Focus overheating today

Pew

Joined
Mar 12, 2018
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Hi folks,

So my 2015 1.0L focus with ~208K miles is overheating right now. I drove to work and back home this morning just fine (2 hours total, light traffic ~70mph). It's 85F with 66% humidity and the temp gauge with the AC off stays at/under the halfway mark but when the AC kicks on, the temp rises above the line within 20 seconds and I lose almost all power. The power will come back and the temp gauge will drop again if I turn off the AC.

At a stand still with the AC off the car's fans will kick on at full blast within 30 seconds. Both feed and return coolant hoses are hot and the coolant reservoir is full. No check engine lights and all maintenance is up to date and the water pump was replaced via warranty around 33K miles. On occasion a P0420 will come up for the O2 sensor but no other CEL.

I'm in the process of draining the 10K old coolant and replacing both thermostats with motorcraft (RT1242 and RH242 coming in Wednesday) since I have issues with the car keeping temp at/below freezing. Is there anything else I should be looking at for what could possibly be causing the issue?

Not sure if this matters but the AC was blowing cold air all day until I shut the car off for a minute at UPS. Then it started blowing warm air and the car felt like it had 20hp. The AC is whines up and down with the RPMs too after I drove the car through a puddle that was a bit too deep a couple years ago. I've had the AC stop blowing cold air about 10 hours into a road trip last fall but started blowing cold air again if I turned the AC off for a while. The indy shop I took the car too after that event said the AC compressor/clutch was fine.
 
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I’m thinking radiator—sounds like it cannot shed heat. Why i don’t know.

if a bad water pump I wouldn’t think both hoses would be hot.
 
Do a coolant system pressure test, that happened to me once and it was a head gasket leak due to head warp. Coolant reservoir was full but the cap malfunction (Gate / Stant) and stuck close.

86F isn't even that hot so it shouldn't have any sudden failure unless something is wrong.
 
i recently cleaned out my radiator and AC condenser fins with SIMPLE GREEN solution and my water hose to get out the road dirt and dead bugs to aid in cooling
 
Sounds like a thermostat gone bad. Is that the original t-stat with 208,000 miles? Mine have all failed around 150,000-175,000 regardless of vehicle make.
 
Thanks for the replies folks. I'll order the temp sensor and rent a cooling system pressure tester from autozone as well.

Sounds like a thermostat gone bad. Is that the original t-stat with 208,000 miles? Mine have all failed around 150,000-175,000 regardless of vehicle make.

Correct, it's still the original factory stat. I figured it'll be almost time to replace it anyways but I only ordered one earlier this year since I didn't realize there were two stats on this engine.


You said the reservoir is full. But you should also check the radiator because it may not be drawing coolant from the reservoir.

It's draining now via a petcock valve at the bottom of the radiator and the reservoir drained at the same time. Could that confirm the coolant is flowing through the radiator or is there another way to check?
 
Does this version have active grille shutters? If so, I think there’s a way to lock them in the “open” position.
 
Does this version have active grille shutters? If so, I think there’s a way to lock them in the “open” position.
Yep, the shutters do actively open and close (confirmed by having the defrost/AC on while warming up.)

Sounds like your compressor may be bad. Start the car and turn on A/C and listen to the compressor.
I did the hold-a-screwdriver-to-it-and-listen-to-the-other-end last fall but the indy shop I took it to after said everything looked good. I might have to bring it back to them to see if it's still good.
 
if you are ordering all this try rock auto.. much cheaper, more options/better parts.
 
Thanks for the replies folks. I'll order the temp sensor and rent a cooling system pressure tester from autozone as well.



Correct, it's still the original factory stat. I figured it'll be almost time to replace it anyways but I only ordered one earlier this year since I didn't realize there were two stats on this engine.




It's draining now via a petcock valve at the bottom of the radiator and the reservoir drained at the same time. Could that confirm the coolant is flowing through the radiator or is there another way to check?
Feel the upper hose when it's cool and running. Once it hits the thermostat opening temp you will feel the coolant in the hose moving
 
Would anybody happen to know what this part is? It's bolted into the block from a hose connected from the reservoir to the engine block (part 10 in figure below.) I took it off to get one of the coolant hose clamps off and when I pulled it out, it came apart in two sections.

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1625514316361.png
 
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