Help! Coolant boiling...overheating

Hello everyone, im new to these forums. I have done a search and found a few things with my current problem, but cannot find a solution. My wife has a 98 cavalier 2.4 and recently has been overheating. there are about 120k miles on it. First I flushed the system then filled it with 50/50 dexcool. Then I found where there was a leak. I found the leak at the heater control valve (where there thermo for coolant temp housing) which i replaced a few days ago. Now the coolant is boiling in the recovery tank. I check my oil and its clean (no milky white junk) and i check the cylinders. there is no orange,greenish buildup on the sparkplugs of the cylinder walls. I cannot find that darn bleedvalve thats in my chaltons book and i am hoping this is the problem. So far what I have come down to is either 1)air in the system 2) bad thermostat (which aint going to be fun to get to) 3) bad water pump.
As for the bad water pump, people have said to see if my recovery tank has a swirling motion in it when the thermo opens, but i have not seen this. also I have read that the pump will not work if the system is not pressurized. any help or checks i can do will be greatly appreciated. I can already tell from alot of other posts that these cars all have cooling system problems.

All,

I have a 97, 2.2l, 5-spd with pretty much the same problem. I add water and then a few days later, I get a low coolant level light. Okay, I checked the oil to make sure it isn't getting mixed with the water and it is clear. (see previous posts about head gasket change) My question is, where is the water going? I am not seeing any liquids under the car, nor any steam while stopped.

What is the easiest way to test to see if the radiator is failing/failed?

thanks in advance....bighead

Hello everyone, im new to these forums. I have done a search and found a few things with my current problem, but cannot find a solution. My wife has a 98 cavalier 2.4 and recently has been overheating. there are about 120k miles on it. First I flushed the system then filled it with 50/50 dexcool. Then I found where there was a leak. I found the leak at the heater control valve (where there thermo for coolant temp housing) which i replaced a few days ago. Now the coolant is boiling in the recovery tank. I check my oil and its clean (no milky white junk) and i check the cylinders. there is no orange,greenish buildup on the sparkplugs of the cylinder walls. I cannot find that darn bleedvalve thats in my chaltons book and i am hoping this is the problem. So far what I have come down to is either 1)air in the system 2) bad thermostat (which aint going to be fun to get to) 3) bad water pump.
As for the bad water pump, people have said to see if my recovery tank has a swirling motion in it when the thermo opens, but i have not seen this. also I have read that the pump will not work if the system is not pressurized. any help or checks i can do will be greatly appreciated. I can already tell from alot of other posts that these cars all have cooling system problems.
When you say boiling do you mean steam is coming out of it ,if not try a new cap and make sure its the correct pressure rating for your car.

Sounds like a thermostat problem to me.
Does you heater work? If not, the t-stat isn't opening.

All,

I have a 97, 2.2l,....
I am not seeing any liquids under the car, nor any steam while stopped.

What is the easiest way to test to see if the radiator is failing/failed?

thanks in advance....bighead

Any white smoke out of the tail pipe when car is at operating temp?
If you're losing water with no visible signs, you might have a bad head gasket.

The water is boiling out of the pressure cap. Its not steam its actually boiling coolant. I get a little white smoke when i first start the car in a cold morning, but after about 5 secs it goes away. The heater does work. at first I found a leak in my heater control valve and fixed that. then spent $20 buying that dexcrap to refill the coolant and after about a 30 min drive got the low coolant light on and heard a gurgling sound from under the hood. Pulled over and pop'd the hood. Saw coolant boiling out of the recovery tank. I then checked for any other type of leaks. My operating temp was at 195 like normal.

Today i jacked the car up and inspected the thermostat housing. i see coolant trails coming from it, so i am hoping i have a bad gasket there. I am going to replace that this week sometime and hope that fixes the problem. I cant afford to keep buying dexcrap and refilling the recovery tank, I cannot believe its $10/gal

no... i do not have any white smoke during start up/operation. I am going to replace the t-stat and see what happens...

sounds like the rad cap to me, but thats just me.

okay... i replaced the t-stat, seal, and coolant. I ran it to where the fan came on and let it cool. We'll see how it goes over the next few days.
thanks for all the help/suggestions. I used Napa brand products based upon a previous post. In fact, i had problems with other brands and used a Napa head Gasket and haven't had a single issue in a year...

Okay, this is very confusing. I put the new t-stat in, but now it runs warmer than before. I am not losing water anymore, but the temp gauge is higher than what it was before. what gives?

Okay, this is very confusing. I put the new t-stat in, but now it runs warmer than before. I am not losing water anymore, but the temp gauge is higher than what it was before. what gives?

Depends on what you mean by warmer. It may just be that your last Tstat was either a lower temp, or it didn't work, or your new Tstat is a higher temp than the previous.
Where's your gauge? In the normal operating zone (below the red mark, say 200 degrees or less?)

it is still within the "normal" range. Before the needle was straight up and down. Now, it leans a few more degrees to the right. Hell, I live in Hawaii, I could just yank it out and call it a day.

it is still within the "normal" range. Before the needle was straight up and down. Now, it leans a few more degrees to the right. Hell, I live in Hawaii, I could just yank it out and call it a day.

Perhaps you have air in your system that needs to be purged.
I just had the same problem with my daughter's '96 Sunfire (same as the Cavie) when I replaced the T-stat and a hose-with-a-hole-in-it today. The temp gauge would go right up to the warning (yellow) mark. Once I bled the system, the gauge dropped to the middle range (about 185 degrees)

Here's how to purge the system.
Follow the metal hose that comes out of the t-stat junction which heads off to the heater core. Somewhere on that metal tube will be a sticker warning "do not vent with engine running". This is the bleeder port. Get the engine up to operating temp, shut the engine off, open the bleeder until coolant runs out. Open the bleeder slowly to let air escape.

Mike...thanks for the tip... Although I thought I filled/bled the system properly., I will follow your steps and let you know.

Thanks,
Bighead

Well, I had this same problem not too long ago maybe 3 months at most. I had just taken the car on a road trip and about 3 days later it went stupid.

So what i did was replace the following...

1. Water pump
2. Thermostat
3. Gasket around there

Didn't solve problem lol... But atleast now there new parts

4 replaced cap on resevoir and guess what the 5.00 cap was the problem as it wasn't keeping pressure and was letting out steam but was clear and couldnt see it ..

So i would suggest do it my way but do it backwards..

( i have a 1998 Cavalier 2.2L Rs also )