BoostedD15B7

When i got home from cruising i shut off my car and i heard a bubbling sound. I though right away that it was the radiator boiling. So i turned the key on and the temp was fine and the fan didnt kick on. Got out and poped my hood and my over flow was full and air was coming through the hose creating bubbles in the over flow tank. what would cause this? Thermostat?

JDMvtecDRAGSTA

thermostat.
its not opening up.

BoostedD15B7

anyone else say thermostat too?

Thudpucker

It's normal for Fluid to go into the Catch Tank after you shut the engine off. What's not normal is the "Bubbeling" The 'Cooking' causes the fluid to expand and the Radiator cap is supposed to let the expanding fluid by, into the Catch tank.
"Bubbeling" means Boiling...Too Hot! Air Bubbles mean the water is being turned into a Gas!

The following is my way of troubleshooting the "overheating"~~~

If it's expanding out of the Radiator, past the Radiator Cap, it would mean the normal 'cooking' after a use.
That fluid from the Radiator, should go back into the Radiator when the system cool's. "Bubbeling" might mean, and this is an easy one, you might just be low on coolant?

Does the Coolant go back up out of the Overflow tank, and into the Radiator?
If not, your tube between the Radiator and the bottom of the Catch Tank may have an air leak in it somewhere?
Or the Radiator Cap has a leak, or you may have a leak somewhere else in the system.

If it's not actually overheated, but still going past the Radiator Cap, it may mean the Cap is not holding the 14Lbs of pressure it's supposed to?

If the engine is actually hot enough to boil the 50/50 Anti-freez mix, and still the Fan does not turn on, it may be the Thermosensor, Fan or wiring connections?
There's two Thermo Sensors in the 3rd Gen engines. One you can see easy, at the Bottom of the Radiator, and the impossible one to see, under the intake Manifold in the back of the Block, just over the Oil Filter.

And finally, if it's actually over heating, which doesn't seem likely, because the engine runs fine and the fan must be working, then my first thing to change would be the Thermostat!

But there's other things as well. Like the Condition of your Radiator, the age of your coolant mix, the whole system might need a flush....
There's a bleed screw to let the system fill up. Dont forget to check that.
All this and I dont even know what kind of engine we are talking about!
Good Luck....Be diligent.....Dont cook a good engine by guessing!

hondafrk

Im having the exact same problem with my 92 dx right now. The coolant goes into the overflow but wont go back into the radiator when it cools. I have to wait until the motor cools down and I have to add the coolant from the overflow back into the radiator. I changed my radiator cap and It still does it but not as bad. Before I had to empty the overflow every day or so, now it is only like once a week or so. I also have changed my t-stat a year ago and I dont think that it is causing it. Some people have told me that my water pump could be going bad or maybe even my headgasket may be leaking but I dont seem to be losing any coolant. My engine is just displacing it into the overflow and after I add the coolant back to the radiator it is still between the min and max lines on the overflow bottle. let me know what you find.

cooling system problems

BoostedD15B7

I replaced my thermostat yesterday and drove to my girl's house, then home later on and i heard nothing. Im going to drive around alot today and check it so i no for sure its fixed. But just so you know.......My thermostat was replaced like 8 months ago, but i think thats what it was. Maybe it was just one of those shitty auto zone ones crapping out. Im going to order a Jackson Racing 160 degree.

hondafrk

IM me to let me know what you find
thanks

BoostedD15B7

****.......I replaced the thermostat like 2 or 3 weeks ago and it has been running fine. Now tonight i hear the same bubbling. Cooling fan kicks on, but temp looks fine on the gauge. I think the gauge is working right because it moves up slowly when warming up.. THink i may just need a bigger radiator????????????????????/