98 windstar over heating in the cold

replaced the thermostat last year. this winter, sometimes it is fine driving and does not over heat othertimes it overheats within 20 min. the heater blows cold before it overheats. is it still the thermostat or is it the water pump? please help

azchef

we live in ohio now not el centro ca. it is cold here...lol

1) Turn the engine off befor she burns up.
2) When the engine is cool, add 50/50 coolant/water mix until full @ cool line on your coolant reservior tank.
3) Start engine and turn Heat on max.
4) Do you feel heat @ normal operating Temp?

Yes - Watch heat & Temp guage & check coolant level tomorrow when cold.

No - Turn engine off

5) Need to do a coolant bleed procedure, because of air pockets in your coolant system.

A stuck thermostat could cause a over heated condition to loose coolant, or is coolant being lost, because of a leakey system?

Overheating can be cause by a sticking thermostat......HOWEVER.....when it comes with your heater going from HOT to cold (when in the hot position)....that sounds like AIR in the system.
You might have some air pockets still in the system that still need to be "burped" out, like has been mentioned.......
What I do......after working on the cooling system....that gets air into the system.....as a thermostat change will do......
I start the motor......let it idle......when the Temperature shoots UP.....I shut the motor OFF.....and let it cool.
Then I check the coolant level in BOTH the overflow bottle and in the radiator (you can tell by squeezing the upper radiator hose if there is a lot of air in the system that did not burp out through the overflow bottle.
Add coolant as needed.
Then restart the motor......monitor temperature......if the temperature shoots up......shut down......cool and recheck level.
It should only take 1 or at most 2 times to burp all the air out.

Please note.....it is NORMAL for the system to need to be burped of air after such a repair.
It is NOT normal for the condition to persist (as in to continue needing additional coolant).

Aside from that......if you have a constant coolant usage.....you have a problem.
Just a coolant can leak out of the system......air can leak in.
So....YES, it is possible to have air leak into the system.......and still have a full overflow bottle........and a low radiator level.

If the coolant level is OK.....no air in system......and the vehicle is overheating......heater cold......it 'could' be the water pump.
I think that the fins on the water pump are metal......so they should not be eaten away like the ones on (I think) the Contour were known to do.......
The water pump is driven by the same belt that the alternator and power steering are......so if it is the belt.....I would think that you would know it.

While it's possible that you have air in your system, the fact that you've operated the vehicle for a while since changing the thermostat without problems suggests that all the air has already been purged. Because you seeing problems only now that cold weather has hit implies that you have a problem with your coolant.

Make sure the coolant isn't freezing.

As Daniel mentioned, the coolant must be the right concentration of anitfreeze and distilled water. If it's off then the coolant will freeze, probably in the radiator and cause overheating of the engine.

You can purchase a device (~$3 at Autozone) to check your antifreeze condition. It also will indicate the freezing temperature of your coolant. If it's not @ 50/50, then add water or antifreeze to get it back to 50/50.

Are the rad fans coming on? Short of that I would suspect the thermostat. Always cheap to replace.

tomj76 has a reasonable cause of overheating in cold weather. In view of that fact that arctic weather has spread though cental US. your anti-freeze could be freezing in the radiator keeping hot coolant in the engine from circulating.

What a month with this van. We had a mechanic work on it and they replaced the timing chain gasket. That has seemed to fix the overheating problem. Now the van however is doing something it didn't do before it went in to the shop. Now, when it is driven the van will die when the RPM's get below the 1 mark. It only does this after the engine has had time to warm up. When stopping at a stop light or slowing down to make a turn the engine will just die. The mechanic says it is now the alternater that needs to be replaced. However, the vehichle starts immediately without the battery needing to be jump started. It kicks over strong. Even after sitting for a time without being driven it starts right up. I have been told it could be several different things...the mechanic messed up the timing, oxygen sensor, or vacuum leak...maybe they didn't connect a hose right or something to that effect. All I know is when it dies, I lose power steering and braking and this is of course a hazard while driving. In order to keep the van running it has to go into neutral while sitting or coming to a stop then put into drive to continue down the road. Any help here would be most appreciated. As I don't want to have to pay out more for something that isn't needed on this vehichle.

Thanks

Chefs wife:)

A common cause of the motor dying as you describe is the Idle Air Control (IAC) valve.
This is mounted on the throttle body.
It has a small motor that opens and closes a opening to let air into the motor.
This is how the computer controls the idle speed while your foot is not on the accellerator.
It keeps the motor from stalling or racing.

I would double check to see if the electrical connection to it has been plugged in.
The IAC is held in place by 2 small bolts, remove these bolts and spray some Seafoam "Deep Creep" or WD-40 up inside the IAC......while holding it so that the fluid will run out.
This will clean and lubricate the IAC....which often corrects that problem.

I am thinking that if they left something unplugged that would cause the problem.....it should cause the Check Engine Lighte (CEL) to come on, and you could get the code(s) read at your local AutoZone.....getting the actual code....and then troubleshoot from there.

A sticking IAC does not light the CEL, plus it is a common issue, which is why I mention it.
I have the IAC marked in yellow letters in this picture
http://rides.webshots.com/photo/2694966620011220610VszMOd

i checked the items that you suggested however, still looping on idle after it is warmed up. i have checked all connections and hoses. it is like it is not getting air or the timming is off. any other suggestions. by the way your pics of the engine were more help than you know....thanks

i have checkecd the IAC. I have also cleaned the IAC as instructed. I also checked the plug for the IAC with the key in the on position and the test light did not light up. does this mean that the IAC is bad or is there a fuze to change? lost.................

Idle Air control gets +12V through the red wire, MANY other things are on the same fuse.
The White with Light Blue stripe wire goes directly to pin 83 on the PCM.

The diagnostic charts for the idle issues have you eliminate any vaccum leaks,.....verify air filter is good......and is sealed, bad fuel, electrical connections.

If the vehicle did not do this before you went to the shop......I would have them check it over........if they think it is the alternator that is causing it....then it should NOT do this after the alternator is replaced.
A defective alternator 'could' cause all kinds of electrical issues......as could a battery.
They should be able to test the alternator for you for FREE at many auto part stores.
You might need to take it off of the vehicle.....although some places can test the battery and alternator on the vehicle.
I am trying to go with what your mechanic, who has actually looked over the vehicle, is telling you, but I don't want to see you replace the alternator if it is not causing the problem.
Some mechanics throw parts at a problem until it is fixed.........but most are good at their jobs, and dig in to find the root cause of the problem.

With the KEY ON, Engine not running, at the red wire on the IAC connector (unplugged from the IAC) you should have greater than 10.5V.
When the KEY is in the ON postion, you will have a lot of lights ON on your dashboard.
Lights, such as CEL, oil pressure, etc.
If not, you have not turned the key far enough.
If you do not have this voltage, then there is some open circuit condition in the wire harness......broken wire, disconnected wire.
If the fuse was blown.....the motor would not start.....as that fuse supplies so many items.

The IAC solenoid resistance should measure between 6 and 13 ohms.
Make SURE that the +lead of the meter is connected to the pin that the RED wire would go to and the -lead goes to the other pin.
Otherwise, you will get a lower (bad) reading due to a diode that is inside the unit.

With a meter, check the resistance between each pin of the IAC and the metal case of the IAC, resistance should be MORE THAN 10K ohms (10,000 ohms).

The next step, if you do not find a problem in the above steps, would be to verify the connection from the IAC to Pin 83 on the PCM.
As your mechanic is looking at a totally different possible cause (more likely than IAC if the above check out) I would advise looking into what they are before looking more at the IAC circuit.