Contour Enthusiasts Group Archives Forums General Troubleshooting Temp. gauge reads super low!?!

My 98 SE V-6 ATX's temp gauge has been unusually low since I had the local dealer flush the cooling system.

Where before the flush, normal operating temp was between the "O" and "R" in "NORMAL" it is now commonplace to see the needle hovering below the "N".

The car runs no differently, so I'm at a loss to assign blame. Do you think the thermostat might be broken, or did the dealer munge up the temp sensor? Or is my temp gauge just pessimistic?

The dealer used a slightly too-strong antifreeze mix.

You can check yours with a $2.99 - $5.99 tester from the local auto parts store. I recommend splurging on the bigger Prestone unit as opposed to the one with the little floating balls.

Of course, make sure the engine is cool when you open the pressure bottle.

With the mix strong enough to make the car run below the N, you might find that it never warms up in the wintertime.

Originally posted by 2redtours:

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The dealer used a slightly too-strong antifreeze mix.

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Actually that's the opposite.

Too much antifreeze versus water would cause the car to run hot. Water is a much better coolant (transfers heat better) than Anti-Freeze is.

Anti-freeze is used so the mixture doesn't Freeze. As an added bonus it contains an additive package to prevent corrosion. The new OAT antifreeze won't even leave deposits like the old green phosphate kind will as yet another bonus.

I normally run atleast 60% water to 40% anti-freeze. On my last car (a turbo) I ran 70% water & 2 bottles of water wetter to ~25-27% anti-freeze.

I have always used a 60-40 mix (antifreeze-H2O)Before my waterpump and thermostat change the temp gauge usually hovered at the 'NO' mark. It now sticks right before the 'N'.Both readings were within the 'normal' range and there is heat.
Personally I would rather have it low than high.

I think it has been mentioned before... BUT dont put to much stock in these guages, they are not calibrated, you dont know what the range is (but looking at the fan temps, the whole gague is only about 3-5 degrees celcius) so basically, if you REALLY want to know what your water temp is, get a mechanical water temp guage. Everything else is just a slightly educated guess.

on my 98.5 Mercury Mystique LS v-6 has the same problem after getting the coolants changed. I still have the stock waterpump and thermostat. Before the coolant change, my needle was usually at R in NORMAL, but now it's at N or slightly left of it. Nothing is wrong and heating and cooling is not affected or the operation of the engine.

my 97 tour sport V6 used to have this same thing 1-1/2 years ago, plus car warmed up real slowly in winter. Dealer tested and changed thermostat, then it warmed up much sooner but temp gauge still pointed low, next to the "N". Dealer then changed the water temp gauge sender unit and everything was fine. I was glad I had extended coverage.

Originally posted by DemonSVT:

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Originally posted by 2redtours:

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The dealer used a slightly too-strong antifreeze mix.

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Too much antifreeze versus water would cause the car to run hot. Water is a much better coolant (transfers heat better) than Anti-Freeze is.

Anti-freeze is used so the mixture doesn't Freeze. As an added bonus it contains an additive package to prevent corrosion.

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Sorry but I have to partially disagree. Ethylyne glycol both lowers the freeze point *and* raises the boiling point, as well as changing the heat transfer properties of the water. If you run straight antifreeze, the car will simply not warm up properly. I know this from experience in my old Ford Fiesta (not a Festiva, mind you, a real Fiesta, the first FWD Ford!) that had the thermostat go bad (stuck closed!). I did an on-the-road repair, and refilled the cooling system with straight antifreeze because I had no water available. The car ran cold until I partally drained and refilled the cooling system to get the mix right (note: it's much easier to get the mix right in a jug than in the car).

All moot, though. The best way to tell if the antifreeze mix is too weak or too strong is to test it with the correct tool and adjust from there.

Running too cold can accelerate engine wear, and decrease gas mileage too. As long as it's in the "normal" range, you should be fine. Keep an eye on it in the winter, though.