99 3.1 V6 coolant loss overflow tube

[MalibuMan99]

OK so I just recently bought a 1999 Chevy Malibu LS with the 3.1L V6 in it. The car has 150k miles on it and when i got the car it was showing a code for misfire on cylinder number 6, but it drove with a bit of a miss but drove none the less. On my way home when I bought the car I noticed it was overheating, so I called the guy I got it from and he said he didn't bleed the coolant system when he filled it last. So i stopped at a gas station and got some antifreeze and filled/bled the system. About 5 miles down the road it was overheating again, so another gas station and more antifreeze and more bleeding and on my way i went. So from that point I made it all the way home, another 18 miles, without over heating at all and even had hot air from my vents, though it was almost hot enough to literally burn the skin on your hand. Soon as I shut the car off in the driveway it blew most of my coolant right out the overflow. It continued to do this either while driving or after I would shut the car off everything I added fluid and bled the system. I replace the thermostat, no fix, water pump, no fix, flushed the radiator, and still no fix. I just replaced the front head and both head gaskets due to a bent exhaust valve on the number 6 cylinder. When I got everything put back together, filled the coolant system and bled it, I started the car and it ran really smooth. I was hoping not only had I fixed my misfire problem, but maybe I fixed my coolant loss problem too. No surprise when I pull out my driveway to take it for a test drive, that a mile down the road with the temperature gauge reading half way, I have no heat when I turn the head on full blast. I only went about 4 miles total round trip for the test drive and when getting back to my house I clearly see where I lost most of my coolant when originally leaving my house. People have told me it's a blown head gasket, but they are new. I've been told intake gasket but they are also new. I use a Chilton manual for most torque sequences and torque specs but I also called a dealership while I was putting the motor back together to verify all torque specs so i know the engine is together correctly. I'm so frustrated with this right now and I really need to figure out what the issue here is cause my wife needs this car while im at work so she has a way to get around with the kids, and I cant let her drive it like this knowing there may be something majorly wrong with it. I have no water or milky discoloration in my oil so i ruled out head gasket or cracked block leading water to oil or vise versa. I fill my expansion tank with the bleeder closed till it's full the open the bleeder and wait for water to come out. I then close off the bleeder, fill the tank till it's half full, run the car till it gets warm, then i shut the car off, open the bleeder and wait till water comes out again after it's pushed all the air out, I top off the expansion tank and put the lid on and almost everytime it blows the coolant out the overflow tube, except a few times it waits untill i get where im going and does it when i shut the car off. Does anyone have any idea what's causing my car to do this? I would really appreciate any suggestions or advice that anyone could give me that may solve my problem. Thanks - Bobby.

[jyount]

Goto NAPA and get a hydrocarbon sniffer for your coolant. Still sounds like heads or gaskets to me. Only way to introduce large amounts of pressure into the coolant before it overheats. You said it dumped a bunch right out of your driveway. A sniffer will tell you, you shouldn't have any hydrocarbons in your coolant. If you do You know what the deal is.
Heads, gaskets, or heaven forbid a block....

[MalibuMan99]

Well I didnt get around to trying that yet, but I let the car get to full operating temperature before it pushed out the coolant. It actually goes a line or 2 past the half way mark on the temperature gauge (not sure if it's supposed to go that far for normal operating temp) before the thermostat opens, and only seems to push the coolant out when im actually driving it. 3 times while refilling the system, after it got close to the red zone, and bleeding it and then going back on about my drives it has actually not pushed my coolant out and I actually have had heat. When this has happened I thought that it was finally fixed, but when I get where i'm going and turn the key off it will push the coolant out immediately. It seems like the car is overheating when this happens but my temp gauge doesn't go past maybe a line or two above half way mark.

[Bill60118]

I just flushed my radiator and replaced the hoses on my 2001 Malibu. I had the same problem of the overflow spitting antifreeze all over once I shut the engine off. This is what you need to do. Fill the overflow and start the car. When it reaches normal operating temp check to see if overflow is spitting. If not, rev the engine for a little bit while keeping an eye on the overflow tube. As soon as it begins burping antifreeze shut off car and open 7mm bleeder. Be careful not to burn yourself. I used a 7mm deep socket. You'll know when the bleeder is open enough because antifreeze will stop coming out of the overflow. Also while you have the bleeder open squeeze on the upper hose to move any air trapped in the system. You'll have to do this maybe 5 times or until all air is out. The final thing to do is fill overflow to level and drive car. When you return leave car running and open hood. Then shut car off and see if it still burping antifreeze. If it does then you still have air in the system somewhere.

As for not having any heat. Replace the thermostat. Pain in the butt to get to. At least on the '01 malibu it is.

[in need]

I have a 1999 Chevy Malibu. Runs great but then the temp gauge goes up and at same time heater stops blowing heat. Then heat starts blowing heat and temp drops back to normal! What is going on??

[aleekat]

If not head, gasket, block. Any chance the PO added a bunch of stopLeak crap to it?