coolant reservoir boiling
 

In need of help again! Here is what I have going on and what I have done so far. 2004 sebring 2.4 dohc. A week ago I was checking the oil and noticed the thermostat housing was cracked and leaking a small amount of coolant. I replaced the housing and thermostat then filled and bled the system. The next morning the reservoir boiled over and the temp gauge was reading just over 1/4. Took the car home and let it cool. I then let it run to observe the fans and see what was causing my problem. I noticed the fans never came on which caused the reservoir to boil over and the radiator hoses to collapse. Both fans run with a/c turned on and cool the vehicle if I turn it on just before the water starts boiling. replaced the coolant temp sensor and radiator cap for good measure and nothing changed. flushed coolant and confirmed no internal or external radiator clogs. I then checked the car for codes by cycling the key. None were listed. I removed each relay to check the fail safe modes and both run on high and low. Jumped the high relay and the high speeds work but nothing works when I jump the low speed relay. Supplied direct voltage to the fan assembly plug and high works but low does not. This seems strange to me because the fans ran on low speed in the fail safe mode. Going to buy alligator clips to be double sure the low speed does not work and make sure I am getting good contact in the plug. Before spending the $175 on the fans I'd like to make sure it is def the problem. Also, I bought the block tester kit and tested the car for hydrocarbons in the coolant. None are present. Any help??? I read dozens of similar posts but none resolve the issue. How do I bypass the pcm to ensure that isnt my problem with the low speed fan? the high speed fan comes on if I jump the coolant temp sensor wires and if I just unplug it. Guessing that's fail safe mode again tho.

56 views and not a single comment?!? C'mon now...somebody....ANYBODY!!! Need some help here please!! Don't make a grown man beg lol

do the fans work on there own or what? u tested stuff but never did say if they come on when the temp gets high.

The fans never come on unless the a/c is turned on. Once the system boils over no codes are set either. If I turn on the a/c just before the temp reaches halfway on the gauge the fans will run on high for a good while. The engine will cool then the fans cycle as they should.

the system will not coil water until its over 260 which is 3/4 or more not half
so what do u see or hear when u think its boiling

Most fans will not come on until 215 - 225

The water level in the reservoir starts to rise then I can see the water start smoking and seconds later it's boiling out the reservoir and steaming from the radiator cap then both hoses collapse. The temp gauge has never gone higher than about 3/8 on the dash but since this issue began I notice it regularly reads halfway and that's when it is boiling over. What I notice is that the vehicle realizes the extreme temp because if I turn on the a/c right as it boils over the fans stay on high speed for an extended amount of time.

did u bleed out all the air bubbles? also is the coolant circulating?

Might want to check for a crack in the reservoir. It's supposed to contain pressure but if it can't because of a crack, you will get boiling at lower temperatures. Maybe should pressure test the system.

Yes the coolant is circulating and yes I bled all the air out. The reservoir is NOT a pressurized container on this vehicle and I have pressurized the system and found no leaks or loss of pressure.

If it's boiling at a temperature that's too low, then it can only be the result of not enough pressure or improper coolant mix, or a leaking head gasket. You have ruled out the leaking head gasket. You have replaced the coolant. You have tested the system for pressure and found it good. Did you check the new pressure cap to verify that it was holding pressure?