Engine Temp Gauge Broken

Bronc95
Jul 09, 2020

Rank 0

Jul 09, 2020

Hello all,
I have a 1995 Bronco XL (302) which I just bought and I have been having some issues! The engine temp gauge immediately reads that it is overheating even when its been started in 40 degree weather/cold started. Aka the gauge just sits up there. I assume the gauge is just broken or maybe there is much much more to it. The previous owner was very hands-on thankfully and changed the temp sensor, I flushed and changed the coolant... running out of ideas. Could it be some wiring issue? Thank you for the help.
Last edited by a moderator: Jul 09, 2020

Rank VI

Jul 09, 2020

#1
How did the coolant look? Most people do not use distilled water to fill the radiator.... and if you use tap water guess what.... There is always an acceptable about of organic material for free. This organic material will start to become cloudy and eventually cause some clogging issues. Are you sure the Bronco is overheating? There are a couple of shade tree checks. The upper radiator hose will be hot if the thermostat is opening. If the upper radiator hose is just warm after running up to temp then the thermostat might not be opening. When cold ( do not open cap when hot) you can open the cap and see if the fluid is actually moving. If it is not moving the water pump is not working. Also make sure you are getting hot air through the heater. If the temp gauge goes up it should come back down if you turn the heater on full force.... you are essentially running it through another radiator in the heater core. I always hated the factory gauge. I replaced my sending unit and went to Lowes and bought some plumping tees and installed a real temp gauge along the factory one. That way you still get a idiot light if it runs hot but have a secondary gauge for the actual temperature.

Check for leaks and water level.

Good luck

Keeping the engine cool is most important thing for long life. If I even think my engine is getting hot the heater comes on ASAP to try to keep her cool.

Rank 0

Jul 09, 2020

#2
Hey Paul,
Thank you for the kind message. Last weekend I drained the coolant (which was very green) and then used distilled water through the system. I have to add a few steps with what you mentioned. The previous owner installed a newer temperature gauge but it died. We shall see! I will update you.

Rank 0

Jul 09, 2020

#3
I would see if you can get a cheap gauge to see if it is in fact the stock gauge that is the issue. The gauge cluster are easy to remove and replace gauges. eBay or a local u pull it might have one you could also try.

Rank 0

Jul 12, 2020

#4
Sounds like a bad gauge to me

Rank 0

Jul 13, 2020

#5
Hey there - This a common issue. The thermostat likely needs replaced. They get stuck open. Motorcraft is the best bet for OEM replacement
Tack Hammer

Rank 0

Jul 14, 2020

#6
Sounds like a wiring issue, if a gauge reads full that means there is no resistance. I believe this is a one wire circuit so that probably isn’t shorted. Pull put the instrument cluster and look at the wire traces on the back, something might have burned up. Also are you sure he replaced the right sensor? Mine is a 351 not a 302 so I’m not positive if yours is the same but mine has two coolant temp sensors, one for the pcm to read and one for the dash

Rank 0

Jul 14, 2020

#7
Sounds like a wiring issue, if a gauge reads full that means there is no resistance. I believe this is a one wire circuit so that probably isn’t shorted. Pull put the instrument cluster and look at the wire traces on the back, something might have burned up. Also are you sure he replaced the right sensor? Mine is a 351 not a 302 so I’m not positive if yours is the same but mine has two coolant temp sensors, one for the pcm to read and one for the dash
It is a shame since I just got the vehicle... owner said he did in fact change it but he may have changed another one. Who knows.

Rank VI

Jul 15, 2020

#8
Hey I gave you some bad information. I actually bought the thermostat housing with the port to install a temp gauge. This is a very good mod and gives you the temp right after the thermostat. Worth the money.


https://shop.broncograveyard.com/85-94-302-V8-Thermostat-Housing/productinfo/30640E/

IMG_2620.jpg

Rank V

Jul 25, 2020

#9
I had a similar issue in my 89, I changed the thermostat, water intake, and the hoses along with a radiator flush and my temp gauge went to normal and has stayed there for 2 years now

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