Hey guys, I've been a long term member here and a lurker for a long time. I had other projects occupying my time so an FD was impractical (and still is... ) but I finally picked up my dream car two weeks ago, a '93 FD3S Touring!

Anyways, she runs great, but the only issue I have is this odd noise after I park her in my garage. It's a VERY audible "bubbling" noise coming from the engine bay, almost like a boiling noise. I don't think/hope it's not coolant boiling, but I think it's air bubbles being forced into the AST. I can also feel little pulses when I put my finger over the AST lid. I've heard this is an issue if air bubbles are present in the coolant system.

I was able to grab a short video of it on my Droid cell phone, sound is a little quiet in the video but in person it is pretty loud...sorry I moved it around a lot I was trying to find the exact source of the noise.

Car is stock except for a downpipe. Banzai Racing AST is on the way, too, along with some other reliability mods.



Thanks for the help!

 

Thats pretty normal.

After shutdown, the coolant starts to cool off and suck in coolant from the overflow tank. That is the sound you are hearing.

You've read the 3rd gen FAQ thread right? Especially the threads on the cooling system?
its the first thread stickied in this forum.

At some point, you should do a coolant system pressure test to verify that you don't have any leaks from old weak hose clamps and such.

 

OK, thanks.

Yes, I read the FAQ's, I just wanted to verify the sound. So it's nothing to really worry about?