Chrysler Repair: follow up for chrysler concorde 2000 3.2, chrysler concorde lxi, 2000 chrysler concorde lxi

Question
i asked my problem to another tech guy and he send me some info, and i need more but he is not avaiable. so i would like to ask it to you. my car is 2000 chrysler concorde lxi 3.2 at 160k miles

Subject   2000 chrysler overheating irratically


Question   my car overheats unexpectedly. for aexample i drove for 3 hours in traffic jams mostly during noon and nothing happened. but when i tried to go dinner, it overheated just in couple of minutes. i already changed timing belt, water pump, radiator cap,coolant but nothing changed. when itt over heats coolant boils in the overflow bottle and steam comes out. there is nothing wrong about the exhoust (i mean no water in it)and radiotor fan works in both high and low levels. sometimes it over heats even driving at 70 miles.and one more thing: when the heat level passes the middle of the thermometer gauge, it makes jumpes like 1/8 of the gauge. also when the tempature drops (sometimes it drops just while working)it drops suddenly rather than graduaaal. i really need help about it cause my mechqnic has nno idea about it.


Answer   Hi Alper,
You didn't say which engine you have so let me know that if you do a follow-up question. Here are some observations and suggestions:
While it is good there is no water in the exhaust, you might want to see if you have a cloudiness in the oil which can also be contaminated by water, in the case of a head gasket leak.
You may have a problem with air trapped in the thermostat housing or other area of the system. That air can cause the thermostat to fail to open promptly if it is in the thermostat housing and conversely to open promptly when the air is cleared. That would be a cause of rapid rise and rapid fall of the gauge. There is a special procedure you need to follow to refill the system to avoid that, so if your recently drained and refilled the system that may be the cause. I can xerox and postal mail the procedure for that if you have the 3.5L engine.
Do the fans come on when the gauge reads hot? I would stop at the time when the gauge is moving up quickly to check that. If not, that fan control circuit is the problem.
On the waterpump: the 3.5L pump is driven by the timing belt so if you don't need a timing belt change out it would be wise to only get into that issue when you have tried the other approaches first. It is a fairly big/expensive job to change the pump, so that is why most people recommend doing that only when the timing belt is showing sign of wear out and then you change the pump regardless of its condition.
I won't be available for 5 days after today, so see what you can conclude about some of these ideas.
Roland

FOLLOW UP
There is no cloudyness in oil. and when my car is hot the radiator fan works without a problem, it never stops until car cools down. i already changed my timing belt and water pump when i first bought the car also 2 months ago my fan burned so i changed it too. maybe when my fan burned, my car lost too much water and we added same kind coolant. also i had my heat problem regardless of all the other timing belt or fan problems.
if air trapped in thermostat, i would like to learn proper way to drain and refill the coolant. in addition i can change thermostat if necessarry.
i'm stuck now, so i really need your help.

Answer
It sounds like you've done alot to this car that could either help or create your problem.  If you've got the 3.2 or 3.5L engine then you also have a bleeder screw that will help purge out the air as you fill it up.  The coolant resevior sits pretty high on this car so getting all the air out is difficult.

The bleeder screw is located between the intake runners either one or two runners towards the rear or directly at the front where the upper radiator hose meets the intake manifold.  It is hex shaped and has a little nipple on the end.  With the engine cold, remove the radiator cap.  Once removed, open up this bleeder screw.  It's normally a 10mm head fitting.  Keep this open whild adding coolant to the resevior.  You can keep a check on the level by squeezing the upper radiator hose.  When you squeeze it and coolant squirts out then you are getting close to full.  Continue to fill until coolant comes out by itself.  

Close the bleeder, make sure the resevior is filled to spec and put the cap back on.  Do all of this with the engine cold to prevent from burning yourself.

Once everything is sealed back up, crank up the car and let it run for a while.  Keep an eye on your temperature guage, make sure both cooling fans come on should the temp get pretty high.  Expect one fan to come on when the gauge gets over half-way.  One or both fans will come on when you turn on the a/c.  Verify that at least one comes on with the a/c.

Let me or Roland know what you find.
Doug