96 Plymouth Breeze gurgling sound

I have a 1996 Plymouth Breeze and its been a pretty trustworthy car for the last few years. Lately however I have noticed a gurgling sound coming from the coolant reservoir whenever it the thermostat gauge hits about 50%. It cools right back down to a little over 25% and the sound goes away. I don’t think its a leak in my head gasket as there is not any oil in my coolant or coolant in my oil, and its not over heating. Does anyone know what the cause of this sound is and should I be worried?

You’re definitely getting air in the coolant.
Mixing of oil and coolant being nonexistent does NOT mean you don’t have a headgasket leak. The headgasket has passages for both coolant and oil, and if the breech is such that does not include an oil passage you won’t get any mixing.

The most definitive way IMHO to find out of you have a headgasket leak is a leakdown test. It’s done with an inexpensive kit from the parts store. Each cylinder is rotated (you can do this by hand at the crank bolt) until both valves are closed and an air inlet with a gage and shutoff is inserted into the spark plug hole. Air pressure is pumped into the cylinder, the valve closed, and the amount of leakage monitored. Easy to follow instructions come with the kit.

Another way to test is with a lab strip. It’ll react to hydrocarbons in the coolant and change color. Again, you can buy these at any parts store and they come with instructions. A headgasket breech will allow combustion gasses to be blown through the breech into the water jacket, and this pumps more heat into the coolant than the cooling system is designed to dissipate, usually resulting in overheating, and also dilutes the oil, not good for the oil’s lubricating properties. It’ll trash the engine.

In your case I strongly recommend doing one of these tests. If you do have a blown headgasket, you need to find out ASAP. If not, then we can suggest other possible avenues of air entry into the cooling system. But a headgasket breech can be so destructive that I strongly suggest you check this first.

Post back. We do care.

+1 for @mountainbike.

I also agree with TSM. I believe that car came standard with the same 2.0L motor as the Neon. This motor is notorious for head gasket failures.

Another possibility is the coolant is boiling. This can happen – even when the dash temp gauge isn’t showing any unusual overheating – if the coolant pressure isn’t being held to as high of pressure as it is supposed to be. Unpressurized coolant boils at a lower temperature than pressurized coolant. In most cars the coolant would be boiling at normal operating temperature without it being pressurized. This coolant pressure control function on most cars is performed by the radiator cap. If that’s the case w/your car, replacing the radiator cap with a new one is probably the first step. It’s also possible the existing cap is ok, but gunk on one of the sealing surfaces is preventing a good seal.

@mountainbike I will be working on the brakes tomorrow and will get one of the test kits and report back the results. Thanks for the advice.

If the cooling system is full I wouldn’t suspect a damaged head gasket. Inspect the cooling system cap, it is located on the water outlet. If the the cap won’t hold pressure the coolant will boil a little before the radiator fan turns on. This is not unusual on the 2.0L engine.

I think the gurgling problem is most likely simply the radiator cap not holding pressure The rubber gasket cracks and fails in the cap . Replace the cap and see if it stops the gurgling. BTW I used to own a 95 Stratus and got 180K out of it before I traded it in. I did have to replace the radiator cap for the reason you mentioned.
The head gaskets failures on these engines were mostly external in that oil would leak out the side of the engine, and not an internal coolant leak in engine, that could be called a blown head gasket.

I pressure tested all of the cylinders and there were no problems. I replaced the radiator cap and just got back from a test drive through the mountains and not a sound. It appears that it was indeed a faulty radiator cap and the problem is solved. Thanks everyone for your help.

Thanks for closing the loop. Another factoid for the old memory bank!

Thanks for letting us know the outcome