rise while engine is up to running temp, drop when cold but never be completely empty or over full/overflowing.

If the level doesn't drop with increased rpms either the tstat didn't open yet, you didn't wait long enough.
Or you have some other cooling system issue to work out, clogged up radiator, lower hose collapses under engine load and or impeller on pump simply rotted away etc etc you get the idea.

The increased rpms should readily suck the coolant level down in the radiator when up to running temp stat open, if it doesn't figure out why its not.

Once your happy with what you observe, things look good and you know its full, drive it normally keeping tabs on the fluid level in the reservoir (do not take the radiator cap off to check it you will loose fluid and need to add again).
If it drops you find the reservoir low/empty or overflowing you know you have a problem, head/head gasket or otherwise to deal with.

The 180deg tstat will work for testing short term for loss of coolant if you wish but as stated you should change to the required 195* tstat.

 

well done
Rep points to you sir

 

thx for that step by step, i did that before the 50 mile round trip

 

Thank you sir!

Then yea you have problems, if its sucking the coolant in you might be able to narrow down which cylinder or cylinders are effected by removing and inspecting the spark plugs. Any rust on one or more of them would be a major clue but it have to be a fairly substantial amount of water.
However a lack of any carbon deposit on the plugs be another indicator that cylinder might be sucking a little coolant. Easier with plugs been is service a while, had time to build up notable amounts of carbon on them, as water easily and fairly quickly removes it.

 

ok thx, thats what i was afraid of
i gave u reps for ur step by step post