So, my IDI project truck has been doing an odd thing. Every now and again the temp gauge will start pulsing, and then it pegs, and then it falls back to normal a few seconds later. There doesn't seem to be any rhyme or reason to it, and it'll do it before the engines had time to get up to temp.

My suspicion is that it's either the sensor or a short, but either way I have no way of knowing if it's reading right. Either way I stopped driving it around just in case.

The rad is only a few months old, and the heater works so fluid is flowing, and the cap holds pressure. No coolant loss either. If it is overheating it's either the water pump or the stat.

In order to know for sure I've got a set of gauges, oil/water/volts that I mean to install but I don't know where to get coolant temp from.

The lazy in me says to just splice into a heater line near the pump with a t-fitting, but I'm sure there's a better place to connect it.

Anybody know?

Thanks!

 

I've been looking at it, and there's two temp sensor ports on the drivers side head, but both seem to be occupied. There looks like there is a large port on top of the water pump. Tomorrow I'm going to unscrew it, it looks like one of the fitting might be the right size.

Or should I replace one of the existing temp sensors?

 

Deleted. Gone.

 

We just installed a similar set of gauges in a 6.9 swap into a 79 f-150. The adapter that came with is went right into the above mentioned pipe tapped hole at the back of the drivers side head. To work correctly, they MOST have a good flow of coolant around the sensor. They also say to NOT use any sealant (tape or putty) as they can interfere with correct operation. For the oil, a "tee" under the sender worked fine.

 

Sorry for the typos. They "MUST" have a good flow of coolant.

 

This thread has some good info and GREAT pics:

https://www.ford-trucks.com/forums/1...-location.html

Mike

 

link fix;
https://www.ford-trucks.com/forums/1...-location.html

 

Finally got the gauges installed

Still need to do the oil pressure line, but the volt gauge and the temp gauge seem to work. I used warning light port because the rear port looked too awkward an spot to get to with the engine in the truck.

Haven't really driven it around much yet, but I'll post up whether it turned out to be electrical or not.

Thanks for help!

 

Drove around for a few hours today, no temp spikes, and the factory gauge seems to read a little low, when it isn't jittering around.d

 

Yeah, the OE gauge is pretty much worthless. Most put some sort of aftermarket gauge in, and the port you used is a pretty popular location. I used the same on mine.

Your temp looks about right, if a little low. I'm guessing that last pic is after you shut down, though, since your voltmeter is barely reading over 12v (should be closer to 14 when the engine is running). My temp gauge reads 190-200 once up to temp. It WAS right around 205 not all that long ago, but a new thermostat took care of that!

Mike