I was thinking the temp sending unit(ECT sensor) maybe but why the puking of coolant?

It doesn't run hot though. It just jumps to hot on the guage and goes back to normal after shutting the engine down and immediately turning the key back on. (Watch video). So the fan really isn't suspect.

 

Ok, I am looking at the service manual and I just realized that there are two things that I may have been confusing. There is an Engine Coolant Temperature Sensor and a Sending Unit for the Water Temperature indicator.

What's the difference between the two? Is one just for the guage and the other for the ECM?

 

Lemme look

 

One opens the tstat?!!! The thermostat is a mechanical, old school device. Please elaborate.

 

The water temp swing unit is for the gauge. I Messed up one doesn't open the tstat
The other ect changes resistance as the temp increases.

 

http://www.justanswer.com/ford/0s0ua-variable-run-time-start-trip-97-f150-will.html

This link pretty much covers my symptoms. I haven't noticed heater issues but it's summer and I haven't been using the heater to find out. I also haven't noticed his hissing symptom.

One other thing I forgot to mention was that I used some Liquid Aluminum™ Cooling System Stop Leakto temporarily fix a leaking radiator because I couldn't afford to replace it at the moment it started leaking. It went a few weeks like this. Could this cause some intermittent blockage as listed in the answer below? I've easily gone through 15-20 gallons of coolant during this whole process. Always using new coolant and distilled water.

What it doesn't explain is why it happens only once per cold start cycle. Would the odds say it would re-block the coolant system periodically?

 

Sure sounds like a leaking head gasket. It may be leaking more when engine cools off and metal contracts. I use a C02 detection tester to verify blown head gaskets. It uses a chemical which changes colour when C02 is present in the cooling system. If you have a blown head gasket you WILL have C02 in the cooling system. The tool cost around $70 here in Canada. Money well spent to be sure-even if it does reveal the news you didn't want.

 

I bought the Engine Block Tester yesterday. I plan to test it for combustion gases after I get home tonight.

On a different but maybe related note, I have a "gurgling" sound coming from the dashboard behind/beneath the radio, hvac controls. Some searching says it could be air in the cooling system. Could it also be if my AC needed a recharge?

I would also ask for suggestions for removing air from the cooling system as my methods haven't been working.

Thanks

 

Ok, the test for combustion gasses in the coolant came back as negative. That eliminates the cracked block/head or leaking head gasket.

So, I am down to air in the coolant system. I'm still looking for a good technique for getting them out of the 4.6 L Ford V-8.

Thanks.

 

Anything? Techniques for getting air out of the coolant system?