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Discussion Starter #1
After searching these forums, I found an almost the same situation that I have with my Aries K 1989 sedan. The car when first started in the morning, and driving down the road about 10 to 15 minutes, the heat guage goes almost up into the hot zone. It's stops just below that, and then the gauge drops to cool and for the rest of the driving time, never moves off cool zone. The other thread says this is a thermostat problem, and I should replace it. Which one should I get? My local Autozone shows only three brands, Duralast, Failsafe, and valucraft; no mopar. I know I also need the gasket. I was wondering which one to get because each shows a different temperature, 190, 192. 160 and 180. Would appreciate any answer I am given. Thanks in advance.
 

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For best results, I always use the factory recommended range, that would be in the 190-195º range for a stock engine.

However, it may not be the thermostat that is faulty. It is quite possible the cooling system is sucking air in somewhere when it cools. That air forms a pocket against the thermostat and won't open the thermostat like water would. This is why many will recommend drilling a small hole in the thermostat so the air bleeds through. But my experience has been once you're getting air in the system, it's a good idea to find out why. it could be as serious as a head gasket or as simple as a as radiator cap or leak hole or weak hose clamp. So I'd recommend a two step approach - put a new thermostat with a bleed hole in and then pressure test the cooling system for leaks.
 

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Thanks. I don't have a lot of money to pay someone to do what needs done. One of my brother's owned this car before I got it and he said he put a new thermostat in there last year or year before, he can't remember. I also read that air could cause this problem too. How would I do a pressure test? Also, if it's the head gasket, wouldn't I see a leak?
I'll have to ask him if he changed radiator caps or not. I am sure he didn't know about the air or that he put a bleed hole in the thermostat either.

If I put in a new thermostat, where do I put the hole? I have dremel tool that should work for doing that.
 

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You can likely rent a coolant system pressure tester at an auto parts store, sometimes it's free though you have to leave a deposit. You'd want to pressurize the system with the car off and see if it holds pressure (I'll bet it won't). You can also test the radiator cap. And you can run the car with the pressure tester attached and if the head gasket is an issue you'd see that by the high pressures.
The head gasket failure will usually put some oil in the coolant and some coolant in the oil. All that's necessary is a small hole, 1/16" or so drilled in the flat part of the thermostat, obviously in far enough it's not covered by the gasket.
 

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Discussion Starter #5
Thanks Mark. I don't think it is the head gasket though, I've seen nothing other than oil on the stick nor have I seen any oil in the coolant. I know what to look for there, my late husband was a certified Ford mechanic for 30 years but I forgot most of what he tried to teach me, except for some things, i.e. I could not rebuild a motor and/or set timing; however,. I can still change my own oil, and spark plugs. I will check with the local parts houses to see how much it would cost to get a pressure tester. Thank you so much for your very explicit answers. I'll keep you posted how it goes after I get the test done, or maybe before. ;)

One thing I forgot to mention. Every day I check the water in the radiator, it usually is lower than the neck, sometimes it's below the neck and not covering the radiator fins, there is water in the reservoir though. I remember my husband putting water only in the reservoir, should I still do that or should I fill the radiator itself?
 

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If the system is in good condition, you should only need to add water to the reservoir. As the engine cools, there would be a vacuum that draws the overflow reservoir coolant back into the radiator. Since it appears it may not be drawing back in from the reservoir, that's even more of an indication there's a leak somewhere, like mentioned as simple as a hose/clamp or the radiator clamp. Keeping on top of the coolant level like you are will greatly reduce the chances of overheating damaging the head gasket.

If you can't borrow or rent a pressure tester inexpensively, you might want to visually look at the radiator cap. If it looks bad, especially the seal, you might want to replace it when you do the thermostat. It could easily be bad and why the coolant does not seem to come back from the reservoir.
 

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Discussion Starter #7
I'm going to try a cap first because looking at new ones, the rubber on mine is flat against the cap inside. And I don't think it has been changed in a long while. Just thinking and looking at Autozone, the caps they show as in stock, one is a pressure release type, would that be good to get? Or should I just buy the regular style?
 

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Either type would work, but my experience has been the pressure relief type just don't seem to keep a good seal near as long as a standard cap.
 

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Discussion Starter #9
Thanks Mark. I will go standard cap then. It's also less money for the standard. And I never knew that about the pressure relief type. And more knowledge for me. :)
 

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Not to deter you from what else is going on, but I had this happen with my Barracuda after I overheated her a very long time ago.
There is a condition called carbon tracking of the head gasket. At some point the engine may have overheated and in the process, smashes the head gasket a little bit more than normal, so when she cools, engine compression pushes gasses through the head gasket ring to the water jacket, and when she warms up she is fine. The temp rising and then dropping is the thermostat opening, if compression is pushing the gasses into the water jacket around the head, it displaces the fluids, the temp goes up, the thermostat opens and fluids rush in and the temp stabilizes.

We have had a couple radiator fixes, purges and such in the past couple weeks, so again, have the front of the car higher than the rear, so air naturally goes towards the radiator. Turn on the heater full hot so it is flowing, remove the radiator cap, fill. Start the car, rev her a few times and let her get warm, the fluid will start to overflow and should run into the overflow tank. Fill the overflow tank between the hot and cold marks, cap the radiator and then watch the overflow just a bit. You should be able to squeeze the upper radiator hose and have fluid go back and forth and see the level change in the overflow tank.

If you put another thermostat in her, do drill a 1/8th inch hole, in the flat part, or at a minimum, depending on your tool selection, poke two nail holes in it. Use the 192 degree stat, which is factory temp needed for the computer systems to function.

Also, if after the above is done to get the engine full of fluids, if you see steady bubbles coming into the overflow container, smell it. It will smell like antifreeze, sure, but if it smells like gas or exhaust, the bad news I started with is happening. Sometimes they will last a week, sometime a month, and retorquing the head will not fix the problem because the seals around the cylinders has been permanently compromised.
 

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Discussion Starter #11
This problem I'm having has been doing this for two years. That's another reason I don't believe it is the head gasket or head. And this car doesn't have a heater, well, the components are there, it just doesn't work.
I bought the cap today, and will test tomorrow whether that was the problem or not.
 

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lets
 

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also if you have garggling in the rad or coolent system, that also means a bad headgasket
The gurgling only means there's air in the system, it doesn't necessarily mean the air is there from a blown head gasket.
 

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Discussion Starter #14
I've never heard gurgling in any situation here. The first time this happened to me while driving, I pulled off the road and left it running while I filled the radiator, there was no gurgling sound. And my heater/air conditioner switches are sliders, no red zone indicator.

Let me say this first. I appreciate you all jumping in to help, but I need to proceed as I'm doing first then if that doesn't work, (new cap), then I'll try the thermostat idea. If that doesn't fix it then we can proceed to other ideas. I still don't believe it's the head gasket, since it's been doing the same thing for two years, wouldn't it be obvious now that the head gasket is blown? Like it would overheat to cause more damage. The car doesn't overheat. Yesterday I went to the store, on the way home (less than a mile) the gauge moved up as it has been doing, then it went down again. Once home, I popped the hood and went inside for about 15 minutes, went out to check if the cap on there was cool enough for me to remove and place the new cap on. I touched the cap, and it was cool to the touch. If this was actually overheating, I could not have touched that cap at all. Now I will say it one more time so you extra helpers understand.....the car is not overheating.
 

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While you are working on it, I have a question about the heater. Does it blow air out? And if so, is it just not getting warm? These heaters are notorious for plugging up and not generating heat. A cheap fix is to pull the heater hose and force water through the heater from a garden hose in the opposite direction of the normal flow. If all kinds of gunk come out, you may find the heater would work. The only reason I mention this is since you've already planned to open the cooling system for the thermostat, doing this will cost little extra (maybe some heater hose and a little more antifreeze). Just be careful of not breaking or otherwise damaging the ends of the heater core where it comes through the firewall. Of course, it could be a problem in the temperature controls and not the plugged heater core. I can't remember how your car controls the heat, many had a cable that was subject to breaking or kinking meaning the temp selector doesn't more anything.

I'm with you, I don't believe it's the head gasket - though if you weren't as careful as you are topping it off it could easily really overheat and blow the gasket.
 

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Discussion Starter #16
Mark, I really don't know about the heater except my brother said it didn't work. I've never turned it on to find out. I could try your suggestion to see if it would blow heat of any kind. Right now I'm in the middle of reinstalling an OS on a computer so I can't stop and go out there to check. I have not driven the car yet today, so I still don't know about the new cap affect either.
 

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OK, not head gasket is the consensus, but air in the system definitely. Agree with ensuring the air is not stuck in the heater core, if it is plugged or not flowing well, air could be in there and be just kind of a bladder for expansion. Historically these engines have been difficult to burp, and it only takes about a cup of air volumentrically to do this type of problem (borderline overheating then settling down), little pockest are in the head casting and it takes some work to get it to get forced out. Explain the heater core situation a ltitle better as far as function goes. I don't think we are really arguing the situation, it's just another case of finding more information as we discuss your situation that changes things to check, verify and get the end results that are positive.
 

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Discussion Starter #18
I will not know anything to tell you all until tomorrow. I am still working on this blasted computer, running tests now since it refused to let me update XP. :(
 

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Well, the cap didn't fix it, but the needle didn't rise as high before quickly returning to the cool end. Thermostat next or compression test first? As for the heater explanation, I don't really now. I didn't turn it one while the engine was running but without the engine running the only air felt is where the defrost would be. Tomorrow, if I remember, I'll try it with the engine running.

I have another problem with this car also and from what I've been told it has been going on since my oldest brother bought the car, more than two years ago. I don't know if it has anything to do with this problem, so I'll hold off on telling you about that until we get this other worked out.
 

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You have to have the heater on full blast hot, without the fan to begin with, because there is a valve that shuts the water off to prevent heat from flowing all the time. If fluid is lost, this area can become an air pocket, thus, no matter how many times you bleed it, you are always going to have an air pocket in there, thus she will always overheat/heat weird. Before the thermostat change, turn the heater on to the hottest setting and do the bleeding test again, front end lifted up, or parked on a steep incline, front of the car on top to help purge as much as possible.
 
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