cooling system problems - help

[CHOUKI240]

ok - heres whats up. i was driving it this morning for about 30 minutes... i pulled up into my garage and parked it. as i always do, i pull up the hood to let the cool air get in and cool it down better... then the coolant resivoir started to bubble and it fill up with nasty brown liquid. after a few minutes the radiator sucked it all back up and now theres no fluid in the resivoir. although yesterday i just changed the coolant. for about a month now, i have noticed that the green coolant has been getting browner everyday, but then today the day after i put new coolant in, all this brown stuff comes out. i'm thinking i need a new radiator, any suggestions/help?

[Pepperoni]

Id try to keep flushing it all out, adding water, keep flushing until it actually starts looking like water is coming out instead of brown liquid. Just sounds to me that it has a lot of crap (no pun intended) in there and needs to be cleaned out.

[CHOUKI240]

yeah...i'll be flushing the system out alot today. hopefully it will solve the problem, but i still can't get that it filled all the way up (almost to the point it was going to leak out)after i stopped the car...and then it went all the way back in. i'm thinking there might be some air pockets in either the radiator or the engine cooling system. but it doesn't overheat. trial and error time...

[BSeay]

that brown liquid isnt oil leaking in from your head gasket is it? you might have a fucked up head-gasket like my :sigh:

[misnomer]

As I recall, oil in coolant makes it look a bit milky. "Brown stuff" sounds more like rust and other crap dissolved in coolant. Remember: Oil and water don't mix.

Here is what it sounds like is happening:

1. Your coolant is boiling, thus the bubbling sound. Our engines operate above the boiling point of water. The cooling system relies on pressure to keep things from boiling. Lower pressure: lower boiling point.

2. Boiling coolant escapes as steam and sometimes may boil out of the reservoir. This lowers the amount of coolant in the system.

3. When you stop, the coolant boils for a bit, then stops as the engine cools. Steam still in the system changes back to water, and the water cools and takes less space, so it sucks your coolant back into the engine. You lost some when it was boiling, so all of the coolant gets sucked back in.


I'd place odds on it being your radiator cap-- assuming no leaks in the system, it is the cap which holds the pressure. You could pressure test the cap, but it's almost so cheap to replace that it isn't worth it. Flush your coolant well, refill it and bleed it. On DOHC motors, there is a bleed screw where the upper radiator hose goes into the engine. Remove that and fill until coolant comes out of the hole.

IMHO, it is a waste of effort to pop open the hood whenever you stop. The engine will cool just fine with the hood closed.