I've had this issue for a while now, but I cant seem to correct it and it got worse last night. I finished the EWP install and verified its getting power etc. I removed the thermostat, filled up the engine block through the water pump housing, then reinstalled the thermostat and housing. I then opened the bleeder screw on the Tstat housing and began to fill through the radiator. As soon as the air quit coming out of the bleeder screw and coolant began to flow from it, I closed off the bleeder screw and continued to fill through the radiator until the level came up to the top. Once the level came to the top, i stopped filling and turned on the water pump. The coolant level would slowly drop little by little and I kept adding until it quit dropping. At this point, I turned on the motor to warm it up and watched the level. As the motor warmed up, the coolant level would rise until it came out of the top of the radiator causing me to shut the engine down. Within 30 seconds it had lowered back down. Every time I turned the engine back on it would slowly rise until it overflowed out of the top of the radiator. Thinking maybe it was a pressure issue, I put the radiator cap back on, and started it up. I bled the system again until coolant came out of the bleeder screws and let it idle. The temperature slowly raised and got to the edge of the red but not quite into red. I bled the system again and there was a considerable amount of air but I checked underneath the car and there were no leaks anywhere. I got back into the car to check the gauges and the needle was in the middle of the red. I instantly shut it down and when I do I hear liquid dripping profusely. I hop out of the car, walk around to the front and coolant had sprayed out from under the radiator cap and soaked everything.

Im not sure whats going on. There is no oil in the coolant and there is no coolant in the oil, no smoke coming from the trail pipes, no indication whatsoever that I have a blown head gasket. My next step is replacing the thermostat and radiator cap, but I'm at a loss if that doesn't correct the issue. the only oddity as while i was sitting next to the car, cussing it out vehemently, I head the reservoir gurgle/burb once, but it was a couple minutes after I had shut everything down already.

I'm at a loss, any ideas?

 

Are you keeping track of how much coolant you are putting into the engine? I believe the entire system is 16qts. What I'm wondering is if you are creating a huge air pocket by filling from the w/p housing and then the radiator since you are essentially filling the top and then bottom of the engine. I've only ever opened the bleeders and filled through the radiator.

 

Ill be trying again tonight and will simply fill through the radiator and see what happens.

 

Yep. Drain the block completely to start over. Keep the car on level ground. no need to jack up the front.

 

Most of the cars I've owned will get almost overheating hot, then burp and need a refill and be good from there. My Camaro though is super easy. I have a bleeder in the hose for the steam vents off the heads. I fill the block through the thermostat hole, and then fill the radiator until water comes out the bleeder. Get it warm, come back, and top off. This Camaro doesn't need to get hot to burp, but it also doesn't have a heater core so maybe that's part of it?

 

Well, problem not solved. Here is a video of the coolant in the radiator with the car running warm. Note how the level starts to rise after I turn on the motor.
https://www.youtube.com/watch?v=TmNi...ature=youtu.be

This is the interesting part. If i run the EWP with the car off and the radiator cap off, the system seems to bleed out and will get to a steady level. However, once I start the car up with the radiator cap off, the the coolant level rises to the point where it will pour out of the radiator neck. Once I shut it down, the coolant level instantly starts to drop back to its original starting point.

After doing this a few times, I decided to put the fill cap on to see what happens and I started getting steam around the area of the fill cap and within 2-3 minutes the Low Coolant light came on.

The car sat for over ten years and I did drain all the fluids, but maybe the radiator is super clogged up from sitting for so long. I wonder if it's so clogged up that the water pump is creating a cavitation like event and creating the air bubbles in the system? When I swapped out the low coolant sensor the entire area around the sensor was caked with brown crap and the sensor couldn't even be seen. I'm guessing the radiator might be the same but Im not sure if that would create the symptoms I'm experiencing.

Ill be hooking up a radiator pressure tester soon to see if I have a leak somewhere. Again though, no smoke from the exhaust, not oil in the coolant and no coolant in the oil.

 

I had been having this issue last summer, but IIRC it was just a huge bubble I wasn't bleeding properly. I solved it by parking the car with the nose inclined up(steep driveway) and bleeding as I normally would.