"please Help" Temp Problem

HOGNATION

Active User
Jan 28, 2016
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I have a 1991 GT and have two problems.
1. I think my temperature guage is not working. Its show its running at about 220 I know that in the high end of normal but don't think it should run that hot, maybe 200 at most. I've replace the sensor to the guage and bought a new radiator cap w/ a temperature guage built in but its show about 135 at most.

2. I can't keep coolant in my reservoir and at the same time I don't smell any coolant or see any leaks when I park the car.
 
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The stock gauges are notoriously inaccurate. Go down to Wal-Mart and buy a candy thermometer, remove the radiator cap and stick it in the coolant. Watch for lots of bubbles in the coolant; that is an indicator of a blown head gasket.

Also check the oil to make sure that it doesn't look milky; if it does, that's a sign that coolant is leaking into the oil. That usually means a blown head gasket.
 
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I've had the cap off with it running but didn't see any bubbles while running. Are you saying having a candy thermometer in it will make a difference? Also checked the oil and it looks good. I'm thinking about buying a mechanical guage and hook it up to see what it reads. I think your correct in saying that guage is probably gone bad. Plus I think the car would have overheated by now because my drive to work is 45 minutes to work. Thanks for the help.
 
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I've had the cap off with it running but didn't see any bubbles while running. Are you saying having a candy thermometer in it will make a difference? Also checked the oil and it looks good. I'm thinking about buying a mechanical guage and hook it up to see what it reads. I think your correct in saying that guage is probably gone bad. Plus I think the car would have overheated by now because my drive to work is 45 minutes to work. Thanks for the help.

The candy thermometer is a cheap and easy tool to check and see what is really happening with a engine coolant temp. Wal-Mart has them for less that $8, and the fancy ones with a long metal probe are less than $15

A temp gauge that increases temp as electrical load is increased ( turn on the lights, heater fan, etc.) is a sign of a bad engine to body ground.

The secondary power ground is between the back of the intake manifold and the driver's side firewall. It is often missing or loose. It supplies ground for the alternator, A/C compressor clutch and other electrical accessories such as the gauges.
 
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All have to check that then. Currently I don't see any change putting on the lights/fog lights or even with heater running and heater is working great. thank you for all the input to my problems.
 
With a 45 minute drive daily, buy an autometer mechanical gauge and install it where you can see it at all times.
The peace of mind is worth it. Get a full sweep gauge.
I'm a fan of aftermarket coolant gauges in general, even more being that far from home.
 
With a 45 minute drive daily, buy an autometer mechanical gauge and install it where you can see it at all times.
The peace of mind is worth it. Get a full sweep gauge.
I'm a fan of aftermarket coolant gauges in general, even more being that far from home.

I'm going to do that just for the reason you mentioned "PEACE OF MIND". You like the autometer ever experience an problems with them. I like to find a new dash bezel that looks stock to the 91 dash and install autometer guages.
 
I'm going to do that just for the reason you mentioned "PEACE OF MIND". You like the autometer ever experience an problems with them. I like to find a new dash bezel that looks stock to the 91 dash and install autometer guages.
Not sure I've ever heard of anyone with any issues with mechanical gauges (which I prefer), I just don't like senders on electrical gauges. Not to say electrical isn't fine, I just trust mechanical more.

Florida5.0 and others make full dash bezels. Some guys use and like them, but I'm more into the factory look. Besides it takes hundreds of dollars of gauges to fill them up.
I use the autometer dash vent pod with openings at the ends where maintain some heat and AC.
I like to monitor oil and water.

Almost identical to this, other than I have phantom gauges.
https://replayman.wordpress.com/2009/12/27/proper-mustang-vent-pod/
 
The stock gauges are slightly better than idiot lights. Install a good set of autometer gauges. I prefer electrical only becuase I dpn't want to run hard oil or coolant lines inside my car.
 

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Not sure I've ever heard of anyone with any issues with mechanical gauges (which I prefer), I just don't like senders on electrical gauges. Not to say electrical isn't fine, I just trust mechanical more.

Florida5.0 and others make full dash bezels. Some guys use and like them, but I'm more into the factory look. Besides it takes hundreds of dollars of gauges to fill them up.
I use the autometer dash vent pod with openings at the ends where maintain some heat and AC.
I like to monitor oil and water.

Almost identical to this, other than I have phantom gauges.
https://replayman.wordpress.com/2009/12/27/proper-mustang-vent-pod/

The stock gauges are slightly better than idiot lights. Install a good set of autometer gauges. I prefer electrical only becuase I dpn't want to run hard oil or coolant lines inside my car.

Has anyone ever seen aftermarket electrical oil and temp gauges that are rectangular and read sideways?
cf-15.jpg


I have a 1 1/4" blank panel below the radio that would be perfect fit for something like this...

Maybe I need to get busy and build a digital version of it...
 

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Has anyone ever seen aftermarket electrical oil and temp gauges that are rectangular and read sideways?
cf-15.jpg


I have a 1 1/4" blank panel below the radio that would be perfect fit for something like this...

Maybe I need to get busy and build a digital version of it...


Other than older stock gauges no, not come across aftermarket electric gauges like that, Digiital ones yes...
 
The stock gauges are slightly better than idiot lights. Install a good set of autometer gauges. I prefer electrical only becuase I dpn't want to run hard oil or coolant lines inside my car.

If you change out the plastic oil line for the copper it's not so bad.
The water temp guage doesn't actually run coolant in the line. The tip of the probe gets heated, expands a liquid in the coolant line and that's how you get the temp on the gauge.

The oil line could be iffy, but the coolant line is nothing to worry about. I also got a coolant line caught in my steering shaft back in the day, tore it all up, no collateral damage.
 
Well the problem was the guage in the dash. I put a mechanical guage on it and let it idle for about 30 minutes and it didn't get over 190. Thanks for all the help and input.
 
I always recommend an autometer water temp and oil pressure gauge. Especially if it's a daily and subject to heavy city traffic. Money well spent.
 
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was at a car show over the weekend and saw some 50's and 60's cars had square analog gauges

upload_2016-2-1_19-22-10.jpeg
I think those square things with numbers are fuzzy dice not gauges. Highly doubt they are accurate. Numbers probably change when you go over bumps.
So they would be equivalent to our stock gauges.