Hi everyone,

I have a 1.6 Fusion+ 2009. I acquired recently.

 

I'm having some issues, I hope everyone can share their knowledge.

Problem 1 is:

So my coolant tank boils over is my main issue.  I've scanned with a OBD machine shows bank 1 sensor 1 heater circuit failure, I suspect this is the 02 sensor located at the back of the engine however not certain if this is indeed related to this.

Problem 2:

I also found my engine rad fan never turns on here's what I've tested so far.

The radiator fan operates (checked with a 12v battery and some wires it does spin and turn on)
The engine fan and AC fuse rear to the battery tested fine with a multimeters,

The passenger compartment relay fuse works fine (tested it by replacing with a 2nd relay fuse for something else:) and faced no issue.

One thing I found suspicious is I tried to then jump the fuse with some wire in the passenger compartment and nothing happened.

I also found that the AC does not operate (light shows when turning on) however I cannot hear the compressor or see the compressor actually running when I have the engine running.

 

My temperature gage inside on the dash always stays in the middle (above 60) and never increases the coolant only boils over when I stop the engine running.

I have had a new engine coolant temp sensor fitted to the right side of the engine no fix so far.

 

I have tested for the head gasket and there's no pressure in the coolant tank only until it gets hot so I don't believe it's that.

 

If anyone has any ideas or what to try please let me know.

I've also tried changing the cap on the coolant tank, no luck.
 

Here is the coolant tank bubbling after a drive (not as bad as previous it's been steaming) 
It shows that it's full-ish in the video (over the max line) however it goes down to below the max line when it's cool. I think it's just the pressure inside the tank.

Wow, that's annoying.  Sounds like someone's repotting mandrakes in there.

The O2 sensor fault is not related to the overheating in any way at all so we can disregard that for now.  

First thing I'd have tried was a new cap so good to see you've already done that.  Did you also check the whole reservoir for any signs of stress cracks, even tiny hairlines?  It may be worth replacing the reservoir if you're not sure.

 

Relays and fuses are two completely different components so I'm not exactly sure what you've tested there?  The AC is probably just empty of gas.  The compressor won't come on if it's empty to prevent damage.  Do you have any way to read basic OBD information through the OBD port?  Even a cheap bluetooth dongle will work for this but Forscan would be best.  Forst thing we need to know is the exact coolant temperature that the engine ECU reads.  If that isn't reaching a specific temp (probably about 97c if this is a single speed fan) then the fan won't come on anyway.

On 11/10/2024 at 7:54 PM, Danymo1221 said:

One thing I found suspicious is I tried to then jump the fuse with some wire in the passenger compartment and nothing happened.

You are confusing FUSES and RELAYS.
From the above line you posted I assume you jumped the relay socket pins 3 & 5 together?
Seeing that you have a multi meter, go back and remove this relay and check that you have 12 volts at the socket of pin 3, this is the easiest way to check that the 40amp fan fuse in the battery fusebox is good. You don't need ignition on to check this.

Next thing to check is the resistance between socket pin 5 and a suitable ground point, it should read a very low resistance (an ohm or 2), if its open circuit suspect the cooling fan resistor.

As Tom has already said, your other issues are unrelated to the cooling fan problem.