Water Temp sender

Fawls · Feb 25, 2026

The latest update is I relocated the sender to the side of the block, took it for a test run and got the same readings, looks like my engine is running hot which is a surprise as I have all new thermostat (180 deg), water pump, radiator, hoses and header tank.I know it is not unheard of for a new thermostat to be faulty and I did buy an AliExpress water pump which might not be any good. The radiator is an aftermarket ally job and a lot larger than the original.I think the next step will be to find a mechanical thermostat that I can mount in the senders original location to double check the temp readings before I throw the parts cannon at it.Mounting this gauge mod may have saved my engine as I had no idea that I had a problem with the factory set up.

ttocs · Feb 25, 2026

check to see if the fan goes into high speed or only stays low speed.

Fawls · Feb 25, 2026

The fan was running at high speed, don't know about low speed though? funny thing is the fan wasn't running all of the time the temp gauge was showing really hot, just cut in and out without a change in temp on the gauge?

cobrajeff96 · Feb 26, 2026

It's normal for the fan to cycle as it reaches its activation temp (normally around 210*F triggered by the ECU coolant temp switch) and as it cools the engine it will eventually reach the low point deactivation (usually around 199*F). Seems the temp gauge doesn't reflect reality. Only way to be sure is to put a infrared gun into the mix.

07GtS197 · Feb 26, 2026

That’s pretty much the reason I suggested to read what the ecu sees. The sensor you have is probably reading faulty. If it were really running that hot the high speed fan would run continuously. And with a larger than stock radiator and a new (presumably working) thermostat, it’s unlikely a real overheating issue.

Fawls · Mar 7, 2026

Looks like its getting hot, I have a new Ford thermostat (190 deg) and ford water pump to try. First thing will be to test the old thermostat.

Fawls · Mar 7, 2026

I decided I should replace the stock sender as it wasn't showing the high temps and the fan was not staying on when it was hot, there seems to be two different styles of sender, are they the same? the Ford one has a different shaped "probe" bit to the one on my engine.

07GtS197 · Mar 8, 2026

There should only be one style. Do you have a picture or part number? I’m inclined to think the stock sensor is working correctly as the fan is cycling like normal. 250* is pretty damn hot.

Fawls · Mar 8, 2026

My one looks like this NTK one;

This is the Motorcraft one;

07GtS197 · Mar 8, 2026

The Motorcraft one looks more like a cylinder head temp sensor. Most likely the tip won’t affect anything but I’d try the NTK one just to be safe. They were probably the oem supplier anyway.

Fawls · Mar 9, 2026

Thanks, I have ordered the NTK one.

Fawls · Mar 24, 2026

I finally found some time to change the thermostat and water pump, unfortunately the thermostat I bought from Rock Auto (Motorcraft RT-1110) did not fit? I tested the one I took out against the original one (I'm not good at throwing things out fortunately). The original one (190 deg I think) took a lot longer to open and did not seem to open as far as the one I took out (180deg).

The water pump looked perfect but I replaced it anyway and put the original thermostat in and took it for a test drive. I stopped to check the mechanical gauge which was reading just over 190 deg, the dash gauge was reading about 2/3 hot.

It was a nice spot so I had a quick photo shoot of the car, when I got back in the dash gauge was rereading really high again so I thought I better get the car back home, I turned the heater on full and while driving the temp came back down a bit.

Temps when I got home was just over 200 deg on the mechanical and about 3/4 on the dash.

Thinking about it I might have only gotten hot because I have the mechanical gauge fitted replacing the temp sender for the fan, I will have to refit the sender and try again.

It is frustrating that the thermostat didn't fit, not sure where to look next for another one.

ttocs · Mar 24, 2026

I have a pushrod but I thought I had read that burping the modulars can be a royal PIA? If so I would have to wonder if there isn't still some air in there trapped throwing things off but otherwise the 190 was supposed to open later.

Fawls · Mar 24, 2026

I vacuum filled it so there should be no air pockets.
I'll refit the (new) stock sensor and try again.

cobrajeff96 · Mar 24, 2026

I could be wrong since all I've known personally is aluminum block/head mod motors since 96, but 200 after driving around is nothing. Even 220 should be quite fine as long as the pressure cap is rated at 16psi or greater which is just about all of them. It's only when the car hits 230 and ascending that you have to take action whether it's shutting the car off or something else critical.

I don't trust RockAuto for certain components, it's just too risk and I've seen other people get set back using them. Not to say I don't use them, in fact they hit a home run for me with some OEM brake components for my 18 Fusion. But for things like these I default to LMR or CJ Pony Parts. But definitely not American Muscle.....they suck ass.