Heater bubbles under dash not going away

[NiGMa]

Hi folks,

So, I followed the instructions on the SOGI tech tip page "Removing Trapped Air from Cooling System" but havent seen the results, I was parked on a steep hill for 30mins running the engine with the radiator cap off, acutally, to stop the coolant/water pilling everywhere I attached a spare radiator hose to the cap neck, but I dont think this would of affected anything.

What is best to try next? whats more likely? Its definately not BHG because I did that about 2 years ago and so am running a new motor with a metal HG, and it hasn't overheated, so I dont think any air would be getting in through there. what now?

Thanks guys =) let me know if you need more details, oh 7M-GE 1986.5 Australian made

NiGMa

 

[NiGMa]

did some reading in this thread... I definately want to get a cooling system pressure tester next.

http://www.supramania.com/forums/showthread.php?t=23966&page=5&highlight=waterfall

 

[Z'mnypit]

Yeah, Id check that next if you done everything right the 1st time. It took mine about 10 min and all the bubbles were gone.

 

[Shytheed Dumas]

I think I ran mine for 40 - 45 minutes to completely burp the system. You definitely have a leak somewhere to allow air in, so the pressure tester's a good idea. The last time I had to deal with it was due to a loose hose clamp that was really hard to get to - until the engine was out for my tranny swap, that is.

 

[SupraMario]

I can't remember who posted it but it was someone with some crediblity on these boards, that said, burping the car is useless, the engine was designed to get rid of the air bubbles itself.
Don't take my word for it thought, but I remember a bunch of threads like this and that being posted in one. Made sense to me, air escapes from the overflow and sucks in coolant without air in it.

 

[Rajunz]

Go buy a FRAM fill kit and mount the tee in the the heater hose up at the firewall. Fill the system from this tee with the cap off and the engine idling, once it overflows the radiator, replace the cap, shut the car off and finish filling the lines to the tee and cap off the tee. That will remove all of the air in the system.

 

[NiGMa]

Thanks for all the suggestions and comments guys, heres a question: Isn't it dangerous to put extra pressure through the cooling system with a pressure tester? wouldnt I risk blowing a hole in the head gasket? or is that just totally no way near the pressure required to threaten it?

Thanks

 

[SupraMario]

Thanks for all the suggestions and comments guys, heres a question: Isn't it dangerous to put extra pressure through the cooling system with a pressure tester? wouldnt I risk blowing a hole in the head gasket? or is that just totally no way near the pressure required to threaten it?

Thanks

Only so much pressure can build in the system, if it becomes to high, it dumps it into the over flow bottle, and if that fills up, it drains it out the top of the over flow bottle. AKA your car is puking, and either has a blockage somewhere or it was over filled.

 

[NiGMa]

Only so much pressure can build in the system, if it becomes to high, it dumps it into the over flow bottle, and if that fills up, it drains it out the top of the over flow bottle. AKA your car is puking, and either has a blockage somewhere or it was over filled.

Ahh, thats it, thanks. I did this the other day while I was on the hill, the overflow was full too and a nice steady stream of water was flowing out the hose that continues past the cap. I like to know what enables the water to flow into the overflow, are there some pressurised valves in the piping to the overflow bottle?

Also, its been suggested by some on other threads to drill a hole into the thermostat housing which should let any trapped air escape as you drive. I dont see how this would work as there is so much pressure in the cooling system when the engine is running, thats why I open the radiator cap less than 20min after driving. wouldnt the coolant just be spewing out of the drilled hole? or am I missing something?

check mrnickleye's post in this thread: http://www.supramania.com/forums/showthread.php?t=26168&highlight=drill+waterfall

Thanks again guys

NiGMa

 

[CSquared]

Ahh, thats it, thanks. I did this the other day while I was on the hill, the overflow was full too and a nice steady stream of water was flowing out the hose that continues past the cap. I like to know what enables the water to flow into the overflow, are there some pressurised valves in the piping to the overflow bottle?

Also, its been suggested by some on other threads to drill a hole into the thermostat housing which should let any trapped air escape as you drive. I dont see how this would work as there is so much pressure in the cooling system when the engine is running, thats why I open the radiator cap less than 20min after driving. wouldnt the coolant just be spewing out of the drilled hole? or am I missing something?

check mrnickleye's post in this thread: http://www.supramania.com/forums/showthread.php?t=26168&highlight=drill+waterfall

Thanks again guys

NiGMa

The coolant runs back to the overflow via the hose that runs from just under the cap on the radiator back to the cap on the overflow.

You shouldn't need to do anything further than putting the car on a steep hill, or some jack stands, removing the radiator cap, and letting the car run for a few minutes. I usually do that and let the car run for about 15-20 min with the heat on full blast. To be sure, I'll also squeeze the upper rad hose a few times towards the end to get rid of any air pockets that may be sitting towards the top... and occassionally rev the engine.

Honestly I had this problem a few years ago... First time this started happening, I'd burp the system and it would be ok for a few days, then start the waterfall sounds again. In that instance, I had a very SLIGHT blown headgasket that a block tester couldn't even catch. Eventually blew completely.

Afterwards the car started making noises again and honestly i don't know for sure, but i think some air was getting trapped up in the heater core. For a while i blocked it off, burped the system, and didn't have any more problems. Now I hooked everything back up, and like i said, i just burp the system with the heat on, and i haven't had any recent trouble.

P.s. Make sure your rad cap is sealing properly, there are no leaks, and you have enough coolant in the overflow.

 

[Paradox]

i have the same problem. burp it again and check for leaks.. i think my heater core might have a leak cause i have to burp the system about once every 2 months. other than that, new t-stat always helps and flush out your system and replace all fluids.

 

[jdub]

P.s. Make sure your rad cap is sealing properly, there are no leaks, and you have enough coolant in the overflow.

Do this ^^^
And a pressure test.

Drilling the hole is on the thermostat itself, not the housing. You cut the jiggle valve off and can drill the hole a bit bigger (1/8" or 3mm) if you wish. Make sure the hole is at the top when installed. This allows a constant, small amount of coolant flow to the radiator...less pressure build-up behind the stat.