temp gauge pegged all the way hot

[yellow98cobra]

Just got my car back from having the push rods replaced and the temparture sending unit was found to be broken and he replaced it and now the gauge reads hot. My mechanic checked the tempature and said it was running at 165. He said that this is common and he suggested puting a resistior on the line to make it read normal. Has any one done this? What kind of resistor would I use?
Thank you, Eric

[simplyconnected]

Rather than circumvent the root cause, why not replace your defective parts? All the 'classic car' vendors carry sending units.

[jopizz]

If the sending unit was already replaced it's possible your gauge needs to be adjusted. There's a procedure in the Technical Resource Library on how to do it.

John

[Anders]

These needles are V E R Y fragile. If anyone have opend the guage it´s nearly enough to breath close to the fuel / temp to make those bend. Does it move from Cold to Warm or from "Mid" to Warm? If if goes from Mid to Warm, I would suggest that you opend the bezel with the glass and just pull a little to set it where you want it, as the car seems to run in the right range anyway. But use something small like a wooden tooth pick to work with. No pliers or other metal tools. That will most probably destroy more than solve.

[Dakota Boy]

Gauge needle high and low settings are done by moving the little star wheels on the back of the unit. I've adjusted my fuel gauge, but have not had to mess with my temp gauge. I wouldnt recommend tweaking on the needles themselves.

Perhaps the newly-replaced sending unit is not the right one?

Seems odd that your gauge was perfectly fine before the part was swapped.

[yellow98cobra]

Not sure if it was ever right it never seemed to move at all. Always on the low side. My mechanic said it was broken and that is why he put a new one on. the invoice list STD TS4 temperature switch as the one he installed dont know if that is the correct one it is most likely one from NAPA auto parts.

[jopizz]

The TS4 is the correct sender. It makes more sense now that you said it never worked right. If the mechanic is correct with his temperature readings it could only be the gauge or the constant voltage regulator. If your gas gauge is working correctly I would suspect the temp gauge needs adjusting.

John

[yellow98cobra]

( I did a search I dont want to remove the whole insturment panel) From reading other posts on removing gauges I can remove just the Fuel, temperature gauge by pulling of the bezel and removing three to four small screws that hold them in?????

The gas gauge doesnt work nor do the insturment lights. I do have turn signal lights and the generator light on the panel that work and all of the other lights on the car work.

[YellowRose]

temp gauge pegged all the way hot

Hi Eric, yes you have that right. First though, I am a bit confused if you have any reading at all on your gauge. I gather that your gauge was reading "low" before you took it in for service. Could "low" mean not reading at all? Secondly, I see you said your gas gauge does not work. If that is the case and you are not getting any reading at all on the Temp gauge, or it now goes all the way to hot, you could have a blown Constant Voltage Regulator (CVR) unit. That CVR unit provides an input of 12v and an output of a oscillating 0-6v going to the gauges. IF the CVR unit has blown, 12V could have gone to the 6V gauges and burnt the wiring to them, taking them out. The CVR unit is either located on the back of the instrument panel or on a metal support post behind the instrument panel. If it is on the instrument panel you will probably have to pull the panel to get to it to check it. If you look in the hole and see the CVR unit grounded to a metal dash support post, you may have to pull the speedometer to get to it to test it.

You need to put a voltage checker on the input side and check for 12V. Then check the output side going to the gauge to see if you have 12V or an oscillating 6v. If you have 12V, your CVR is shot. If you have 6V, then you might be able to make the adjustments on the back of the gauge to make them read correctly again. Those instructions are on the TRL which you can always find the link to in my Signature element below. You can get OEM type CVR units from most any of our Tbird parts houses if it is shot. Or a solid state one for about $50, like I have. After two OEM types went out on me, I opted for the new solid state one and have not had a problem since. Information is in the TRL. Make sure if you get an OEM type that it is not made in China. I am told they are sometimes or often defective.

If you do have 6v going to the gauge, make sure there is a connection coming off the fuel part of the gauge going to the input of the Temperature gauge. That is how the Temp gauge gets its power.

I will post a couple of pix, one of what the CVR unit looks like mounted to the back of the instrument if that is where it is on your Tbird. The other with a mounting stub on it to mount it to a metal dash support.

This is from the Technical Resource Library (TRL) in the section on Replacing the Dash.

6. Pull off the bezels surrounding the fuel/temperature gauge. Unscrew the instruments, disconnect the lamps and wiring and remove.

Now, once you have the fuel/temp gauge out, I would suggest that you take pictures of the wiring on the back of the gauge. You will want to know how to hook it back up correctly later on. You also might want to tag the wires before you take them off. That way you will know which was plugged into the Fuel part of the gauge and which was plugged into the Temp part of the gauge.

If your gauge is bad, the Bird Nest can repair them, or you might be able to get a replacement from Carl Heller ~ partsetal here on the Forum. I know one of our members just did. I hope this helps, but please read through the information regarding the gauges and the CVR unit in the TRL.

If you look close at the OEM CVR picture you will see that one side is marked IGN, telling you that is the 12V link from the Ignition switch. The other side would be the 6V output.

As for your dash lights not working, you could have a blown fuse or connection problem on your headlight switch. Or the rheostat could be corroded. If you turn the headlight switch left or right, the lights should dim or light up. Or the light bulbs are out, or not connected.

[yellow98cobra]

I always go through the TRL and do a search on the forum before I ask questions.

yes "low" could mean not reading at all. as I am not mechanicial inclined I am scared to take that a part. I take things apart but rarely get them back together right or I break more things. What I thought would be fun to tinker with is now freaking me out so much that I am thinking maybe I should just get rid of the car it is more than I will be able to do.

[tbird430]

Well, if your scared to do that then I don't see why selling the WHOLE car off would help anything.

This is a minor fix in my opinion, and I'm just a shade tree mechanic.

When you buy a replacement car there will just be another small problem like this, are you just going to sell it off too??

Heck, print out our TRL sheet & hire your mechanic to do this for you....

Good luck on whichever you choose,
Jon in TX.

[jopizz]

As much as I love squarebirds they can be a nightmare to work on even for experienced mechanics. Compare the wiring with an early 60's Chevy and you'd be amazed how few wires you need when it's designed correctly. Combine that with the confined spaces and you'll be spouting obscenities that you never knew existed. All that being said it's not like it's your everyday car. If you break something you have plenty of time to step back, read up on the problem and try to fix it. We were all novices at one time.

John

[yellow98cobra]

Today

I went for a drive around town then hoped on the freeway for a mile. The temp gauge only went to the right side of the T\EMP.

I picked up a laser temp reader at Harbor Frieght for $40. I read the temp at expansion tank It read 177 the radiator read 144 -150 The expansion tank did discharge some fluid when I was doing the readings. My mechanic said it might do this until it settles at a level it likes?

[YellowRose]

temp gauge pegged all the way hot

Hi Eric, the fact that your Temp gauge is indicating a reading just to the right of the letter T seems to indicate that your Temp gauge is getting voltage to it and is working. If you let it sit and idle for awhile, does that temperature reading rise on the needle? If so, I would say you have a working Temperature gauge. Regarding the expansion tank. The function of it is to let heated water to "expand" into it, rather than boil over, as I understand it. I recall reading recently that someone said that the expansion tank should only be about 1/3 full of coolant. Not filled up to the brim, or 3/4, but about 1/3 of the way full. This allows the hot water to rise some more without spilling out your coolant through the drain tube that should be attached to it.

You said that your Fuel gauge was not working or indicating anything I gather. Since your Temp gauge appears to be working, your Fuel gauge should be also indicating something. As I recall, the lead from the CVR unit goes from the output side to the input of the Fuel gauge first (Someone correct me if I am wrong), and then to the Temp part of the gauge. The fact that your fuel gauge is not indicating could be caused by other things than the CVR unit. Lets assume that your CVR unit is putting out an oscillating 0-6V to the Fuel gauge and the Temp gauge. But your fuel gauge is not indicating anything.

Where is the needle sitting on the Fuel gauge. On the letter E or the letter F? Or anywhere in between? The problem might not be with your CVR unit at all, if your Temp gauge is indicating correctly now, but either in an adjustment made to the back of the Fuel gauge, or your sending unit in the tank is bad, or you do not have a good ground on it. Those are the areas I would check into before I try to pull and check the CVR unit.