Possible Temp Gauge Issue?

[ghjedi]

Hello,

I took my Challenger out for a run the other day and noticed that the temp started climbing on me.  I was winding it up a bit around town and noticed that my gauge started crossing 190F (where it usually stays after warming up) and ultimately went above 230.  The last time it did this, my car overheated and the issue was traced to lost fluid from a old, leaking heater hose.  I promptly drove home and didn't notice any signs of overheating with the car still on and idling.

I have a digital heat sensor and I checked the temp at both radiator hoses and value cover surfaces-- all came back with temps less than 200, which is what I'd expect for a warmed up car at idle on a warm day.

I have an after-market gauge installed with actual temp numbers on it vs. a hot/cold range indicator and it has been pretty reliable.  I am thinking that the temperature sending unit may be going bad or possibly the gauge itself, but I'd appreciate other perspectives.  I don't think there are any overheating issues, as my car was running fine and I checked the temperature with an independent digital heat sensor.

Thoughts?

[Giveitawack]

What about the fuel and oil gauge? Have they shown too high values? In that case it might be the 5 v voltage regulator for the gauges.

[MEK-Dangerfield]

First question, do you have a stock Mopar radiator or aftermarket one? What type of fan?

I'm just guessing if you hit 230* for real, you might somehow notice it. Pinging perhaps, but maybe a smell or you can hear boiling to idicate what's going on. Since you didn't, I would suspect the sending unit first. Did you check the coolant level just to be sure?

Oh, and another question....When you got back home, was it still reading 230*?

[ghjedi]

First question, do you have a stock Mopar radiator or aftermarket one? What type of fan?

I'm just guessing if you hit 230* for real, you might somehow notice it. Pinging perhaps, but maybe a smell or you can hear boiling to idicate what's going on. Since you didn't, I would suspect the sending unit first. Did you check the coolant level just to be sure?

Oh, and another question....When you got back home, was it still reading 230*?

Hi, I have an after market radiator with a mechanical fan.   I don't know exactly what type of radiator, as it was in the car when I purchased it.  It looks to be new and very clean inside with no rust or corrosion.  I did not check the fluid level afterwards, but I will later tonight (just to be safe).  I can say that the car didn't display any signs of overheating: no bubbling, no coolant spills, no steam, no rough running, etc. 

The temp gauge did continue to register over 230 after I got home from my 20 or so minute drive.

I am suspecting the sending unit too.

[ghjedi]

What about the fuel and oil gauge? Have they shown too high values? In that case it might be the 5 v voltage regulator for the gauges.

Hello, the fuel gauge reads fine and my oil pressure read fine too. I should mention that I have a 3-pack after market set of gauges mounted under the dash for oil pressure, temperature, and voltage. I'll take a photo of it to help clarify.

All of my stock gauges work, except for the original temp gauge, which is disconnected. 

[brads70]

I've always used mechanical gauges in all my cars. Someone long ago told me to steer away from electronic gauges. It's always worked for me? Really I have no experiance with that type of gauge, but me.... I'd always buy the best quality gauges I could get, as really they are not a big investment but engines usually are?

[ghjedi]

I've always used mechanical gauges in all my cars. Someone long ago told me to steer away from electronic gauges. It's always worked for me? Really I have no experiance with that type of gauge, but me.... I'd always buy the best quality gauges I could get, as really they are not a big investment but engines usually are?

Definitely some sound advice!   I certainly don't want to get in the habit of ignoring my temp gauge because of "false negative" readings.

Any advice on quality after-market gauges to mount below the dash?

[brads70]

Definitely some sound advice!   I certainly don't want to get in the habit of ignoring my temp gauge because of "false negative" readings.

Any advice on quality after-market gauges to mount below the dash?

I've always used Autometer stuff?

Here's mine. I had to make a bracket to clea rthe vent handles. I have 3 gauges on there now, I added a fuel air ratio gauge.

[ghjedi]

Just a quick update on this thread: I checked the the coolant level and it was full.

After taking a closer look at my gauges, the maker is Equus (photo below).  I'm not sure how good this one is, but I'm thinking about upgrading to something like this: http://www.summitracing.com/parts/ATM-2398/

[ShelbyDogg]

Had some bad guages before, Including the cheap sets from Autometer called Autogauge.   Try another gauge first like you planned to. 

Can't run another wire to get the original sender hooked up to the original gauge too?

[ghjedi]

Had some bad guages before, Including the cheap sets from Autometer called Autogauge.   Try another gauge first like you planned to. 

Can't run another wire to get the original sender hooked up to the original gauge too?

That's a good idea, but unfortunately, I don't have the original sender to connect to.  The prior owner removed it. 

I took the car out Sunday and the gauge was not acting up.  It seems to be a sporadic issue now.