04 Expedition EB 5.4L - fail safe mode problems (or cooling problems)

[Fat Slob]

I have 04 Expy with approx. 190k miles. Engine was replaced with 5.4L Jasper about two years ago (35k miles on it give or take)...

Most of the coolant leaked out so firestone replaced the cracked hoses and thermostat about 2 months ago.

Since then, truck has intermittently gone into fail safe mode, always on highway at 60mph + it seems. After resting a few minutes truck does start and runs as normal and sometimes shuts down again and other times it makes it to destination no problem. It was having the same issue even before the hose/therm repair was done if I remember correctly.

AFTER firestone replaced all that, I had a puddle of coolant in my driveway on one and only one occasion. After refilling it there has been no leaking and level has remained constant. I brought it back to firestone and they did pressure test on whole system and said everything looks and tests fine. Mystery.

Any suggestions on what I should do/try? Greatly appreciated.

 

[stamp11127]

Has it run hot before going into limp mode? Have you burped the cooling system since refilling it?

 

[Fat Slob]

Has it run hot before going into limp mode? Have you burped the cooling system since refilling it?

Hi Stamp thanks for reply. No it hasn't run hot and isn't hot when it goes into limp. Temp gauge normal and no visual signs of overheating when I look at the engine (no smoke etc). I don't know what burp the cooling system is but I can definitely try it. YouTube warrior.

 

[stamp11127]

Air gets trapped in the cooling system and can fool the temp sensors.

I usually just have the car parked uphill on a steep incline so that the surge tank is the highest point and fill. Run up to temp and squeeze the upper rad hose a few times.

 

[Fat Slob]

Air gets trapped in the cooling system and can fool the temp sensors.

I usually just have the car parked uphill on a steep incline so that the surge tank is the highest point and fill. Run up to temp and squeeze the upper rad hose a few times.

Can I do this after its already filled?

 

[stamp11127]

Yes you can, also as the coolant is warming up. It will get to the point of being to hot to handle. Stop before that point.

If you have a scanner that can read individual sensors, monitor coolant temp and cylinder head temp if it is equiped.

 

[Fat Slob]

Yes you can, also as the coolant is warming up. It will get to the point of being to hot to handle. Stop before that point.

If you have a scanner that can read individual sensors, monitor coolant temp and cylinder head temp if it is equiped.

Thank You, will try it.