1993 Thunderbird SC odd temp issues.

Massoketsc

Registered User
So I was curious, I had purchased my SC about a month ago or so and it had some overheating issues.. tracked it to a bad IRCM. I replaced the IRCM and the bad coolant temp sensor today, and the fans finally start to turn on by themselves (they weren't before without the working IRCM), however the car waits until it gets to approx. 215 degrees before the fan turns on, where-as the car is already 3/4 the way to the red (never goes to the red, it drops down after fan kicks in).

Is there anyone who could possibly tell me if they know what is causing it to pass the normal temperature stage? I am not used to a car that has correctly working components that has such dramatic gauge readings.

I replaced the thermostat, new coolant temp sensor, IRCM, new radiator hoses.. did pressure tests on radiator and radiator cap and all are well.. could it maybe be the other coolant temp sensor that controls the gauge? maybe it's not reading correctly?

I am stumped but I am nickel and diming myself trying to figure it all out :)


Also.. anyone in the Seattle, WA area that has a set of the 16" SC wheels for sale in good condition? (random, but I need them.. so eh) :)

Thanks for reading.
 
One the thing to check is that the push-on connector at the temp sender on the thermostat housing is tight and not corroded.

Pull it off, check/clean the connector & post, apply a touch of dielectric grease, squeeze it down in size a bit with some pliers and push it back on.

When you replaced the sender (both?), did you use any teflon or sealer on the threads?

Also confirm the overflow tube is clear going to the tank.

You might want to use a temp gun to check for hot spots, flow etc.

Run the car and see how the gauge inside reads/reacts after this process.
 
I hate to be a doomsdayer, but....

One the thing to check is that the push-on connector at the temp sender on the thermostat housing is tight and not corroded.

Pull it off, check/clean the connector & post, apply a touch of dielectric grease, squeeze it down in size a bit with some pliers and push it back on.

When you replaced the sender (both?), did you use any teflon or sealer on the threads?

Also confirm the overflow tube is clear going to the tank.

You might want to use a temp gun to check for hot spots, flow etc.

Run the car and see how the gauge inside reads/reacts after this process.


IMHO, you should start searching for a new radiator. It sound to me like, although not totally plugged, your radiator might be somewhat plugged. Take off the cap (when cool) and use a flashlight to check out the cooling core and see if there is alot of gunk built up in there. If more than a few are partially or totally plugged, either get your radiator serviced, or just replace it with a new aluminum RadiatorExpress unit. I think they start at $135.00 for a direct bolt-in replacement. From what I have read on here, they are reliable as well. Cheap insurance if you ask me!!
 
re

The person who owned the car before me either really neglected the car, or it had just been sitting for too long that a bunch of sensors went bad, but I had to replace the IRCM, Throttle Position Sensor, Coolant temp sensor (1 so far, have not replaced the sending unit part associated with gauge), had radiator inspected (seems to be good for now,.. but i might take a 2nd opinion).. engine block is good, no headgasket issues..

The reason I do not think it is the radiator is, before I had the IRCM replaced, I had the fan(low speed) runnning at all times when the ignition was on, and the temp gauge ALWAYS stayed right in the middle when warmed up.. only time it went up the slightest bit was under load going up hills. I think it is the fan issue, not turning on when it is supposed to, I just wish I knew which part to start with..

This is the 2nd SC that I have owned, the 1st one had Lots more problems than this one thankfully, and I am hoping soon that I can get all the small issues taken care of and start working on the larger replacements (tires etc)

Also.. does anyone know why a seatbelt light would stay lit in the dash if the belts are all connected? The drivers side automatic seatbelt does not work, it is stuck in the position like when you are driving (thankfully) I am thinking its a bad motor, but could that make the light stay on? or is it some kind of sensor that is stuck/needs replacing?


Anyhow, thanks for reading once again ;) trying to figure all of this out piece by piece.
 
The reason I do not think it is the radiator is said:
All the more reason to think the radiator is your issue. If you had the fan running ALL the time your ignition was on, that would make it run cooler than normal, and the needle would probably be less than half way across the gauge. I say replace the radiator with a new one, like I said before, cheap insurance. Think about it, your car is around 20 years old and probably still running the original radiator.

Just my .02 cents
 
re

it seems that it was a whole mess of a bunch of things, probably all stemming from (possibly) a bad radiator or something.. as the thermostat was stuck open, the IRCM was toast, needed new coolant temp sensor, etc etc.. it also was throwing a code that the TPS was bad, or too low voltage (had it replaced as well, but nothing to do with radiator) I just think that it sat too long, i am going to have the radiator flushed and see if that helps at all, and then think about replacing it if it does not change. I will be replacing tons of things on this car in the future, just trying to keep up with finances in the mean-time. Locally a radiator for my car starts at around $230 for just the radiator for the SC of my year, if it were an LX it would be $100 less! but what fun are the LX's anyhow in comparison :p Besides finding parts cheaper..

I also was curious.. the person that had this car before me had the LX wheels/tires on here.. are those okay for performance if I buy new tires for the wheels for this car? or should I look into getting the original SC wheels from somewhere and buying the tires for those? I was just seeing if the half an inch width difference or so would make a huge difference for performance if I were to buy some decent tires for them.. Thanks ;)
 
it seems that it was a whole mess of a bunch of things, probably all stemming from (possibly) a bad radiator or something.. as the thermostat was stuck open, the IRCM was toast, needed new coolant temp sensor, etc etc.. it also was throwing a code that the TPS was bad, or too low voltage (had it replaced as well, but nothing to do with radiator) I just think that it sat too long, i am going to have the radiator flushed and see if that helps at all, and then think about replacing it if it does not change. I will be replacing tons of things on this car in the future, just trying to keep up with finances in the mean-time. Locally a radiator for my car starts at around $230 for just the radiator for the SC of my year, if it were an LX it would be $100 less! but what fun are the LX's anyhow in comparison :p Besides finding parts cheaper..

I also was curious.. the person that had this car before me had the LX wheels/tires on here.. are those okay for performance if I buy new tires for the wheels for this car? or should I look into getting the original SC wheels from somewhere and buying the tires for those? I was just seeing if the half an inch width difference or so would make a huge difference for performance if I were to buy some decent tires for them.. Thanks ;)

Go to www.radiatorexpress.com for your radiator if you need one. The price range from $169.00 to $189.00 SHIPPED!! Can't beat that and they have a good reputation here on this board. I am about to purchase one myself.
 
215 degrees is apprx correct for you fan to be kicking in. If you gauge is showing almost to red when the actual coolant temp is 215 then the gauge is reading wrong. 215 is around half way, with 230 being on the high side of the words norm or normal.
 
Yeah...your fan controls are working properly - like others have said, the low speed doesn't kick on until 220°F.

If you're stop and go in traffic (especially with AC on) when the temperature rises, but stays steady on the highway, I wouldn't worry about it. If the fan kicks on and drops the temperature easily, then you're radiator must be removing the heat well enough (once airflow through it is high enough).

Like KMT suggested, you can clean/adjust your temp sender and see if that helps the gauge readout, or even replace it, but it only feeds the gauge. The computer uses the two-pin ECT sensor for turning on the fan, adjusting timing, etc.

Make sure your little air dam is there too...it helps while you're moving.
 
215 degrees is apprx correct for you fan to be kicking in. If you gauge is showing almost to red when the actual coolant temp is 215 then the gauge is reading wrong. 215 is around half way, with 230 being on the high side of the words norm or normal.

Not that the factory gauge is that accurate, but based on experience with different thermostats and fan turn-on temps in the same cars, I would say that 197°F is in the middle of "norm" (the factory t-stat opening temp), 180°F is about halfway between the blue and the "N", and 220°F is somewhere between the "M" and the red.
 
Not that the factory gauge is that accurate, but based on experience with different thermostats and fan turn-on temps in the same cars, I would say that 197°F is in the middle of "norm" (the factory t-stat opening temp), 180°F is about halfway between the blue and the "N", and 220°F is somewhere between the "M" and the red.

Good info - going in the notes, thanks.

But Doctor, where is "Oh, s*Ht!!"...supposed to be? Before, on or after the red stripe :rolleyes:
 
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Good info - going in the notes, thanks.

But Doctor, where is "Oh, s*Ht!!"...supposed to be? Before, on or after the red stripe :rolleyes:

Fortunately, I've never seen it that high. :D Except when trying using the climate control temp switch to get a gauge reading. :rolleyes: In that case, it's either blue or red!

Not to get off topic, but I ended up putting the proper sending unit in the factory location for the climate control temperature switch (over in the heater core hose). Turns out, even there, the gauge reads about the same as the stock location (based on my autometer gauge sensing in the stock location).
 
Old thread I know.

Like KMT suggested, you can clean/adjust your temp sender and see if that helps the gauge readout, or even replace it, but it only feeds the gauge. The computer uses the two-pin ECT sensor for turning on the fan, adjusting timing, etc.

Where is the ECT sensor?
 
Mine has never been that high 'cept when I was testing out my OBD1 scanner. I monitored engine temp to see when the fan cut in, but those temps are correct.
 
ECT is for the computer and the temperature switch is for the gauge.
 

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