Antifreeze change out along with thermostat question

[StricklandUSN]

From the threads I see when I drain the coolant I should expect 1 and a half gallons my local auto zone says for a change out I need about 4 jugs of antifreeze for a changeout what am I missing. also the thermostat is sticking over past 4 months while driving to work it went to hot for about 5 seconds then back to normal has to be thermostat right?

2004 XLT V6 flex fuel

 

[Exproblems]

From the threads I see when I drain the coolant I should expect 1 and a half gallons my local auto zone says for a change out I need about 4 jugs of antifreeze for a changeout what am I missing. also the thermostat is sticking over past 4 months while driving to work it went to hot for about 5 seconds then back to normal has to be thermostat right?

2004 XLT V6 flex fuel

The whole 2002-2006 V-6 system does hold approx. 16.3 to 18.2 quarts of fluid or just over 4 gallons of coolant. If you have "auxiliary climate controls", you system holds 18.2 qts, otherwise it holds 16.3 qts. If you are doing a complete system flush and fill, you will have to install a flushing T-adapter port into one of your heater core lines so you can hook a garden hose up to it and flush out the heater core and it is recommended to remove the thermostat(then install the t-stat housing cover back into place) prior to flushing out the system to get everything out of the engine block. Install the new t-stat prior to refilling the system. If you do it this way, you'll probably need to refill with 4 gallons of new coolant. If you are just draining some of the old coolant out thru the radiator petcock only, but not flushing out the whole system as described above, you will probably get 1 1/2 to 2 1/2 gallons to come out. Just use a clean bucket to catch the old coolant as it drains and measure how much came out, so you have a general idea of how much new coolant you need to add. If your old coolant is dirty and has a lot of rust and scale sediment in it, I would do a complete system flush and fill, but if it comes out clean looking and little or no rusty sediment, I would do the simple petcock drain and refill, but it's your decision to make. It might be cheaper to buy 2 full strength antifreeze gallon jugs rather than( 4) 50/50 pre-mixed gallons of antifreeze. Use 2 gallons of "Distilled" water to split the 2 full strength jugs into 4 50/50 gallons of coolant. Also, you could have an issue with the t-stat sticking closed and causing an overheating condition or you could have a faulty temp sensor. If the engine truly overheated because of a bad t-stat, you should see coolant from the engine block backing up into the expansion tank and it would be very hot. If it was just a faulty temp gauge spiking briefly and no coolant backing up into the expansion tank or overheating, it could be a faulty temp sensor. BTW, the torque for the t-stat housing cover bolts (3 of them) is 89 inch lbs.

 

[StricklandUSN]

Yes it backed up I'm thinking its the t stat it seems to only do it in mornings when its cooler outside here in San Diego I watched it every 5 seconds and about 3 mins after I got on freewayit went up past half way today but not all the way to hot and then went back to right before the middle mark and 3 miles of ccity driving before nothing it has only done this in mornings for me that's two days in a row same time and drive and you can tell it backed up the first time I'm a bit low from the mark on the tank about a inch . I think it over flowed when it happens previously I have the TStaT I have to buy the coolant how do I know if I have aux cooling or regular if I have A/C in the rear??? So the 4 jugs he showed me where a 50:50 mix?? I want to use the max life high mileage buy two then fill rest distilled? I don't trust auto zone fully lol

 

[Exproblems]

Yes it backed up I'm thinking its the t stat it seems to only do it in mornings when its cooler outside here in San Diego I watched it every 5 seconds and about 3 mins after I got on freewayit went up past half way today but not all the way to hot and then went back to right before the middle mark and 3 miles of ccity driving before nothing it has only done this in mornings for me that's two days in a row same time and drive and you can tell it backed up the first time I'm a bit low from the mark on the tank about a inch . I think it over flowed when it happens previously I have the TStaT I have to buy the coolant how do I know if I have aux cooling or regular if I have A/C in the rear??? So the 4 jugs he showed me where a 50:50 mix?? I want to use the max life high mileage buy two then fill rest distilled? I don't trust auto zone fully lol

If the coolant overflowed out of the Expansion tank when it overheated, it is most likely the T-stat is bad. It's a cheap fix to start with, hopefully that is the problem. Don't drive the vehicle low on coolant, keep it topped off to the full mark until you can change the t-stat. Besides the new t-stat you bought, make sure you have a new "O-ring seal" for it as well. When you remove the t-stat housing, take note of the position the old t-stat sits in and install the new t-stat facing in the same direction as the old one. Also note where the old O-ring seal is located and when installing the new one, coat the new seal with some new coolant to lubricate it prior to seating the t-stat housing in place over the new t-stat. Put a little coolant on your finger and coat the new seal. Don't over tighten the housing bolts, no more than 89 inch lbs using a 1/4" torque wrench. The housing is made of plastic and can crack if over tightened.
If you have AC controls in the rear of the vehicle, I would assume you have rear heat controls as well, but I'm not 100% sure of that. Vehicles with rear heat have an extra heater core mounted in the rear of the vehicle, located under the rear cargo area side panel. I would imagine there would be extra AC/heat vents in the rear of the vehicle as well. My Explorer has a 3rd row seat, but no rear AC/Heat, just front controls. The farthest back AC/Heat vent in my Explorer ends at the bottom rear of the center console. All it means if you have rear heat is to buy an extra gallon of coolant to cover the extra half gallon of fluid that system holds.
On buying the coolant, I meant buy 2 gallons of "full strength" antifreeze, then split them into 4 gallons of 50/50 mix using 2 gallons of distilled water to mix with. I've found it cheaper doing it this way than buying 4 gallons of pre-mixed 50/50 coolant. The pre-mixed coolant is sometimes more expensive per gallon than buying the full strength coolant and mixing it yourself. Check the price difference between the full strength coolant and the 50/50 pre-mixed coolant. Distilled water costs around $1 a gallon in stores. Buying high mileage or long life coolant is fine. Good luck!