MY 2000 CHRYSLER 300M COOLANT IS BOILING OVER BUT CAR NOT OVERHEATING?

has the thermostat been checked?

the coolant seems to boil over when i park. far as i can tell it's when i drive for awhile or like more than 30 mins. i am soooooo glad that somebody replied, could i ask u a couple of questions? i purchased this car from an auction in febuary, in may i had car flushed cause it was boiling over brown greasy slug like stuff, i was told the gasket was fine but needed a flush cause it sat for awhile before i purchased it so i did. that helped for about a couple days then started up again, so took it to someone else and thats when i was told it needed a new radiator and holes so i replaced that.right before the fix i had to drive the car 30 miles to my machinic while it was overheating like every 10 minutes so ofcourse it took hours to get the car there, and i believe this blew the heater core cause it worked before the drive to machinic but now does not work only the AC works cause the machinic bypassed the heater core while fixing the radiator. now the car drives good, quiet, but sometime not everytime it will boil over. 1. can driving my car like this hurt it more, asking cause im a mobile phlebotomist and i drive my car every day for at least 5 hours a day for work, no car no job, so im very worried? 2. the car had 112,000 miles on when i boughth it, now it has 118,000 all the problems that i have had already in the last 4 month, do you think i should get rid of the car, i have heard bad things about chrysler's and i can afford to have a car that will always has so type of problem cause i rely heavily on my car for work, so wondering if the fix is minor or major to help deside weather to keep it. 3. there is a holes that leads to the coolant container, someone took off the clam that connect it to the coolant container, the hole is on it but just not securly connect, does this bare any weight as far as the problems im having? 4. if there is a way i can check the thermastat by my self can you please tell me, an a affort to safe a buck? 5. if there is anything else that i could check my self, please let me no, and any thing i need a machanic to check out please tell me, thanks sooo much for your reply, hope to here from you soon

what colour is the coolant now? green or orange? and is it becoming oily and strange in colour still? this would indicate a contaminant / leak in the system. bypassing the heater core will no longer provide heat to the interior of your vehicle, so it you live in a cold climate... the thermostat is usually the cheapest and first thing to check. one can usually check the condition of the thermostat by squeezing the upper radiator hose when the motor is cold and feeling for pressure. no pressure in the hose indicates the thermostat is open. pressure in the hose is causes by a system full of coolant and a thermostat which is in closed position. clamps on all hoses should be used. heat and pressure will build up and a missing clamp will push the hose off resulting in a leak, or worse overheating, overheating will result in mechanical failure. also check the waterpump.

the coolant is light green now with a slight kinda tan color, if it gets to point where it overheats and boils over yes it is kinda greasy, but only when over heating or if i drive long and it doesnt over heat it will just boil over and is tan in color with slight green. when cool its green, sometimes i check it before i drive and stick something to look at color. how do you check the water pump or is that something a machanic has to do?

Mechanic is best to check the water pump. And while at the mechanic, they can replace the thermostat and clamp all the hoses. If the problem still continues after this repair, the mechanic should pressure test the system. Worst fear is a cracked block or manifold.

thank you, was alot going on so didnt get online but do you no that the coolant boiling over problem has totally stopped, the car hasnt overheated at all, has been running prefectly fine. this is soooo weird. the same day i started emailing you it was boiling over , i opened it and let some just flow out for about 3 seconds, then closed it and sence then no problems at all, do you think maybe there was too much coolant in the car or should i still have water pump looked at and thermostat replaced? i sure i need a clamp but was just wondering what you thought about the other stuff sence i havent had a problem in about 5 days, what do you think? thanks

Has the weather been cooler since the last time? Or have the trips been shorter (less time to build up heat in the fluid)? Overfilling might be the cause... is the overflow reservoir at the "full when hot" mark?

WELL THE WEATHER HAS BEEN IN THE 90'S, AND THE LAST 3 DAYS OVER 100,THE TRIP HAVE PROABLY BEEN LONGER, WENT TO THE BEACH LIKE AN HOUR AWAY YESTERDAY AND I DRIVE ABOUT 30 MINS TO AN HOUR AWAY EVERYDAY. I CANT REALLY TELL IF THE RESERVOIR IS FULL, THE CONTAINER IS STAINED KINDA, PROABLY FROM WHEN IT WAS OVERHEATING AND LEAKING, IM GOING TO CLEAN IT TOMORROW AND CHECK AGAIN THO

Sounds fine now that the temperature has been warmer and no sign of overheating. All the best then. =)

I have a Chrysler 300 M

my 2000 300 m is doing the same thing. I'm going to buy a new radiator cap. sense there's no real radiator cap on the radiator this one is located on the resovior that boils over. The pressure seems to only build up when I stop the car.when I relieve the cap a little bit the pressure is released and it quits boiling over.

it sounds like you had some air in the hoses mine did the same thing i jusy yook that cap off and let it run out for a couple seconds til it pushed the air pocked out the it started going back down and i hurried up and poured more in so it didnt suck more air til it was full and it fixed it never happened again theres also a little bolt on some cars on the line u unscrew til antifreeze starts to run out then screw it back tight and that gets all the air out of your lines

If your coolant is getting greasy and brown, chances are you have a blown head gasket or cracked block. That greasy brown sludge is the result of oil mixing with the coolant.

I'm having the same problems...is this something with this brand of car? We replace dthe radiator and before that the fans because one broke...you let it idle and it bubble , bubble , toils and trouble!

I have 2004 300m that was boiling over it sat for awhile as well. A simple flush just wasn't enough I had to spraywater directly in the radiator cause it wouldn't drain. there was a lot of gunk. So the I had to remove the cooling fans to get to it ( got the instructions from the internet ). Anyway the 300M manufacture calls for the red anti freeze. I doen't no why, but my car temp. runs below the half mark now....just saying

~~laughing~~..The car is toast now....We put a new radiator on it, thermostat and a few other things and it still kept overheating , now sounds like it's blown up. We don't drive it anymore and it's probably going to be sold for parts...Thanks for answering!

I'm beginning to think the clamps were not put on properly. I just had radiator replaced in winter and now its summer. Just makes since to me

as a bone. next check the thermostat? the thermostat should stay closed until the engines coolant reaches a certain predetermined temperature. if you start the engine when cold with the thermostat off. the coolant inside the radiator as you look in it, should not be circulating, because when a car is cols the thermostat should be closed. you can use a temperature gauge in the radiator to tell when it opens. when that water starts to circulate, the thermostat is open., if the thermostat is also fine that narrows it down to water pump or head gasket problem and possibly a problem with the block itself. at which point you should be praying for a bad water pump. If it is not the water pump it is the head gasket or the block itself has a crack in it. it has to be one of those components because you systematically eliminated the other components from causing the problem. s sio by a relatively easy and quick process of elimination you have discovered that you have water in your oil and low compression on cylinder number three, which means poor devil you have a blown head gasket. this is not saying that this is your problem, but it is how anyone can go about trouble shooting an over heating car. most important stop driving the damn car as soon as you know it has a problem. DO NOT EVER PUT WATER IN A HOT ENGINE UNLESS IT IS RUNNING! even then be careful. good luck. that will be sixteeeen thouuuuuuuusand dollars consolation fee if you please. Perfection detail Master Detailer, out

I recently had the same problem with my 300 to save everyone a headache it's the water pump.after having my radiator, thermostat,and sensor replaced the car was still running hot and only boiling over when I stopped after driving ,come to find out it was the water pump in which is control by the timing belt,both have to be replaced at the same time and your problem is solved

For all those coolant has that greenish brown color or if you notice black particle in your coolant...1u nd a head gasket change if the color is greenish brown...if you see black particles in your coollant, then you most definitely need an engine flush, if it reappears again, you'll need a new heater core.

Change your Antifreeze Fluid reservoir CAP? they get old, and don't keep the pressure in.

I have a 2008 Chrysler 300 and I was just sitting in the car with it running at an outside temp of maybe 95 and I was parked for maybe 45 minutes and all the sudden u just start hearing plastic breaking and the car starts sputtering and I turned the car off to find all my radiator fluid was pouring out the bottom of radiator but the car has never over heated! Seems like pieces of the fan have also broken off! Can anyone tell me what could of caused this