Originally Posted by 02_camaroz28

Make sure your coolant in your overflow is full because if not it will not turn on your fans.

Originally Posted by wssix99

I think there are two possibilities at this point that folks here are pointing you to: (It sounds like folks are feeling like #1 is it.)

1) NOT boiling http://en.wikipedia.org/wiki/Boiling
Boiling is water turning to a gas and escaping from the system. IF your coolant is the right mix and IF your temperature gauge is not lying to you, then you just have fresh air getting in to the system. The coolant system on these cars is a sealed system and the overflow tank maintains a siphon with the system and transfers coolant back and forth to regulate pressure in the radiator as coolant expands/contracts. If you have a leaking gasket or a bad radiator cap that doesn't seal, then you can get air in to the system. (Especially when you turn the engine off, which turns the water pump/pressure off, and the coolant starts to contract in the radiator.)

2) IS boiling
IF your system is sealed properly and IF your temperature gauge is not lying to you, then your coolant to water ratio is off. You should be able to purchase a special hydrometer http://en.wikipedia.org/wiki/Hydrometer from your local auto parts store to test this.

So... there are a number of causes that could lead to the two instances above. I'd suggest going in this order due to probability of cause and the cost involved:

- Buy a new radiator cap (Be sure to get a GM/AC Delco cap and not an aftermarket cap from your local auto parts store. The GM cap has a special pressure relief that will prevent the plastic parts of your radiator from imploding in the event your overflow siphon gets stopped up. The aftermarket caps do not have this feature.)
- Steal your Mom's meat thermometer and test the temperature of your coolant to see if your temp sensor is bad. (Keep in mind that the coolant at the radiator will be a lower temperature than at the sensor closer to the engine.)
- Buy a hydrometer and test your coolant or take it to a Jiffy Lube, where they will probably do it for free! (Maybe you do this first, if you really feel like things are boiling.)
- Check the siphon on your overflow tank and make sure everything flows properly (and does not leak) between your tank and the radiator.
- Check your water pump and thermostat gaskets.
- Find religion and then explore your head gaskets.

Originally Posted by LS6427

HOLY **** man!!!!! Your over flow tank is FULL. You MUST use water with your coolant.

If those are air bubbles I'm seeing there it looks like you have a blown head gasket.

Or....that radiator cap is just shot. New or not. Its not working.

White smoke will NOT always come out the exhaust when you have a blown head gasket.

Does the level of that over flow ever go down?


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Originally Posted by raysadude

it only does that if the radiator makes the gurgling sound, which led me to believe there's probably some air in the system that pushes the coolant to the expansion tank. after it's cooling down the lvl of coolant will return to normal (not overflowing in expansion tank, and if i check it with the dipstick it'll display full)

man i hope it's not blown HG, because it never happened before, it just happened recently after i change my alternator, take off all the belts, waterpump, and put em back together again..i probably did something wrong whenever i reinstalled them back.

Originally Posted by LS6427

Might want to check a new radiator cap first.....but then I think it might be time for a leakdown check to see if the head gaskets are ok.

So, in the video you showed where the coolant was at the top of the neck of the over flow tank...does that level drop down when it cools? Or is the coolant always at the top of the over flow neck?

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Originally Posted by raysadude

ya when the car cools down the coolant would not at the top of the neck of the overflow tank. it actually never at the top of the overflow tank except if it makes the gurgling sound, and the temp slightly above 210

is there any performance related issue if your HG is shot?

coz my car would pull strong, as a matter of fact i just had it dynoed and it makes 346 rwhp

Originally Posted by LS6427

Well, you're the first person with a car like ours that has coolant flowing back into the radiator when it cools. Mine doesn't do that. Maybe my radiator cap is just too tight. I think you need to get another radiator cap just to see if that helps.

As far as the blown HG, the engien will perform normally.

In addition to getting a new radiator cap and trying it out. You need to remove your t-stat and bolt the housing back up (3 minute job). Start it up and top off the coolant with water. And go drive the car. See if the over heating issue and the gurgling stops. If it does stop you had an air bubble in the system.

If it still over heats you almost definitely have a blown head gasket.

Do those two things, otherwise your chasing your tail.

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Originally Posted by raysadude

thanks for the advice man!

i'll try to get a new cap tomorrow, so basically a blown HG wouldn't affect performance at all? wow i didn't know that, and my car wouldn't overheat it'd stay hovering around 180-220 if i turn on the A/C it'd be alot cooler

Originally Posted by raysadude

FYI i never mix water with coolant, should i mix the coolant with water?

Originally Posted by 99RTA

You are either low on coolant and have a small leak or the rad cap is bad. NOWAY it should boil when you shut it down, my 99 did that when the water pump gaskets started leaking. The boiling when shutting off tipped me off that something was up.

I don't care what anyone tells you boiling after shutting off is NOT normal!