Bleeding after heatercore replacement

[dodgethis]

Hello Everyone! I have replaced my heater core about 3 months ago, and didn't properly bleed the cooling system. Well since we are entering the fall/winter season, I need the heat. I have read a lot of threads on the forum about how to bleed the system. I have tried bleeding the car while it was parked on an incline. While having the radiator cap off, and bleeders shut I have squeezed the hoses, and have seen bubbles come out. After replacing the cap, I have opened each bleeder. I am still hearing bubbles in the heater core, and don't have any heat. I have done this for at least an hour, and after topping it back off with coolant.

 

When I reinstalled the heater core, I did use a funel and filled the core with coolant before I hooked it back up. Any thoughts or suggestions would be great as it is getting cold during the evenings!

 

Am I missing the correct steps to bleed on the 3100?

 

1) Park car on incline

 

2) Open radiator cap, check fluid level top off

 

3) start car, wait for operating temperature at which fans kick on, and open one bleeder valve at a time (I start with the bleeder on the water pump side), and squeeze upper radiator hose, before closing bleeder hold hose tight and then re-tighten bleeder valve

 

4) close bleeder on water pump side, and open bleeder on the thermostat side, and squeeze lower radiator hose.

 

5) replace cap after defeat, and fill fluid after engine cools.

[dodgethis]

I think I am going to do a complete flush of the cooling system, and see if i can get restore heat from the heater core. Has anyone removed the block plugs in order to do a thorough coolant flush?

[dodgethis]

I found it. The engine block drain can be found in front of the engine between the starter and oil filter. The rear block drain is located near the crank sensor

[55trucker]

Doing a *complete* flush of the entire cooling system shouldn't be necessary to solve your problem there.

 

To properly *bleed* the system........you don't need to park on an incline,

 

fill the system thru the rap cap to approx 2" below the filler neck, with the cap off let the engine run until the engine comes up to near running temp (as the temp comes up the fluid & air will expand), as the thermostat opens there should be a drop in the fluid level at the cap, when you see the fluid level drop refill to the top of the filler neck (the engine is still running). Now close the cap to seal the system, let the pressure build up and then open both of the bleeders just enough to get a forceful shot of air/fluid flowing from them (it will be white/foamy). When the flow begins to subside close the bleeders and let the pressure build up again, repeat the procedure with the bleeders....eventually you will see less foam & more coolant/anitfreeze, repeat this until you see no foam or tiny air bubbles when you open the bleeders. Shut off the engine, carefully open the rad cap (rag over your hand) to check the fluid level & top up again, close the cap, repeat the bleed process, when you get no air from the bleeders fill the overflow tank & you're done. This process can take as long as an hour so be patient.

Edited October 20, 2014 by 55trucker

[pitzel]

Woah, are you even sure that its a true "heater core" coolant problem, as opposed to something else? Bleeding is pretty idiot-proof. Open the bleeder screws (but don't totally remove, or else you'll run the risk of misplacing them), start the engine, and run until coolant appears at the screws. Close screws when this happens.

 

"Something else" could be related to the blend door itself (as was the case in my car), the actuator/controller (which, being an electronic gadget, can be seized), the head unit, etc. If you have one of those IR thermometers, or even with your hands, very carefully touch the coolant return line on the bottom left-hand side of the engine bay -- if its hot, then there's coolant flow, and you do not have a blocked/air-locked heater core.

 

And like seriously, a flush/drain? What is that going to accomplish? Is there any reason why the heater core might be blocked? Surely, you didn't put any stuff like stop leak or other heater-core-clogging crap in it, did you?

[dodgethis]

Woah, are you even sure that its a true "heater core" coolant problem, as opposed to something else? Bleeding is pretty idiot-proof. Open the bleeder screws (but don't totally remove, or else you'll run the risk of misplacing them), start the engine, and run until coolant appears at the screws. Close screws when this happens.

 

"Something else" could be related to the blend door itself (as was the case in my car), the actuator/controller (which, being an electronic gadget, can be seized), the head unit, etc. If you have one of those IR thermometers, or even with your hands, very carefully touch the coolant return line on the bottom left-hand side of the engine bay -- if its hot, then there's coolant flow, and you do not have a blocked/air-locked heater core.

 

And like seriously, a flush/drain? What is that going to accomplish? Is there any reason why the heater core might be blocked? Surely, you didn't put any stuff like stop leak or other heater-core-clogging crap in it, did you?

 

I have checked the coolant return line on the bottom left hand side of the engine, and it was hot. It was hot enough that I needed a shop rag to put over the hose in order to squeeze. I thought a flush/drain would help as I have introduced tap water into the cooling system ( I had used distilled water when I last did a drain, and fill) It has been a while since I have done it, and thought why not?

 

If the heater core is blocked this would be the first time I have experienced it. I thought it would be locked with air, as I hear bubbles when I first start the car, and it can be heard from the heater core, and would be reason why I have no heat. I have never put any stop leak into the cooling system.

 

I'll unhook both hoses going to the heater core, and see if its blocked by using compressed air.

[dodgethis]

Doing a *complete* flush of the entire cooling system shouldn't be necessary to solve your problem there.

 

To properly *bleed* the system........you don't need to park on an incline,

 

fill the system thru the rap cap to approx 2" below the filler neck, with the cap off let the engine run until the engine comes up to near running temp (as the temp comes up the fluid & air will expand), as the thermostat opens there should be a drop in the fluid level at the cap, when you see the fluid level drop refill to the top of the filler neck (the engine is still running). Now close the cap to seal the system, let the pressure build up and then open both of the bleeders just enough to get a forceful shot of air/fluid flowing from them (it will be white/foamy). When the flow begins to subside close the bleeders and let the pressure build up again, repeat the procedure with the bleeders....eventually you will see less foam & more coolant/anitfreeze, repeat this until you see no foam or tiny air bubbles when you open the bleeders. Shut off the engine, carefully open the rad cap (rag over your hand) to check the fluid level & top up again, close the cap, repeat the bleed process, when you get no air from the bleeders fill the overflow tank & you're done. This process can take as long as an hour so be patient.

 

Thank you I'll give this a shot once I can find out if the heater core is stopped up or not.

[dodgethis]

Well I just checked the car when I recently stopped by the store. The two hoses going to the heater core were hot. When I removed the older heater core, the plastic cover that goes over the core has two plastic feet to add support over the core. I cut those supports off as it was becoming a task to replace the cover. I seriously doubt that would have any affect as to why I lack heat.

 

Possible thermostat failure?

Edited October 21, 2014 by dodgethis

[Schurkey]

Well I just checked the car when I recently stopped by the store. The two hoses going to the heater core were hot. When I removed the older heater core, the plastic cover that goes over the core has two plastic feet to add support over the core. I cut those supports off as it was becoming a task to replace the cover. I seriously doubt that would have any affect as to why I lack heat.

 

Possible thermostat failure?

What is the coolant temperature sensor saying the engine is running at? Dash gauge still in the normal operating area?

[LA1]

I have not replaced the heater core I have pulled both hoses off and reattached later, filled with distilled water and coolant did the bleed as outlined in the manual. try squeezing the return hose when its been sitting overnight or all day then drive for 45 minutes with the heat on, then squeeze the return hose again, i'll bet you can feel pressure. you can always disconnect both hoses and rig up your garden hose with scrap hose and run water through the heater core to prove its not blocked.

Edited October 24, 2014 by LA1

[dodgethis]

I have not replaced the heater core I have pulled both hoses off and reattached later, filled with distilled water and coolant did the bleed as outlined in the manual. try squeezing the return hose when its been sitting overnight or all day then drive for 45 minutes with the heat on, then squeeze the return hose again, i'll bet you can feel pressure. you can always disconnect both hoses and rig up your garden hose with scrap hose and run water through the heater core to prove its not blocked.

 

Good point. I'll report back what I find

[dodgethis]

What is the coolant temperature sensor saying the engine is running at? Dash gauge still in the normal operating area?

 

Dash guage has sat around the middle once the fans turn on. I could get actual readings through freeze frame data if I threw a engine code. As of now there isn't a light on.