Need help with burping cooling system
 

I have been burping the coolant system on my 86 N/A for the past 2 days but have been running into some issues. I used a no spill funnel, jacked the car up, massaged the hoses, and had the heat on while burping. Took it for 2 drives yesterday. First one was perfect, no problems. Second time, the coolant buzzer came on when I was a mile away from my house. Attempting to burp again and now the buzzer came on within 30 minutes. However, temps do not go above half. What's confusing me is why the coolant level in my funnel rose when it buzzed but fell back down after the car was off for a while. I bought brand new koyorad, coolant temp sensor, thermostat, and hoses. Have no clue what the issue is at this point.

Pictures
 

https://cimg2.ibsrv.net/gimg/www.rx7...996a1f616a.jpg
Car got to operating temp, then buzzing.
https://cimg5.ibsrv.net/gimg/www.rx7...bbdf831ced.jpg
After shutting the car down for 10 minutes. Where I originally poured.

By the way, the thermostat was Mazda OEM from AtkinsRotary.

did you try leaving it overnight with the funnel in?

No, I have not tried that. However, when I checked the level this morning before the funnel, it was fine.

Did you open the bleeder on the radiator? If not, there's likely a big air bubble in there

Yes, I opened the bleeder screw while i was adding coolant.

-Edit-

Two questions:

Is the servo above the gas pedal opening the heater valve? (You should be able to hear it whirr when you move the temperature selector.)

Is the fast idle thermowax on the throttle body getting coolant? They like to get clogged. (Fastest way to tell is if the idle drops to 750rpm as the engine warms up.) If coolant can't circulate, you can't get all the air out.

- Also check the overflow tube and rad cap for leaks. They can both draw air in as the engine cools.

I second the water line that goes to the fast idle themrowax. Mine was so full of gunk, edges were corroded and other crap, and it became part of the burping process, let car get to temp, crack that line open while keeping that large funnel in place so funnel was highest coolant point, and push the air out of that line.

Also make sure the car heat is on, and fan is on, the logicon closes a valve in the heatercore that prohibits water flow. if there is an air bubble in there, it returns to the cooling system after the radiator and before thw water pump, so it could just get recirculated

I also would jack the car up to as much angle on each side, for example, drivers side would cause those air bubbles in the heater core to make their way into the radiator, and then passenger side to get the air bubble to the bleeder screw.

Blow air into the overflow coolant tank, to push water back up the overflow line, so it is not sucking air back in when the car cools.

Two of the modifications I have to my car have made this tons easier, I have a radiator that has a cap, so I have two fill ports, and also overflow ports, I just have a metal T that goes to the overflow tank, that that then splits to each, same process, blow air to pressurize the tank and force water up the line so no air is in it. Other modification is a Megasquirt ECU, so the themowax is completely removed, and do not have to do that bullshit burping on that line anymore.

Been busy and forgot to reply. I have been repeating the burping process and it seems to have gotten the issue resolved. I may still check that thermowax line when I get a chance. Otherwise, car has been fine. I also was unaware that the buzzer happens in regards to oil pressure.

The buzzer should be paired with a light on the center dash cluster of what is wrong. Oil fill or coolant. Do all those lights light up as a function check when you start the car?

I would see the "add coolant" light prior to my extra bleeding sessions. Never seen an oil light but sometimes the buzzer would randomly happpen without any lights.

[QUOTE=DaBrkddy;12580688]-Edit-


Is the fast idle thermowax on the throttle body getting coolant? They like to get clogged. (Fastest way to tell is if the idle drops to 750rpm as the engine warms up.) If coolant can't circulate, you can't get all the air out.

Yes, my idle drops to 750 rpm. Last night the car overheated and the coolant oclverflowed out of the reservoir. So now I'm under the impression that the thermowax may indeed be clogged.

Would you be able to show me where the thermowax line is? I'm assuming its the line at the top of the first image with the clamp? Also, how would I unblock it?
https://cimg4.ibsrv.net/gimg/www.rx7...7b5c6a40ee.jpg
https://cimg9.ibsrv.net/gimg/www.rx7...257a0d6ea4.jpg

Tell me something, does your radiator over fill bottle get filled to the top over time? . . . . .Do you see leakage from the vent tube on the overfill bottle?

in any case, change the sensor on top of the radiator and clean the contacts on the connection plug .. .This sensor is like 12 bucks on amazon.

I have used this port to burp the system before. . . .. .I had a situation in the past where the sensor and connection were bad and the warning cluster would give a false alarm.

It usually stays in between the low and high marks. Sensor at the top of the radiator is brand new. I will try cleaning the contacts but I'm pretty sure the thermowax lines are blocked. Last time I drove it, it overheated out the reservoir. Since the temps in my area are back above 30 degrees, I will do some troubleshooting tomorrow.

Ok, just blew air into the upper thermowax hose and coolant instantly shot out. Hoses were also clean on the inside so no blockage right? I honestly don't know what else could be the issue. I guess I will burp it again while bleeding from the hose like Malic suggested.

Car was running for about 20 minutes until I shut it off. All of a sudden my idle is at 2k rpm now.

Assuming your water pump is working, overheating can be caused by a bad radiator or bad cooling fan clutch.. . Not much else assuming the water is full and the correct radiator cap is used.

If you can, do a pressure check on the cooling system to ensure no issues there.

I would change the water temp sensor behind the alternator just because it is so cheap and it effects cold starting and startup idle.. . .Although it has nothing to do with overheating.

I would do the idle set procedure per the manual assuming the over heating issue is solved.

https://www.foxed.ca/rx7manual/manuals/1988FSM/04a_FUEL_AND_EMISSION_CONTROL_SYSTEMS_NA.pdf

https://www.foxed.ca/rx7manual/manuals/1988FSM/03_COOLING_SYSTEM.pdf

@rlynchster radiator and fan clutch were replaced. Water pump isn't leeking from the weep hole so I'm assuming its in working condition. Car did good on the cooling pressure test from Mazcare here in GA.

I turned the car back on 40 minutes ago and idle was back to normal. Ive been letting air out the bleeder screw and thermowax line periodically. It SEEMS ok right now but it has been back and forth with this for weeks. Next on my list is to check my spark plugs after the car cools back down.

I also did this test :
No bubbles which is good

In summary, the first day or so after bleeding the coolant. The car runs perfect. However, after that period is when I would get the buzzer followed by higher temps. However, since replacing thermostat, radiator, sensors, rad hoses, radiator caps, and clutch fan, the car overheated from the reservoir recently. Today I inspected the lines going to the IAC through the thermowax for blocks and they all looked good. Also, no leaks from any of my lines.

Only other thing I can think of is a pinhole leak somewhere, do you have any way to pressurize the cooling system for air and then look around and squeeze and bend any hoses to see if they are spraying any water? No more then 30 psi, most higher pressure caps are in the 26 psi range

Super late update but I'm assuming it may be a burned coolant seal. I spoke with some members of the "ATL RX7s" group on Instagram. My symptoms seemed synonymous with another member who had burned seals due to warped housings. Under pressure, there are no coolant leaks. However, it seems to seep into the combustion pocket and create an air pocket on the next startup.

I had a coolant pressure test performed by Mazcare in August of last year and it held pressure. However, I'm currently trying to find someone to perform a combustion leak test for me. I spoke with Mazcare and they no longer have the equipment to do so. I want to be sure this is the issue before I start to look into rebuilds.

It would be greatly appreciated if anyone could point me in the direction of someone to perform the leak test as well as some reputable rebuild shops near Georgia. So far, all I got was Rotary Resurrection in Morristown, TN.