94 escort temp gage goes to hot...

[raspy7]

the temp gage goes to hot and can overheat, but when i stop at a light or something the heater blows cold air. i had a new themostat put in but i still have the same problem. what else can it be?? please help me.

[mightymoose_22]

Your heater core is probably blocked. It is also possible that that valve that opens the heater is broken.

As far as the overheating... since the sensor is in the outlet hose from the heater core, perhaps the sensor has gone screwy if the flow is in fact restricted? Usually this results in an undercooling reading though.

Chances are, you have blockage in the heater core preventing you from getting warm air, and also blockage in the radiator causing the overheating. OR your water pump isn't working.

With the engine cool, start it up and feel the upper radiator hose... it should be squishy... as the engine warms up you should feel a pressure surge when the thermostat opens. No surge likely means the water pump is toast. If you do feel pressure, you need to find the blockage.

[tripletdaddy]

Does your heat guage fluctuate or just go to hot? If it goes up and down and you are getting some or no heat, you may have air trapped in the heater core. If you feel the two hoses to the heater core when the other hoses are warm, and they are not warm or not as hot as the rest, the core could be plugged. What does your temp guage do when you first start your car? If it immediately goes above normal, I'd think it's no good. I thought the valve for the heater core was no longer used and instead the coolant always went through the core, supposedly to avoid clogging, and the temperature of the air was varied by opening and closing doors in the ac heater unit that would blend hot and cold air to get the desired temperature.

One last thought. Does your radiator fan come on like it used to? I believe that turning on the defrost will force it on evenif the engine is hot, but it's a great way to see if the fan works. If it's not working, that could make things hot, but that wouldn't go along with no hot air from the inside heat. If you felt around under the dash where the blower fan, etc are, you should feel some warmth from the heater core if it is good.

[AzTumbleweed]

First thing to check is remove the radiator cap and make sure the radiator is full.

[raspy7]

the gauge fluctuates depending on if the car i moving or not, how fast i'm going, or if the heat or defost is on. when i start the car up it takes a while to get hot when i'm driving around. the car will cool off a little if i turn on the defrost.

[AzTumbleweed]

I think MightyMoose is on to something. Your symptoms would indicate a clogged radiator AND clogged heater core. When the engine gets good and hot then CAREFULLY feel the bottom portion of the radiator. If it is cold then the radiator is clogged. Whatever clogged the radiator might also have clogged the heater core.

[Selectron]

We can't really make a diagnosis from what you've told us so far, but if you could check a few things and get back to us then that would help a lot. I haven't worked on a faulty cooling system in years (touch wood) but I'd probably proceed in this order:


1. With engine COLD, check radiator coolant level (just because the level in the plastic expansion tank is good, that doesn't necessarily mean the level in the radiator is also good).

2. Check for heating of the upper radiator hose when thermostat opens (see post # 2 from mightymoose).

3. After thermostat opens and upper radiator hose heats up, the radiator should also heat up, so check for blocked radiator by carefully feeling lower portion of radiator (see post # 6 from AzTumbleweed).

4. Next I'd set the heater controls to provide heat, and check the heater hoses (from within the engine bay) at the point where they feed through the firewall - they should both be pretty hot, so a hot input hose with a cold output hose would indicate a blocked or airlocked heater core.


There are more checks to be made - the operation of the cooling fan(s) for example, but I think you'll find a problem with one or more of the items on the above list. Be careful when feeling the radiator temperature - keep your hands well clear of the fan blades, in case it switches on.

If you're not too familiar with cooling systems, there's an excellent guide on this page - you don't need to read all of it - just read this one brief section - How Does a Cooling System Work?:

http://www.familycar.com/Classroom/C...system%20work?

Then when you identify the problem area, you can read the relevant section in much greater detail. Let us know what you find, eh.

[Davescort97]

If you put the thermostat in backwards the temperature gauge will go to hot and it will block any heated coolant from going to the heater. The spring always goes towards the engine. Check it out. It's easy to do. If the top radiator hose doesn't get hot that's the problem.

[tripletdaddy]

That's different. I thought you made a mistake Dave, but after looking it up, I believe, just didn't expect it or thought they would want it that way. Would you know why? Plenty of other small engines are not that way. Having the thermostat backwards makes perfect sense for overheating and no heat. I wouldn't have thought of that being it since I didn't think the heater supply would be controlled by the tstat with the radiator upper hose. However, Raspy said the tstat was replaced to fix this problem but didn't in the first place. So, it sure'd be nice if all that needs to be done is the tstat, but am concerned it is not that easy.

[mightymoose_22]

I think that is partially correct... a backwards thermostat could casue blockage... but without looking at one I am not sure if it would even fit in there backwards.
The part I don't agree with is the lack of heat. The water pump feeds coolant through the heater core that completely bypasses the thermostat... the thermostat can't block flow to the heater. The only real possibilities for lack of heat are a blocked core or a lack of flow (busted pump).

[tripletdaddy]

I re-researched this business on the thermostat blocking or not the heater line. I'm with you MM22 on your assessment, as I also thought it was always one way. But what I found makes me say, it depends. Like I previously thought, it is less common for the tstat to control the heater hose supply, but it appears that it may on the 1.8L, but after a second look, the 1.9L is not blocked by the tstat even though it looks like it might. The 2.0L also is not blocked by the tstat. It appears the tstat can be reversed on all of the engines, but the 1.9L is less likely as it is an unique arrangment but still can be done wrong. If reversed on the 1.9L, it could cause some blockage. You'll see what I mean at the attached site. I used this webpage for reference:
http://www.autozone.com/servlet/UiBr...3d8013bd2c.jsp

Irregardless of the designed arrangement, it is worth a look at the tstat to be sure it is correctly installed and there are no other issues there, junk, whatever. Certainly all of the other possiblities, clogged core and or radiator, and worn pump blades are all worthy of investigating from easiest and cheapest to hardest and most expensive. Good luck.

[ebritt]

Most escort thermostats have the little wings on the tail end so you cant put them in backwards.

[denisond3]

The water temp gauge on my 92 Escort was reading too high, even though it would read a lot lower if I shut the engine down and immediately turned the igniton back on - but with the motor stopped. And the car wasnt using any coolant or otherwise seeming to be overheating. The situation was fixed when I put on a new ground cable from battery to the body, and re-grounded all of the wires that had formerly connected to the negative post on the battery.
Nothing else was affected - just the gauge read too high.

[Davescort97]

You're right. The stat couldn't go in backwards because there are tabs that line up with slots.

[raspy7]

i had my car checked out. they said it could be the waterpump but most likely it is the wires to the fan. the fan wasn't turning on. who ever had the car before me must have spliced the wires. i have to go back next week when the electrician is in.