My problem: Tempature gauge seems to not be reading right and my cooling fans are not kicking on therefore causing the radiator to boil over.

Info: Tore apart the inside of the car and replaced the coolant tempature sensor thinking that was it. The car still only reads a tempature of up to just below the halfway line. Not any higher. Tested the original sensor and the new one and they both work correctly. So wasn't brand new junk.

car has 122k miles on it and I bought it off a guy for 6k. its a 2004 6speed manual with the full package. Gps, boise, all that good stuff. It just needed coils, wires and plugs to get it running beautifully. Car body is in perfect condition. Just the fans are my problem.
It looked like the coolant had never been changed. It came out black and chunky when I drained it. I've spent countless hours flushing it and I've gotten it to turn brown now. But I'm running straight water for now until I figure out the fan problem. No sense in wasting money on coolant if its just going to blow out.
Just took out the coolant tank and just ran water through all the hoses. So no blockage.

Put power to each of the two cooling fans to see if they worked. They both turn on and work properly.
Relay's and the 40a fuse are good. I was able to hardwire a fan using the Fan 1 or 2 relay with a jumper. Only problem with that was that the fan kept running after I shut off the car. So I pulled the jump and put back in the relay and both fans came on and ran for 10minutes until I decided to pull all the relays to get them to shut off since I didn't want a dead battery when I got out of work.

But I am just clueless, I've been searching this and other forums for about 3 hours and haven't figured out much. Except that maybe the temp gauge is a fake lol.
Is there another sensor that I might need to replace? I've read something on here about a thermal sensor. But idk if that'd be the case.

Any infomation/help would be awesome

Thanks for atleast reading

 

Coolant temp sensor is in the water jacket near the alternator and SSV actuator.....

If it is reading wrong..the ECU won't turn on the fans

Problem is...the ECU should throw a CEL if there is a big problem with the sensor

Temp gauge doesn't move until the temp is quite high....near 235 or so.....

Check your ECT sensor, the wiring and plug to it....and see if it is OK

 

Yeah I went to oreilly since the check engine light was on. They scanned it and two things came up. Coolant temp sensor reading out of bounds and o2 sensor doing the same thing. So I replaced the coolant temp sensor and nothing else has changed.

With the car boiling over would the gauge read almost pegged out? instead of never moving from its comfy spot just under halfway?
We tried pushing power to the plug to get the guage to move. But nothing happened. Shouldn't something happen if I do that? Or is the car to new? Worked on my 82 mustang.

Sidenote, the check engine light came on again but this time only showing the o2 sensor was bad and not the new coolant temp sensor.
And as odd as this may be, what exactly does ECT mean?

 

Faults on multiple circuits usually involve grounds......

There is a very important ground (for the computer) right behind the ECU cover, under the barometric sensor. A bad ground here would produce O2 and other sensor faults.

I'm sure you've gone over the fuses many times, but recheck the two 10amps marked ENG - these are for the ECU.

S

 

I checked any and every ground I could find. They are all fine

I rechecked those two fuses as well. Perfect

The o2 sensor going out was a cause from the Cat being melted from the previous owner. I just gutted the Cat and bolted everything back.

The car is drivable, just boils over everytime. So everyday I have to add about a 16oz of water. Which is annoying because then I can only beat on it like once everytime I drive.

The coolant temp sensor connector, It still reads a tempature up to just before the halfway line. So I'm assuming that the connector is good.

Any and all ideas are welcome. I'm stumped.

 

Check the belt tension (water pump ), t-stat (for opening all the way) and also have the radiator flow tested. If those check out you may want to have a look at the water pump. You need to get "coolant" back in it as running straight water will cause even more damage.

 

^ Concur. There are inter-related systems in this case. First ensure you're getting coolant flow. The radiator could be 'air bound' (somewhat similar to air bubbles in the hydraulic lines). If the flow is poor or non-existant the coolant temperature sensor may not be rendering an accurate input to the ECU so the fans are not coming on which is compounding the problem.