Temperature Gauge Reads Extremely High (New 302)

[tx65coupe]

I am still thinking that maybe the gauge is reading high because these cars originally had cooler thermostats. I know my old 200 had a 160 or 165 stat in it before. I am wondering if going up 20 or 30 degrees actually makes the guage read that much higher.

If this is the case is there a different sending unit that I can use?

 

[2+2GT]

I am still thinking that maybe the gauge is reading high because these cars originally had cooler thermostats. I know my old 200 had a 160 or 165 stat in it before. I am wondering if going up 20 or 30 degrees actually makes the guage read that much higher.

If this is the case is there a different sending unit that I can use?

The factory used a 190°.

30° would certainly show up, even though these gauges were not very accurate.

The sending units were all supposed to be the same electrical value. I suppose you could go through a pile of them with a VOM and find one you'd like better, they do vary. Maybe yours has gone bad, that happens, too.

If the engine has been bored over at any time, it'll run hotter. 0.030" oversize requires a switch from 2-row radiator to 3-row radiator.

 

[hipo_p51]

if you have spent FAR to much, another 50 to 100 bucks for a good gauge and thermostat is a must.

 

[tx65coupe]

We discovered something interesting today. We took some values of resistance in boiling water and different temperatures with the sending unit. We then duplicated them with a POT and got the gauge to read somewhat normal. When the car is running it reads higher than this. Why would it read high with the car running? Interference from something?

I am wondering if it has anything to do with the aftermarket 100 amp alternator, or maybe the fact that the coil is mounted right next to the sending unit.

The thing about the aftermarket gauges is that there are already far too many wires that didn't come factory. I don't want any more of a rats nest. Thats part of the reason we don't have any aftermarket gauges except a tach.

Does anyone think it is the voltage regulator on the back of the cluster that is causing this?

 

[2nd Mustang]

The thing about the aftermarket gauges is that there are already far too many wires that didn't come factory. I don't want any more of a rats nest. Thats part of the reason we don't have any aftermarket gauges except a tach.

IMO, accurate gauges are really much more important than a tachometer in a street driven car. I look at my oil pressure, water temp and voltmeter more than I ever use the tachometer on the street.

As for rat's nest, use cable ties or those plastic coil ducting they sell at parts stores.

 

[D.Hearne]

I'm trying to figure out how getting an early start will increase radiator efficiency. Do you have a rigid fan? Clutch? Electric? Fan shroud?

Getting an early start on cooling would help only if you only drive short distances. After that, you're done. Try a 190° sometime. Oddly, it sometimes helps the engine run cooler. Something about the temperature differential of the coolant in the radiator vs. the ambient air. I'm not very good at thermodynamics, though.

Dual electric fans. The radiator really isn't big enough for my taste. Using a 195 T stat would only make the overheating worse, not better. Even on cold days, the operating temps get into the 180-190 range with the 160 t-stat. And it doesn't change, no matter how far it's driven. If you try towing too much of a load, then the temps gradually climb into the 240-250 range. Last time that was tried, I was towing my tandem axle 18 ft car trailer loaded with a 1967 Cub Cadet lawn tractor. In 25 miles the temps went from 180 to 250. 240 was reached about 2 miles from the house after getting off the highway and loosing the airflow at 55 mph.

 

[tx65coupe]

IMO, accurate gauges are really much more important than a tachometer in a street driven car. I look at my oil pressure, water temp and voltmeter more than I ever use the tachometer on the street.

As for rat's nest, use cable ties or those plastic coil ducting they sell at parts stores.

Thats just it though. My car has the dealer add on under dash AC, GT fog lights, some stereo stuff, a tach, and a couple other small wiring modifications.

I have used cable ties etc. There just isn't room under the dash for all the wiring. Also, I would have to run more wires through the firewall, which I really don't want to do.

I also don't have any place to mount a triple gauge set. I need some of the small 1.5 inch ones. Seconly, I don't like how any of the triple gauge sets look. I would want a set that matches my tach, which is vintage style.

Here is my tach.

Make Waves Instrument ILLUMINATED TACHOMETER 0-8000 RPM 2 : JC Whitney: Auto Parts & Accessories

Does anyone know of a mini triple gauge set that matches the style of my tach and is volts, oil, temp?

 

[tx65coupe]

I would really prefer to just get my stock gauge to read somewhat normal, so I can tell if/when its getting too hot.

 

[D.Hearne]

Thats just it though. My car has the dealer add on under dash AC, GT fog lights, some stereo stuff, a tach, and a couple other small wiring modifications.

I have used cable ties etc. There just isn't room under the dash for all the wiring. Also, I would have to run more wires through the firewall, which I really don't want to do.

I also don't have any place to mount a triple gauge set. I need some of the small 1.5 inch ones. Seconly, I don't like how any of the triple gauge sets look. I would want a set that matches my tach, which is vintage style.

Here is my tach.

Make Waves Instrument ILLUMINATED TACHOMETER 0-8000 RPM 2 : JC Whitney: Auto Parts & Accessories

Does anyone know of a mini triple gauge set that matches the style of my tach and is volts, oil, temp?

You don't have to mount it permanently, only hook it up for as long as it takes to solve your worries about the factory gauge. Cheap insurance if you ask me. Plumb both together using a "T" fitting so they're both reading off the same point in the coolant flow. Then remove and restore it all back the way you want when you're done

 

[2nd Mustang]

You don't have to mount it permanently, only hook it up for as long as it takes to solve your worries about the factory gauge. Cheap insurance if you ask me. Plumb both together using a "T" fitting so they're both reading off the same point in the coolant flow. Then remove and restore it all back the way you want when you're done

I have a vacuum gauge mounted inside of my engine compartment. I had it mounted under the dash, but for some reason, the plastic line always got too brittle inside of the car rather than in the engine bay. Figure that one out.

 

[D.Hearne]

I have a vacuum gauge mounted inside of my engine compartment. I had it mounted under the dash, but for some reason, the plastic line always got too brittle inside of the car rather than in the engine bay. Figure that one out.

And this has to do with what ?

 

[2nd Mustang]

And this has to do with what ?

Just saying that if space is a concern, mounting the gauges in the engine compartment is another alternative using a tee fitting as suggested to work along with either stock gauges or idiot lights.

 

[2+2GT]

We discovered something interesting today. We took some values of resistance in boiling water and different temperatures with the sending unit. We then duplicated them with a POT and got the gauge to read somewhat normal. When the car is running it reads higher than this. Why would it read high with the car running? Interference from something?

Well, the battery provides 12V, while the alternator should be producing about 14V. Check the CVR on the back of the instrument panel.

 

[tx65coupe]

How do you check the instrument cluster voltage regulator?

It is new.

Also, We have an adjustable DC power supply and increased from 12 volts to 14 and the gauges didn't really rean any different. It they did it was half a needle width to a needle width higher.

Is the electronic cluster regulator from NPD the way to go?

I may put an aftermarket guage under the hood temporarily.