Kinda weird temperature readings

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Princess Valiant

Princess Valiant

A.K.A. Rainy Day Auto
Joined
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So I have a daily driven 68 dart with a 225 slant six. For as long as a can remember, normal temp is the gauge reads just above half way in the sweep in the middle of the normal range. The other day on Monday I took the radiator cap off to check the level because i was going to go on a trip (120 miles away)

The level was ok so I didn't add any. Since then the gauge is reading at the very low end of the normal range, almost into the cold side.

Even after driving the 120 miles and back, it's reading on the low end. Almost a week later and it's still reading on the low end from a dead cold, no matter what i do or how hot it is outside.

BTW: NON a/c car and runs and drives fine with no other known problems.
 
Rainy Day Auto said:
So I have a daily driven 68 dart with a 225 slant six. For as long as a can remember, normal temp is the gauge reads just above half way in the sweep in the middle of the normal range. The other day on Monday I took the radiator cap off to check the level because i was going to go on a trip (120 miles away)

The level was ok so I didn't add any. Since then the gauge is reading at the very low end of the normal range, almost into the cold side.

Even after driving the 120 miles and back, it's reading on the low end. Almost a week later and it's still reading on the low end from a dead cold, no matter what i do or how hot it is outside.

BTW: NON a/c car and runs and drives fine with no other known problems.
Click to expand...

Use an infra red temp gun at it and see what it says. Sounds like the sending unit may be bad.
 
Or high resistance at connector (dirty)
 
Make sure the cap is seated all the way.

If it is, check the seal to see if it tore.
 
Or you may possibly have a thermostat thats stuck open. Had that happen to me. You may want to mount a good aftermarket temp gage under the dash that has actual numbers on it.
 
Just squeeze the upper rad hose when it's hot, if you can collapse it it's not holding pressure and if you can hold your hand on it then it's probably under 140*F
 
The infrared temp guns are $15 on Amazon & work great. You can even use them for human thermometers.
 
I hate to tell you this, but your car is at the end of it's service life.
It's time to take it to the scrap yard and buy a new Toyota.
This is the only sensible solution to your problem.

Or you can follow the advice already given (which is excellent), fix it for under 20 bucks, and keep it on the road for another 51 years.
 
Dartnut said:
I hate to tell you this, but your car is at the end of it's service life.
It's time to take it to the scrap yard and buy a new Toyota.
This is the only sensible solution to your problem.

Or you can follow the advice already given (which is excellent), fix it for under 20 bucks, and keep it on the road for another 51 years.
Click to expand...
Go with option #2 keep it on the road another 51 years
 
Thermostat is the answer- stuck open.
Stuck open and the radiator is cooling faster than the engine can produce heat.
 
Just turn the radio up a little louder..............
 
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