Overheating, puking coolant out the overflow

Hey all

99 GA se 2.4 auto

I recently traded a ranger for this GA and have had problems ever since. First it was a p0507 high idle code accompanied by high idle and surging and lunging when i let off the gas. I replaced the iac, tps and tested the map or maf sensors. I couldnt figure it out so I put it in the shop and they replaced the plenum and intake gaskets. After the shop, the problem smoothed out and its no longer doing it but the SES light is still on. At least it is running alright now.

And now...if that wasn't enough lol I have a coolant puking problem. The car normally runs at 200 degrees. Lately, when i shut the car off and get out there's a green puddle under the car. I can drive it and the temp now reaches 215, shut the car off and its spewing about a gallon of coolant out of the overflow. Put more in to the hot mark and run it, shut it off and its the same problem. Heres the thing, the hoses are all hot and i dont think the fans are kicking on. I checked the fuses for the fan and there all ok. I did not check the relays for the fans cause i am not sure how. Or maybe i am barking up the wrong tree with the fans and relays i dont know.

All i know is that its puking coolant when i shut the car off and the temp needle is just over halfway to the red...not much higher than normal temp for it and the temp needle is running slightly higher than normal.

any ideas?

one thing i forgot to mention is that its getting boiling hot. the coolant has long since been replaced by water with all the puking out the overflow. but even the coolant was getting boiling hot.

Do you have A/C?

If so, putting the A/C on will turn on the fans, easy way to test it.
If not, then just let the car heat up and pop on the hood and look at them.

It can be one of 2 things. 1 your thermostat is stuck closed. 2 a blown head gasket. To check to see if the head gasket is bad, start the car and check the radiator hose, if it get hard before the car warms up. It is the head gasket. If it does not it is the thermostat that is stuck closed.

one thing i forgot to mention is that its getting boiling hot. the coolant has long since been replaced by water with all the puking out the overflow. but even the coolant was getting boiling hot.
If you just have water in there, it will boil to steam and push itself out. Coolant is supposed to not boil at normal operating temperatures.

I've been having the same problem on my 2002 gt. I just split open my second coolant recovery tank at the seam. My question is if the thermostat is sticking closed, wouldn't the car overheat? I have no coolant in the oil or oil in the coolant, the temp gage is normal and my heat works good. I sure hope it's not a head gasket, I just did the intake gaskets...

The thermostat open at about 88C
The fan start at low speed at 106C
And is at high speed at 110C


If you have plain water, IT WILL BOIL, and will also do long term damage to the engine and radiator.

I'ld check if you have bubbles comming out of the system before it boil. If so you have a broken head gasket.

I'ld turn on the A/C and see if the fan work (it will automatically turn them on when A/C work). If so, see if you can drive with A/C on.

If it still boil, check your thermostat...

if it still boil... head gasket or water pump or plugged radiator or something

- check your coolant level when engine is cold and do it at night with the flash light between the tank and fender. Then you will be able to see the exact amount of coolant in there. Do not overfill, or once coolant heats up it will start to expand and will have no where to go, and will create even more pressure. Also replace you tank cap since after years and years of opening and closing will cause the rubber seal to get worse and worse and it will start to leak. Also do not buy cheap coolant reservoirs that are like 33$ brand new or they will start to leak at the seam. My started to leak after only 20 days and I noticed that other people had the same problems. If you see made in China then stay away from it. I recently posted diagram how to wire your cooling fan so that every time when you press brake pedal the fan will come on. This improvement helped my GA a lot. Coolant temp will never cross 1/2 mark trust me.

- check your coolant level when engine is cold and do it at night with the flash light between the tank and fender. Then you will be able to see the exact amount of coolant in there. Do not overfill, or once coolant heats up it will start to expand and will have no where to go, and will create even more pressure. Also replace you tank cap since after years and years of opening and closing will cause the rubber seal to get worse and worse and it will start to leak. Also do not buy cheap coolant reservoirs that are like 33$ brand new or they will start to leak at the seam. My started to leak after only 20 days and I noticed that other people had the same problems. If you see made in China then stay away from it. I recently posted diagram how to wire your cooling fan so that every time when you press brake pedal the fan will come on. This improvement helped my GA a lot. Coolant temp will never cross 1/2 mark trust me.

Oreilly, Autozone, and Advance all sell Dorman Brand resevoirs. I bought my last one from Napa and it's a different brand but everything looks exactly like the Dorman. I'm beginning to think that there's only one manufacturer for these resevoirs. I guess my next bet is to buy one straight from the GM SPO warehouse..