99 4.0 Ranger check engine light problems

[Theurbanangler]

My 99 4.0 Ranger has the following code popping up that is giving me trouble : P1025.

I know that it's a code for not being able to get into closed loop cycle but would that be cause by the thermostat? How challenging would that be to replace myself?

Also the oil tempature gauge will not go above the minimal line even when running for an hour. Making me feel like the thermostat is stuck open allowing coolant to flow more causing the code and low temp on the gauge.

Unrelated to the problem, I think, when I turn off the engine there is a gurgle or bubbling noise that happens in the engine and I'm not sure if that's from airbubles being trapped

Would be much appreciated if someone could give me some advice or let me know if I'm on the right path.

 

[Mark_88]

Before doing anything else, test the system for air/fluid leaks. It can save you some time and wasted effort if you determine that first...

Get a latex glove and with the engine cold remove the rad cap, stretch the glove opening over the rad cap...remove the coil wire (so it won't start) and crank the engine.

Watch the glove...if it blows up or even puffs up while cranking there is a good chance you have a head gasket issue...

The gurgling sound means you have air in your system...meaning the system needs to be burped (get the air out) and topped up...which could mean something else is going on...like you are losing fluid somewhere...either a leak or something wrong with the head seal.

 

[Mightyfordranger]

Another option is head to your local autoparts store ask for a cooling system pressure tester itll come in a box with a little bicycle looking hand pump read the directions and go from there the pressure u want to fill it to is whatever your rad cap is rated to and if it won't hold the pressure start hunting for a leak little air bubbles also most ford theromstats when they fail they stick open where as GM stick shut

EDIT: you should just be able to rent it like any other tool