Rampage Posted January 26, 2021 Share Posted January 26, 2021 What happens from a slow leak or bad radiator cap is it lowers the pressure in the system and that lowers the boiling point of the coolant allowing it to boil and create air bubbles. 1 Link to comment Share on other sites More sharing options...
idosubaru Posted January 26, 2021 Share Posted January 26, 2021 (edited) Headgasket or slow leak - check the coolant cross over and heater core hoses - the metal ones. They rust and leak. I would guess you have a good chance of it being a rubber hose or one of the metal lines leaking. They can leak intermittently due to the rusty scale not leaving an actual hole but the coolant migrating through the layers based on various ambient conditions. This makes them tough to find sometimes But if they’re rusty that Should be obvious have you noticied any coolant smells? Hopefully you get lucky but this is how some H6 headgaskets begin to show themselves. Random events spaced months apart. It’ll slowly get worse over time so you’ve got a looong time to wait and see and check other things if it is the HG. Can take months, up to a year to manifest itself to obvious symptoms. I say this because the heater core being clogged isn’t likely to be that intermittent and that “hot/cold”. They’re often “warm” or even vary drivers to passengers side. And manifested itself with different symptoms each time - the second being overheating. You had low coolant in the radiator - it should have drawn water from the overflow. Thermostat doesn’t cause low radiator or heater core issues or coolant loss. you bought a pressure tester last summer as if something was suspected? H6 headgaskets have this kind of “timing”, months apart, more than other options. A slow leak or HG explains all of those for H6 Subarus. Nothing else really does A leak is more likely but watch that temp gauge. It is 100% not the water pump unless it’s the source of your water leak. There’s a weep hold on the drivers side - look there for water pump leak. Rare on H6s but it happens. If it’s not leaking then the water pump is fine. Edited January 26, 2021 by idosubaru 1 Link to comment Share on other sites More sharing options...
heartless Posted January 27, 2021 Author Share Posted January 27, 2021 17 hours ago, idosubaru said: Headgasket or slow leak - check the coolant cross over and heater core hoses - the metal ones. They rust and leak. I would guess you have a good chance of it being a rubber hose or one of the metal lines leaking. They can leak intermittently due to the rusty scale not leaving an actual hole but the coolant migrating through the layers based on various ambient conditions. This makes them tough to find sometimes But if they’re rusty that Should be obvious have you noticied any coolant smells? Hopefully you get lucky but this is how some H6 headgaskets begin to show themselves. Random events spaced months apart. It’ll slowly get worse over time so you’ve got a looong time to wait and see and check other things if it is the HG. Can take months, up to a year to manifest itself to obvious symptoms. I say this because the heater core being clogged isn’t likely to be that intermittent and that “hot/cold”. They’re often “warm” or even vary drivers to passengers side. And manifested itself with different symptoms each time - the second being overheating. You had low coolant in the radiator - it should have drawn water from the overflow. Thermostat doesn’t cause low radiator or heater core issues or coolant loss. you bought a pressure tester last summer as if something was suspected? H6 headgaskets have this kind of “timing”, months apart, more than other options. A slow leak or HG explains all of those for H6 Subarus. Nothing else really does A leak is more likely but watch that temp gauge. It is 100% not the water pump unless it’s the source of your water leak. There’s a weep hold on the drivers side - look there for water pump leak. Rare on H6s but it happens. If it’s not leaking then the water pump is fine. we have been down the rusty pipe road before with both my Forester and the 95 Legacy i had.. so yeah.. that is at the top of my list to look closer at. he has not said anything about smelling coolant, except for the other morning when left but then came back.. I don't think it is heater core, either.. just does not jive at all.. the heat is either working or it isn't, there is no in between, luke warm episode, and when it is working, it works quite well.. We did not "buy" the pressure tester - just rented it.. and it was because he was seeing steam occasionally from under the hood with some coolant loss.. at that time, it was a radiator hose that had a small split in it.. was not visible when just looking at it when cold, but there were obvious signs of liquid in the general area (staining).. put some pressure to it, and it opened up and sprayed a fine stream. cap was checked at the same time and tested fine (the one on my Forester was shot, tho) As for pulling coolant from the overflow bottle.. yeah - it should, if there is any in there for it to pull from.. the bottle was rather grimy and he was having a hard time seeing if there was anything in it.. I made him take the bottle off and I cleaned it so it is now easy to see. Really hoping it is just a bad water tube or a hose to be honest.. really don't relish the thought of head gaskets.. i know it is not super common on the H6, but it does happen.. Link to comment Share on other sites More sharing options...
idosubaru Posted January 27, 2021 Share Posted January 27, 2021 A leak can also cause it to not pull from the overflow. Leaks and there becomes more and more air in the system which prevents the overflow system from working right. 2 Link to comment Share on other sites More sharing options...
heartless Posted February 9, 2021 Author Share Posted February 9, 2021 Update #2 - Feb 9, 2021 Well, we are back to no heat again - but this time coolant level is spot on and has been since he changed that radiator hose last time. Subzero temps the last few days... -9F currently as i type this. Yesterday (ever so slightly warmer) he had no heat initially, but after fiddling with it a bit he got it to work. Today, he has taken my car since the heat in his would not come back. So what are the chances that this is a problem with the control unit itself? Seems that the extreme cold exacerbates the issue (cold contracts) - thinking possibly bad solder joints somewhere? Link to comment Share on other sites More sharing options...
idosubaru Posted February 9, 2021 Share Posted February 9, 2021 No heat as a stand alone symptom points to control unit or clogged heater core. Those 06 controls are a bit convoluted. Are both heater core hoses in the engine bay hot? Are the control unit functions all working properly - display, temps, and does it properly change from feet to vent to defrost airflow positions, etc...? Can you hear the blend door moving when you switch HVAC output positions. Some 06+ era Subaru’s would have lack of heat due to internal coatings clogging the heater core. It may have only been Tribecas but it’s worth looking into. The solution is to flush the heater core or replace it. 1 Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted February 9, 2021 Share Posted February 9, 2021 yeah, is the heat being misdirected to the windshield? Link to comment Share on other sites More sharing options...
heartless Posted February 9, 2021 Author Share Posted February 9, 2021 5 hours ago, idosubaru said: No heat as a stand alone symptom points to control unit or clogged heater core. Those 06 controls are a bit convoluted. Are both heater core hoses in the engine bay hot? Are the control unit functions all working properly - display, temps, and does it properly change from feet to vent to defrost airflow positions, etc...? Can you hear the blend door moving when you switch HVAC output positions. Some 06+ era Subaru’s would have lack of heat due to internal coatings clogging the heater core. It may have only been Tribecas but it’s worth looking into. The solution is to flush the heater core or replace it. As far as I can tell, yes, everything is functioning as it is supposed to - temp readouts are fine, directional controls all seem to work correctly, fan functions as it is supposed to on all speeds - just no heat when heat is called for. I could probably go out right now, having touched absolutely nothing, and it would work fine - temp has come up to 6 above now. In fact, just to confirm, i may go do just that. 5 hours ago, 1 Lucky Texan said: yeah, is the heat being misdirected to the windshield? No, Texan - there is NO heat at all when it does this - none - it blows COLD air, even when heat is being called for. All of this just reaffirms my belief that more electronics in cars is nothing but problems. Link to comment Share on other sites More sharing options...
heartless Posted February 9, 2021 Author Share Posted February 9, 2021 31 minutes ago, heartless said: Some 06+ era Subaru’s would have lack of heat due to internal coatings clogging the heater core if this is what was happening, it would not be an intermittent thing, would it? this is a very intermittent situation here.. comes and goes, and seems to be ambient temperature related. Link to comment Share on other sites More sharing options...
heartless Posted February 9, 2021 Author Share Posted February 9, 2021 ok, just tested this theory of the ambient temps being a major part of the problem here... was -9 this morning when no heat now 6 above - a difference of 15 degrees - and the heat is working fine. i did nothing other than start the car and let it warm up.. Link to comment Share on other sites More sharing options...
heartless Posted February 9, 2021 Author Share Posted February 9, 2021 and just so there are no questions about which system he has.. these are the controls Link to comment Share on other sites More sharing options...
Numbchux Posted February 9, 2021 Share Posted February 9, 2021 On 12/29/2020 at 9:50 AM, Numbchux said: heater hoses. On 12/29/2020 at 1:00 PM, Rampage said: heater hoses On 12/29/2020 at 6:54 PM, Rampage said: heater core hoses 7 hours ago, idosubaru said: heater core hoses ... Need to sort out if it's a coolant flow issue, or an airflow issue. Link to comment Share on other sites More sharing options...
GeneralDisorder Posted February 9, 2021 Share Posted February 9, 2021 (edited) Most likely the control panel is developing cracked solder joints. Happens ALL the time on the 05 and 06 units. More prevalent in cold weather. Subaru had a reman program where you can send it in for repair. They are no longer available to purchase new (all have been sold due to control issues or radio malfunctions (also common). THE BEST solution, is to get the double DIN replacement JDM control panel so you can also have an aftermarket stereo. https://avojdm.com/dual-zone-av-panel-set-h6217ag911/ Try pressing on the dash, and also you can try power cycling with the battery terminals. We have seen quite a few of those have all kinds of random behavioral problems. GD Edited February 9, 2021 by GeneralDisorder 1 Link to comment Share on other sites More sharing options...
idosubaru Posted February 10, 2021 Share Posted February 10, 2021 (edited) 5 hours ago, heartless said: As far as I can tell, yes, everything is functioning as it is supposed to - temp readouts are fine, directional controls all seem to work correctly, fan functions as it is supposed to on all speeds - just no heat when heat is called for. I could probably go out right now, having touched absolutely nothing, and it would work fine - temp has come up to 6 above now. In fact, just to confirm, i may go do just that. No, Texan - there is NO heat at all when it does this - none - it blows COLD air, even when heat is being called for. All of this just reaffirms my belief that more electronics in cars is nothing but problems. checking heater hoses first would be a good data point just knowing you’ve got hot coolant on both sides. Correct - they can vary somewhat when they clog but it’s not as binary as you describe, waxes and wanes in intensity more than on/off and can even vary from passenger to drivers side. If yours is on and off variability then yeah that’s electronic and like I said I have only sent that on Tribecas. Yours sounds electronic as GD said and you guessed. One of my best friends has an 06 and immediately went to JDM and aftermarket option like GD said. He hates working on cars and figured it all out himself. So it should be easy. Edited February 10, 2021 by idosubaru Link to comment Share on other sites More sharing options...
GeneralDisorder Posted February 10, 2021 Share Posted February 10, 2021 We have had customers turn around and come immediately back after a head gasket replacement and complain that we "broke" their radio . Then we disconnect the battery, wait a few minutes, touch the terminals to each other to discharge caps, etc and like magic the radio works again. Then we have to explain to the customer how lucky they are that they will be getting a new stereo real soon and that it will only cost about $1000 with the JDM panel, a nice double DIN deck, and installation. GD Link to comment Share on other sites More sharing options...
heartless Posted February 10, 2021 Author Share Posted February 10, 2021 ok, so going to get the damn thing pulled out this weekend and get a good look at it.. I have a wearable magnifier to get a good look at things, and a good solder station an know how to use them, LOL GD - thank you for the link, i will pass it along to the other half - his choice on this one.. I know he looked at doing that in the past - not sure why he didnt. Link to comment Share on other sites More sharing options...
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