I have a 2004 Sebring Sedan. 2.7 6V engine. I lately have been having problems with my coolant.

One day, I took him into the shop to get him checked because his check engine light was on and the mechanics found that my water pump and thermostat needed to be replaced (along with other things that doesn't have to do with the coolant system). So I let them proceed with the repairs and spent 3K on it. Got him back and he started back with bubbling like crazy. If I drove long enough, you could see steam coming from the side of the engine the reservoir is located. Took him back to the mechanic, they replaced the overflow cap since the seal was bad on the old one. Drove him again, he still bubbled, but didn't steam. Took him BACK to the mechanic, they drove him while pressure testing him and found nothing wrong. They did notice the check engine light was on that had a thermostat code. They didn't go in and check it though (which really pissed me off). So, for about 2 months, I just didn't drive him for very long. He only bubbles once he hits halfway on the thermostat on the dash. So my girlfriend, myself, and her family put him in their garage and spent 8 hours taking him apart to get to the thermostat. Took it out, tested it, worked fine. We bought a new one though just to be safe. Put everything back, test drove him till he got almost halfway up the thermostat gage to where I can hear him bubbling, turned him off and he was still bubbling. Is there any other causes to this? He has been pressure tested, pump was replaced, and nothing is leaking.

NOTE: I know it's summer and the weather is harsh on older cars, but I've had him for over a year now. He's only overheated once a year ago and the thermostat gage DID tell me he overheated. Filled him with coolant and haven't had to mess with it since.

 

Maybe the fans are not going on?

Maybe the temp sensor that tells the PCM to turn on the fans is bad?

Any codes/check engine light?

 

The fans turn on right as I turn on the car, but once I turn him off, they turn off.

Haven't checked that yet, it's under our list. Is that the temperature sensor?

Check engine light usually doesn't turn on for a few days after maintenance. It's currently off right now.

 

Somebody may have installed the thermostat backwards.

The fans are not supposed to be running all the time. They should not be coming on as soon as the engine starts. They should only come on when the coolant reaches a certain temperature. If they are coming on right away, there is something not right. The fans are controlled by the engine computer. If the computer senses something wrong (like lack of a good signal from the engine coolant temperature sensor) it will turn on the fans as a "fail-safe" mode.

 

We used the Haynes Repair manual and installed a new thermostat. The thermostat is in correctly, we checked. No leaks, no check engine light.

My fans turn on when I have my A/C running. Everything seems fine, but the bubbling. It seems to not hurt anything.

 

There are many possible causes for overheating. These would include a plugged radiator, both internal and external, improper antifreeze, improper mixture of antifreeze and water, collapsed radiator hose, failed thermostat, failed radiator cap, blown head gasket.
You'll need to rule out all possible causes one at a time until you narrow it down to the cause in your car. You seem to have addressed several of these already. Keep looking. Deal with the cheapest things first. The head gasket is the most expensive; leave that for last.

 

The thing is, he isn't overheating. He's just bubbling/gurgling.

 

Not overheating but boiling. Water boils at 212°F at sea level. Adding antifreeze will raise the boiling temperature significantly. Under pressure, the temperature of boiling raises even more.
The car's cooling system is designed to operate above 212° under normal conditions. The presence of a pressure cap and antifreeze are designed to prevent boiling under those conditions even though the temperature is above 212°.
So we are down to two possibilities: Improper antifreeze mixture and/or lack of pressure.
There are tests for both. Antifreeze can be tested for specific gravity (density) with a float tester. The system can be tested for its ability to hold pressure with the proper pressure testing equipment. Both the cap and the system should be tested.
If you spent $3000 for a water pump and thermostat replacement, the least they can do is find out why this "bubbling" is going on since then.

 

I have a 2003 Sebring, but mine is a 2.4, I had a bubbling problem a couple of years ago, and all I did to fix it was to replace coolant cap or radiator cap, which ever one you have. My car had a cap on the thermostat housing.

 

Any chance you have an air bubble in the system? Fill proceedure you must open the bleeder while filling the system to get as much air out as you can. trace ammounts will work their way out but a large amount of air may not.