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post #1 of 14 (permalink) Old 02-07-2004, 02:40 PM Thread Starter
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Low Coolant Idiot Light Question

Anyone know what exactly the low coolant light measures within the cooling system? Its been coming on during extremely cold nights but when i check the levels, the radiator is filled as well as the overflow, so im kinda stumped. If anyone knows what exactly triggers that light it would be etremely helpful.

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post #2 of 14 (permalink) Old 02-07-2004, 03:40 PM
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Same thing happens to me...wonder what it is?
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post #3 of 14 (permalink) Old 02-07-2004, 03:57 PM
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ditto.itgoes away after you drive a little bit.it's gotten to negatives here, but anything under about 10 it starts doing it

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post #4 of 14 (permalink) Old 02-07-2004, 05:27 PM
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Well, on mine, the sensor is a dangly pair of electrical contacts in the overflow tank, so I'm assuming that it's just measuring resistance between the two exposed prongs, which are about an inch or so apart. Low resistance = prongs immersed in coolant, so all is well. High resistance = prongs uncovered, and the little dash light goes on. Since it seems to have something to do with the weather, maybe the extreme cold is goofing with how the sensor measures that resistance...
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post #5 of 14 (permalink) Old 02-07-2004, 09:55 PM
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the sensor in your reserve tank may be dirty.
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post #6 of 14 (permalink) Old 02-12-2004, 11:07 AM
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Originally posted by nene
the sensor in your reserve tank may be dirty.
I agree...it's happened on my car before. I performed a coolant flush, cleaned the sensor, and haven't had the problem return.
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post #7 of 14 (permalink) Old 02-12-2004, 11:15 AM
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I think if you look closely at the "dangly" things you will see a float in the middle of them. I'm pretty sure it is just a switch. If the float goes down so far, it closes the switch and triggers the light. As the fluid heats up, the level rises slightly and opens the switch.

At least that is the way the 80's mustang one works. I haven't looked at the T'Bird though, so I may be off base. I doubt that it's measureing resistance through the coolant though.

Just my .02.

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post #8 of 14 (permalink) Old 06-22-2004, 08:42 PM
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Hi all.......I've been having trouble with my radiator low light also. I was on my way to church this past Sunday which is a 15 minute drive from my home and the light came on. Since then it's not went off. The coolant level is fine in radiator and reservoir. Just in hopes of getting it to go off my husband replaced the lower radiator hose cause it was feeling quite "spongy", replaced the thermostat from a 192 to a 197. Was told the 197 was stock t-stat at AutoZone so we got that one. We also replaced the temperature sending unit sensor. With all this done today the low light is still on. Any idea will be *greatly appreciated*!! BTW, no flush was done, but husband did put new antifreeze in it today as well. If you haven't noticed by now.........my husband is not a Ford man, but he's certainly trying his best at taking care of my baby bird and has been very greatful for all he's learned from all of you helpful people here. You are all incredible and we thank you very much for sharing your incredible knowledge!

I would also like to mention that about 2 wks ago I was sitting with my car in park with engine running and all of a sudden the engine starts "racing" and would not kick down. It was like someone dropped a rocket engine in my car. It was very hard for me to get it to slow down muchless get it stopped. Anyone in the car feels the firm down shift when the car is slowing down and it does this twice before it comes to a stop. Recently though I have noticed that the idle is close to being back to normal yet when I attempt to "kick it down" the idle stays reved for a bit then drops down. We did notice that there is a hair line crack in the IAC on the underneath side directly in the center between the bolt holes and today I noticed that there is a crack on top of it also right at the right bolt if you are looking at it from the passenger side of the car. Any ideas on this mess will be greatly appreciated also.

God Bless You All!

P.S. We will be checking the sensor first thing tomorrow morning. I'm afraid to drive her for fear of messing up her engine or blowing her heads. I love my car and don't want to take any chances with her.
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post #9 of 14 (permalink) Old 06-22-2004, 09:30 PM
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You can get a new IAC from rockauto.com. For your year, they are selling for $56.79 at the time of this post. Check for vacuum leaks too. There are a lot of other things that could be causing high idle but I'd start there by replacing the part that is cracked.

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post #10 of 14 (permalink) Old 06-22-2004, 09:54 PM
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Thanks Al......I'll be doing the IAC this pay day. Hubby has checked for vac leaks, but hasn't found any. He did put some new clamps around a couple of hoses that looked as though they could be or might start leaking. I'm looking in my Haynes manual for a particular black hose that is small in diamater. It is located on the passenger side at the upper-back part of the engine compartment. It fits over a yellow colored tube and looks as though it leads over near the passenger door then inside the car to some point. I'm trying to track this hose down because it looks as though it is worn pretty badly in one spot. Trying to see where it goes and what it's for.

Thanks again for helping

God Bless!

P.S. I forgot to mention in my earlier post that my cars temp gauge had been staying around the M mark when it normally rides between bottom mark and the M. Sometimes it was getting up to the R and once it was up to the O. Hubby at that point took out the t-stat to see if that was the problem. Since then for the most part it rarely came off the bottom mark then it started riding up around the M again. It will drop back to it's normal riding position between the bottom mark and the M if I'm driving at slow speeds and not having to stop or sit. As I said before.......I'm very worried about driving my car like this for fear of damaging the engine or blowing the heads.
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post #11 of 14 (permalink) Old 06-23-2004, 10:51 AM
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UPDATE: Checked the sensor and it's toast. Around here it is a Ford only part and they want $81.31 for it and it has to be ordered and prepaid. Since the other parts were put on the temp gauge rides higher, now almost on the M instead of between bottom line and M. Hubby said it will do that since it's a 197 stat instead of the 192 that was taken out. I also noticed that there is now a faint bit of white exhaust now, but hubby said that it's just moisture even though it's hot down here in MS.

If anyone has any ideas where I might get that reservoir sensor for less than $82 please let me know. Right now I'm doing a internet search in hopes of finding a cheaper one.

God Bless!
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post #12 of 14 (permalink) Old 06-23-2004, 11:06 AM
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I'm sure Dan Newman would be cheaper than that.
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post #13 of 14 (permalink) Old 06-23-2004, 11:16 AM
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I just had my reserve tank off for doing the explorer swap. Mine had a float in it. There was alot of white/grey looking mud in the reserve tank, lower hose, etc. It was hard to see because it blended well with the color of the tank. This made a pretty good restriction and I am sure that enough of it would mess up the float. I would check for this build-up in the tank. You could also use something to manually move the float up and down to verify that it isn't working before buying parts. It might just be stuck.

something cheap to check first,

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post #14 of 14 (permalink) Old 06-23-2004, 01:24 PM
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the white smoke isn't a good sign on the 3.8. after warm up or driving if still doing the same thing then mostly be prepared to spend some bucks for the headgasket.

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