Okay, here's the run-down. I have a 00 Concorde that's been overheating for the past 6 months & I cannot figure the cause. I have taken the car to 3 mechanics & even the Chrysler dealership & no one can pinpoint the problem. I have replaced the water pump, timing belt, radiator, v-belts, thermostat (x3), radiator hoses, radiator cap (x2), & bleeder valve. I have had 2 compression tests done & head gasket is fine. Car does not smoke & oil is okay. No visible leaks or coolant loss. Car has not lost any power & it runs normal. Had system flushed twice, & have bled the system too many times to count.
Car will run fine for 7 - 10 miles & start to overheat.
Could it be that heater hoses are bad? I haven't changed those & I thought that I heard fluid or something sloshing around in heater vents yesterday. Funny thing is that I drove the car at least 15 miles yesterday, & it didn't run hot until I pulled up in the driveway.
Can somebody help me out, please? It may be something simple that we've overlooked. I am so tired of dealing with this car!!!

Thanks

 

hmmm how about the cooling fans, are they coming on when it reaches normal operating temp, they could be bad or the temp sensor is bad.

 

no the sloshing is normal, mine done that for years...just hearing it circulate through the system upon start up.

 

what do you mean overheat?
my concorde engine seems hot when the needle is at normal operating temperature.

i dont know how the antifreeze runs around in the hoses.. but maybe the heater core is clogged and preventing some serious amount of coolant circulation.

i would ask if you have heat when you turn on the heater.. but its possible to have heat if the coolant heats up and touches the clog in the heater core, thus heating the core enough to have heat.
although, if this is true, the heater core should heat up slower than usual.

if you get in the car and drive it after the engine has sat long enough to completely cool down, you should notice an increase of heat from the heater vents after 5-7 minutes of driving.

you are right about the timing of the engine heating up.. because the heater core on my concorde is at about full operating tempurature within 1 or 2 miles of driving.
therefore, if you are having an issue at 7-10 miles.. that seems about right.

if i were you, i would first try to run the car without a thermostat at all.
that will, at the very least, allow you to drive the car further before it heats up.
because the thermostat is supposed to seperate the coolant in the radiator from the coolant in the engine.
the coolant in the engine is supposed to re-circulate over and over until the temperature is hot enough to open the thermostat and allow the hot coolant to mix with the coolant in the radiator.

i dont know what consequences this might have if the car's computer notices that the coolant isnt flowing as pre-programmed.
you might lose some horsepower as a punishment (safety precaution)
solid computer logic, such as that stated above, is always a frustrating battle when the change is not wanted.

anyways.. the second and only other thing that i would do is take the two hoses that go to the heater core and connect them with a piece of pipe to bypass the heater core.
that will have a significant change if the heater core is clogged and causing a problem with extra circulation.

make sure the radiator isnt blocked so that the coolant can be cooled by air as you drive.

my heater core isnt clogged at all, that i know of.
because after 7-10 miles, my heat is almost hot enough to make my skin itch.
my lebaron was worse.. lol
the heat was hot enough to make me think there might be a fire under the dashboard.

if neither of those two suggestions help.. maybe your coolant is inferior.

 

Thanks for the input.
I had temp sensor replaced the other day, and I was able to drive the car about 20 miles before it overheated. I then removed the high rad fan relay which allows the fans to run continuously while car is on. I drove the car for about an hour before it overheated. I'm starting to think that I may have a cracked or warped head??
Everything relating to cooling system has already been replaced.

 

its not the first time i have come across some metal that has changed its molecular structure.
i dont know if the heads or block would have to warp for the molecules to react differently to heat.
but its not impossible depending on the metal used to make the block and/or heads.

i can open my hood and it feels like 700 degrees F
but the needle says its a little bit lower than the middle.

maybe you have some metal made for nasa?
exotic..!

if antifreeze isnt boiling i wouldnt worry about it.
maybe the needle is wrong
maybe you are paranoid (because i think the heat from the engine at normal operating temperature is kinda high)

and if the engine is actually getting too hot.. maybe its for the best, because you dont know if its the heads or the block that is reacting to the heat abnormally.
therefore, it might be better to simply let the engine get hot.
if you are willing to buy new heads and put them on, you would might learn something.. but if its the block, you will have a pair of new heads to put in your closet.
maybe you could buy a remanufactured block without the heads and use those new heads.
but maybe the new block and/or heads need to be resurfaced before they can be matched for a solid fit.

again, if the antifreeze isnt boiling, i would just keep changing the oil and sensors that die and let time take its toll.
i havent heard or seen any of these engines with a need for a new headgasket.

i dont even know if my car needs a new headgasket.
but i am going to take the heads off and clean up the bottom of the head and the top of the piston (as well as the fuel injectors).
if i stop the oil leaks and gain 20-30hp it will be well worth it.
my car is running as slow as a slug.
i think i am just inches away from running like a lawnmower engine.

and anyways.. you said the engine performance is normal.
i dont know if the engine will run worse when the antifreeze is refusing to flow.. but it might be dream-y enough to help put your mind at ease.

 

Actually, the antifreeze is boiling & it will boil even if engine feels cool to the touch. Any ideas on this?
Thanks

 

are you a chemist holding a joke?

because i am well aware that molecules will move around more rapidly when they are hot.
and if you have a liquid medium that has a molecular structure that resembles boiling point, two things can happen.

1. the molecules can be denied rapid movement if there is an ensemble of molecules that create the liquid.
denying the movement by getting in the way should literally resist being heated up.

2. the other molecules in the liquid can be selected for their characteristics concerning heat.
if those molecules slow down when heated, they can be pushed along by the other 'boiling' molecules.
the constant movement would resist heat.

i suppose an ideal situation would be when the moveing molecules would stop moving when heated.. and the stationary molecules would begin to move when heated.
ensuring that each of the two flip from moving to non moving at about the same time.. it would result in a liquid that is hard pressed to begin rising in heat.. and then again hard pressed to get any hotter once the molecules have flipped their role.

a mosh pit at cool and high tempuratures should be enough to fan the problematic molecules that are accepting the heat.. either by forcing movement or denying movement.

anyways.. i only said all this because you asked for some ideas.

simply saying the antifreeze is boiling could be considered sarcasm if the person has a grasp of chemistry.
its physical boiling either way.. but one could say that one liquid is much hotter than the other liquid.
and depending on the amount of physical movement that those molecules provide, it could look like the antifreeze is extremely hot and boiling (minus some steam)
the importance is how hot the fluid is.. and how much is inside the cooling system to keep your engine protected.

i think the antifreeze that isnt specially designed to be extremely cooler than average antifreeze usually has a chance of letting off steam, which would put emphasis on the boiling movement.. as well as building up pressure inside the coolant system, which could blow a seal or gasket.

what you need to do is determine the amount of pressure taking place in various spots of the coolant system.
you dont want to blow a gasket on the thermostat or, even worse, the water pump.
these readings can be important information that will tell you if there is significant rise in pressure that could blow the water pump seal and force the antifreeze to mix with the oil.
so that means checking the pressure with the engine cool and again with the engine hot.

then you need to determine how hot the antifreeze is, because if its not extremely hot, you might be letting state-of-the-art coolant gush out of the coolant system when it should have been capped off to prevent any leakage.

what i have said about the molecules and racing coolant is a bit abnormal.. i know that already.
but i've already told you what can be said about the block and/or heads heating up abnormally quick.
you either need to decide if you want to keep them and get some of that state-of-the-art racing coolant.. or you need to try and determine what piece of the engine is heating up too fast.

i apologize, because an idea just dawned on me.
if you get one of those thermometers that allow you to point at something and get the heat reading, you could probably use that to point at the block and the heads to determine which one is heating up really fast.

if you start with a cold engine, you can watch the block get hot.. which will eventually make the heads get hot.
take a note for the block and the heads until the dashboard shows normal operating temp.
the block and the heads might be the same or a little bit different.
but once the engine starts to overheat, you should be able to clearly see which piece is overtaken by heat.

once you write down all the results.. there will be a vast amount of information to process.
either the block heats up the heads and the block continues to get hotter and hotter, which makes the heads get hotter and hotter.. or the heads will get hot before the block, and the heads will continue to get hotter and hotter.

last but not least,
the heads will get hot, then the block will get hot, then the heads will get hotter, then the block will get hotter, then the heads will get hotter, then the block will get hotter.

what would be best for you might be to watch the block and heads of a different car with the same size engine, and write down the results of an engine that isnt overheating.
that way you can compare your engine's heat up with a regular engine to see which piece of metal is growing hot too fast.

i just dont want you to take this advice and see that your heads are getting extra hot because the block is making the heads get extra hot.
you gotta take notes as the engine gets hotter.
i would do 30 or 60 second intervals so i can compare those intervals with an equal engine that isnt malfunctioning.

as you go down the line.. something will have higher numbers.
like for example.. if the block is overheating and the engine block is hotter than the heads, you know that the block is not cooling correctly.
and if the heads are hotter than the block, you need to know if the heads always follow suit with the block or if they have their own rising heat agenda.

i would think somebody must have checked the oil to make sure there was no antifreeze mixed in.
but you havent told us that grave bit of information.

if you disconnect a hose while the engine is cold and turn the engine on, the coolant should gush out, which tells you that the water pump is working.
it would be a real shame to have the water pump pulley spinning, but the actual impellar inside isnt spinning.

the options arent much here..
1. the metal soaks up heat at an abnormal rate
2. the coolant isnt cooling the engine (either because it isnt flowing or because the liquid is not capable of absorbing the heat)

have you ran anything besides coolant in the coolant system?
you might have glazed the metal with whatever 'else' you put in the system.
that could prevent the coolant from making contact with the metal to fully absorb the heat.

imagine this for an example..
if you have a metal plate that is on the stove and you turn the stove on very low, you can use your hand to absorb the heat from the metal plate for a short while.
but if you put something between the metal plate and your hand, that metal plate is going to get really hot before your hand feels the heat and begins to suck heat away from the metal plate.

a folded up towel will be slow enough to make the metal get hot before your hand feels it, but once your hand does feel the heat.. its gonna be hot and its gonna get hotter and hotter really really fast, until you remove your hand and say that you have been mildly burnt.
feeling some mild heat come from the towel doesnt count, because your hand isnt sucking up all of the heat from the metal.. no no no, your hand is trying to suck up the heat from the towel which is acting like insulation.

i think a towel is really too thick for a solid demonstration.
a new washcloth would be better.. or use one of those completely unabsorbant ones and fold it in half.
the key is using your hand to suck up the heat and prevent the metal plate from getting hot for as long as possible without burning your hand.

with the washcloth on top, the metal plate will already be hot before your hand feels it.
and once the heat starts to transfer to your hand.. there is going to be more heat and it will transfer in a furious rush, which is going to make you say ouch.
you dont need to know the exact tempurature of the metal plate.. all you need to know is how long the heat has been touching the plate and if your hand is helping the plate to stay cool.

the metal plate will probably be too hot to touch in only a few seconds.
but the success comes when you can use your hand to add two or three seconds to the time it takes for the metal to get hot.

glazing the coolant system because you used an additive can be catastrophic.
wind breakers are very thin.. but they can keep your body from lowering temperature in high winds, which is why they are made.

if you have indepth knowledge about computers.. you know that adding a cooling compound between the processor and the heatsink can really make a difference.
the cpu would probably overheat and break without the cooling compound.
and it also helps to note, each cooling compound is not the same.
some work better than others.


say you dont want to do any examples but want a better view as to what i am talking about.
picture a tub full of hot water.
if you sit down in it, your skin is going to say ouch the very instant you touch the water.
but if you are covered in grease, you will be able to dip into the water and not get burned.
baby oil might not be enough because it is a thin oil.
but cake batter or brownie batter is thick enough to get my point across to visualize it all in your head.

if you are a person that enjoys the discovery channel on television.. the 'mythbusters' did a scene about hot lead.
you can see that mini video here:
http://www.youtube.com/watch?v=UZio0f7fP04

see.. the coolant system chambers are supposed to be sensitive like a sunburn, if you touch the burn it hurts because the skin is raw.

maybe that is why you have changed things and havent seen an improvement.
it's certainly not far-fetched.

whats important to note, perhaps, is that a generic coolant flush might not remove the glaze.
and a flush that is too harsh might eat away a seal or gasket, or it might ruin the bearings on the water pump.

either one of these would probably dislodge any attempt to seal a leaking headgasket or hole in the radiator.

and if you do a radiator flush.. you might find holes that were previously sealed.

you should know that what i've said is true.
i was reading about antifreeze just last month.
the articles all said the same thing, the aluminum is very sensitive and requires a special formula of antifreeze to prevent corrosion.
because that corrosion will also act like a glaze and prevent the coolant from absorbing the heat.
i mean yea, the coolant will eventually get hot.. but that is when its already too late because the engine has already risen to a higher than normal temperature.

you might want to flush the coolant system because you dont know who did what before you owned the car.
but be aware.. you might see holes in the radiator or a leaking water pump gasket or a leaking headgasket as a result of the flush.

there are quite a few things that can be poured into the coolant system and cause a glaze.
radiator stop leak
headgasket stop leak
wrong type of antifreeze

if its possible.. check to know if the coolant system flush will remove those stop leak products AND corrosion.. or if only one or the other.

corrosion is typically rust and/or oxidation.
there are two ways to heal the problem.. one is to use an acid and eat away the glazed surface until new and cleaner metal is at the surface.

but the other method is much more involved, where the corrosion is actually melted back down into the metal.. kinda like hitting a nail with a hammer.

the more involved method is used usually only when an acid would remove vital molecules that are needed to keep the entire molecular assembly solid and strong and free from warping or twisting.

how important it is to do it right the first time might come at a cost that is unacceptable.
or maybe its simply too difficult to find anybody that knows metal with such great detail.

a simple radiator flush isnt all that much.
but needing a new radiator or a new water pump or new headgasket because you did a radiator flush.. well that is very annoying and if it happend without being prepared, you might have had a non-working car for quite some time until you could fix the new problems.


anyways.. i think i have given you just about everything there is concerning an overheating problem.

if your coolant system is glazed, racing coolant isnt going to help much because the heat will be absorbed from the glaze and not the metal of the block.
so if the block is 800 degrees.. the glaze might be only 500 or 600 degrees.
you would need some high quality coolant that is generally used to keep the temperature from rising at all (or maybe 400 degrees tops)

say, if your new coolant was designed to keep the engine at 400 degrees.. and the inside glaze is 500 degrees with the engine block at 800 degrees...
that means the racing coolant is only going to bring the temperature down 100 degrees which = 700 degrees on the block.

and a far-out problem that would put you over the top.. the new coolant reacts with the glaze and the coolant doesnt work like it should.
then you have wasted time and money on some better coolant, and as soon as you poured it in, it was like a drop of color dye being applied to a cup of clear water.


what some people fail to realize is that a glaze on the coolant system works both ways.
the coolant needs to touch the metal to absorb the heat.
then as the coolant cools down and becomes an ice cube for the block.. how can the engine benefit from the cool liquid if there is insulation between the metal and the cool liquid?

its like having a headache and/or fever and first place a dry washcloth on your head.. then place an ice cube on the washcloth.. you arent going to feel the ice cube at all until it melts and makes the washcloth wet.

that is why it doesnt matter if you disconnect the radiator and the heater core when you add a headgasket sealer into the coolant system IF the sealer is gonna leave behind a slime that glazes the coolant system.

once you re-connect the clean radiator and heater core, those two radiators will be able to cool down the coolant.. but once again, the engine block wont be able to feel the ice cube because its glazed.
its most important to have the inside of the coolant system totally clean.. inside the engine and inside the radiator and inside the heater core.

IF those head gasket sealers are going to leave a glaze behind, the clumped up seal needs to withstand a couple radiator flushes.
i would still be worried that the seal accumulates someplace and alters the throughput of the coolant passage.
(maybe for better.. maybe for worse)

changing a head gasket isnt all that hard.
the most important thing that comes to mind is the sealing surface.
again with the glaze.. you cant use any cleaner or degreaser that will leave a slime behind because the gasket wont be touching metal, it would be touching the slime.

i am waiting until next week to do my headgasket specifically because of the amount of water in the air.
the last week has had temps in the 40's
this week is going to have temps in the 50's and 60's .. but there is a chance of rain, which means there is lots of water in the air.
i dont need that water interfering with my seal.
you might not notice it until 1-2-3 years down the road.. but what causes a glaze on the sealing surface is harmful.. and having to replace the headgasket again is generally the consequence.

 

i want to apologize for the long post and take out a key point that needs to be made.
i feel it is kind to mention this key possibility as a side note, clear from all of the other paragraphs.

maybe you need to flush your coolant system.
the passages might have been lined with something if such an additive was poured into the coolant system.

if the coolant cannot make direct contact with the block, severe lack of cooling could result.

again, if you flush the coolant system with an acid.. you might spring a new leak in the radiator or headgasket or ruin your water pump gasket.. maybe even your thermostat gasket.

 

Thanks for your reply. I see that you know a lot about this! I guess I'll start by performing the tests that you mentioned since I do have a '03 300M that I can compare it to. Thanks again for all your help.