So I recently purchased a close to stock FD and Ive been driving it with no problems. Ive already installed a Defi Water Temp gauge to monitor temps and have seen nothing above 95 degrees Celsius yet, it hasn't gotten warm here yet. Yesturday I was driving it fine with no problems and I got home and parked it and came out a couple of minutes later to hear a bubbling sound coming from it. I got in and turned the key to the on position, the fans turned on but the temp only read 80 degrees Celsius.

The only thing I can think of is that one of the radiator caps or AST cap are not holding the right pressure causing the water/coolant to boil at a lower temperature. The motor doesn't leak any coolant, and the motor has been recently rebuilt. I was wondering if there is something I am overlooking. I was planning on getting new radiator caps and making sure there are no air bubbles in the coolant. I do have the aluminum AST as well.

Any suggestions?

 

water boiling in the turbos would be my guess.

 

dont worry about it, its normal

 

Brodie- the sound is a little closer to the filler neck. It is a light sound though.

96fd3s- so does it always happen in your car? Do you just park and leave your car there to do its thing and cool down or do you wait for it to cool?

 

i havent heard it since i changed my coolant awhile back.
im not sure exactly what causes it buts its a commonly known occurance that is generally not considered a problem.

 

Anyone else know what causes it? So you just changed your coolant and nothing else? I might try that but I wont worry as much about it. Thanks.

 

I would recommend bleeding the air out of the cooling system, it can get trapped very easily and that could be what you are hearing.

 

Yeah I believe it’s caused by air in your system and as others have said it’s nothing to worry about. Mine did it (or does it) for years, then I went single and deleted the AST so I'm not sure if that eliminated it, but honestly I stopped listening for it years ago (that's why I'm not sure). Meh

P.S.- I find it refreshing that you are concerned about this. Given the plethora of issues that come up with these cars and the $$ involved in order to keep them on the road, most of us are jaded when it comes the weird little things. Kinda reminds me of me back in the day lol

 

I am no scientist but I have always associated it with being like a pot boiling on the stove. You have a heat source,(turbos). And there is air molacules trapped in the water that boil out. Once the heat source cools down (turbos) the boiling stops. This might be the reason for the AST, as there is no physical way of ever getting all of the air out of the system due to it being trapped in the coolant.

Mine also boils at cool-down, ^ this is always what I associated it with.

 

mine has done it for some time and the temps and stuff have been fine so i changed the caps. it was loud and the new caps made it happen less and not as loud but still does it i have some new parts coming in a few weeks. mostly cooling stuff so we will see if anything helps it out