My '98 Plymouth Breeze makes this gurgling sound after I park the car and turn off the ignition. I opened up the hood one time recently when my car was making that gurgling sound and I discovered that the sound is coming from fluid that is flowing into the radiator's plastic tank. The fluid is fairly clear though, no signs of rust. This gurgling sound is quite noticeable. I can hear it in the car with the doors closed. I am not sure, but I don't think the sound lasts too long.
My car has nearly 90,000 miles on it and I am good about having maintenance done on it. This has been happening for the past few months. I just took a two hour drive in this car and it ran great, but it gurgled quite a bit at a rest stop and also, when I finally got home.
Is this sound a source for concern?
Yes. When I've heard gurgling noises like that, they've been because air is getting into the cooling system.... anything from a bad radiator cap (try that first, on the grounds that it's the easiest fix) to a cracked cylinder head.
That makes no sense at all...... when you turn the engine off and pressure in the system is above the limit that the caps specs are (normally 13-16psi) this noise will occur to relieve the pressure and overflow to the recovery tank.. A cracked cylinder head or blown head gasket would cause a overheating/loss of coolant condition before a gurgling noise. And wouldnt a bad cap cause loss of coolant before it would cause air to get into the system???
I've very seldom heard this from inside the car (though you're right, sometimes it is audible). When I've heard the gurgling when I wasn't actively listening for it, it's been from areas like inside the heater core.
There's enough excess capacity in the system that you can have some air in the system before you start overheating.
I've had "one-way" cooling system leaks twice; once from a head gasket and once from a cracked head. Pressure caused overflow into the overflow tank as expected, but when the engine cooled down and a vacuum formed in the cooling system, it pulled in air through the leak instead of from the overflow tank.
Yes but if you are getting pressure into the cooling system by means of the combustion system you will be raising the engine temp. I forget how many degrees the temp raises for each PSI.
Just curious but when you experienced those two problems didnt you notice the temperature gauge rising?
We're talking slow leaks here -- and as you pointed out, the radiator cap doesn't let the pressure actually rise. Besides which, I'm drawing a complete blank on how increasing the pressure in the coolant system could raise the temperature -- the thermostat and the engine fans aren't sensitive to the pressure. If it were a thermodynamically closed system then raising pressure would raise temperature (ideal gas law), but of course it isn't -- that's its whole point.
Not immediately. There was several weeks between the sound starting and my temp starting to climb.
Actually, it makes perfect sense. As long as the engine is running, coolant is flowing. When you shut the engine off, the heat soaked into the cylinder heads gets transferred to the (now stagnant) coolant in the heads and the local coolant temperature skyrockets. If the radiator cap isn't strong enough to maintain pressure, the coolant in the heads will boil and you get a gurgling noise and coolant puking into the recovery tank (or onto the ground in non-recovery systems). I've seen that on cars made from 1949 until the present, so its nothing new or unusual at all.