: flushing heater core. Need help



catera00
11-10-07, 03:30 PM
I am trying to flush my heater core due to a no heat problem. THe dealer checked it out and said there isnt any coolant going through the heater core and recomended a flush for $250. I figured I could do it myself. I disconnected the hose that goes from the aux. water pump on the passenger side fender into the heater core. Using my garden hose, I sprayed some water in the hose and it came back out of the aux. water pump. (The nipple that the hose I am spraying in came off of.) So that tells me that coolant is flowing through the heater core, through the heater control valve and back out the aux. water pump. So could my heat problem be the aux. water pump not functioning? I just replaced it when I found the old one leaking. Is there a way to test it?

If the aux. water pump (For the heater not the one on the radiator) wasnt pumping, what would my symptoms be?

for the whole story: http://www.cadillacforums.com/forums/cadillac-catera-cimarron-forum/120506-very-little-heat-dealer-results.html
and
http://www.cadillacforums.com/forums/cadillac-catera-cimarron-forum/115155-how-warm-should-heater-get.html

frank moran
11-10-07, 05:08 PM
I am trying to flush my heater core due to a no heat problem. THe dealer checked it out and said there isnt any coolant going through the heater core and recomended a flush for $250. I figured I could do it myself. I disconnected the hose that goes from the aux. water pump on the passenger side fender into the heater core. Using my garden hose, I sprayed some water in the hose and it came back out of the aux. water pump. (The nipple that the hose I am spraying in came off of.) So that tells me that coolant is flowing through the heater core, through the heater control valve and back out the aux. water pump. So could my heat problem be the aux. water pump not functioning? I just replaced it when I found the old one leaking. Is there a way to test it?

If the aux. water pump (For the heater not the one on the radiator) wasnt pumping, what would my symptoms be?

for the whole story: http://www.cadillacforums.com/forums/cadillac-catera-cimarron-forum/120506-very-little-heat-dealer-results.html
and
http://www.cadillacforums.com/forums/cadillac-catera-cimarron-forum/115155-how-warm-should-heater-get.html

you should be able to hear the pump run, if not use a screw driver or other rod as a stethoscope, you should feel and hear it buzz...

catera00
11-10-07, 07:28 PM
you should be able to hear the pump run, if not use a screw driver or other rod as a stethoscope, you should feel and hear it buzz...

When does it run? Is it supposed to be running whenever the heater is at 90 degrees? (after the car reaches operating temp of course) Cause I was holding on to it and felt nothing. Both hoses get hot but I assume the coolant would still flow through it even if it wasnt pumping. Could I maybe use a multi meter on the connector to tell if voltage is getting to it? Just wondering if the problem is with the pump or the connector.

Also, there arent any fuses for that pump right? I looked in the manual and diddnt find a fuse, only a relay labeled "auxilary water pump". I assume its for both pumps.
Thanks alot for the help. Trying to get this heat workin for the family this winter.

frank moran
11-10-07, 09:44 PM
When does it run? Is it supposed to be running whenever the heater is at 90 degrees? (after the car reaches operating temp of course) Cause I was holding on to it and felt nothing. Both hoses get hot but I assume the coolant would still flow through it even if it wasnt pumping. Could I maybe use a multi meter on the connector to tell if voltage is getting to it? Just wondering if the problem is with the pump or the connector.

Also, there arent any fuses for that pump right? I looked in the manual and diddnt find a fuse, only a relay labeled "auxilary water pump". I assume its for both pumps.
Thanks alot for the help. Trying to get this heat workin for the family this winter.

the pump runs all the time, check to see if you have power to it. The fuse is #10 but it controls other items (bcm, coolant pump) so I doubt it's the fuse. You should be able to feel the pump run, After reading your other psot you said you replaced both pumps, so possible you have a fuse/power problem??. Check to see if you have power to the heater booster pump on the right strut tower. Its a 2 lead connection, ground and 12 volts. You have all the symptoms of this pump not working....

catera00
11-10-07, 11:03 PM
the pump runs all the time, check to see if you have power to it. The fuse is #10 but it controls other items (bcm, coolant pump) so I doubt it's the fuse. You should be able to feel the pump run, After reading your other psot you said you replaced both pumps, so possible you have a fuse/power problem??. Check to see if you have power to the heater booster pump on the right strut tower. Its a 2 lead connection, ground and 12 volts. You have all the symptoms of this pump not working....

ok, I checked the pump with the key on and the engine not running. This time I heard and felt it running. I started the car and let it heat up to operating temp. The heater blew at 80 degrees. I unpluged the aux. Heat pump and it went down to 70 degrees after about 2 minutes. I plugged the pump in again and it went up to 80 in under a minute. I will run out to the garage and check the heater booster pump right now. I havent heard of this part yet. What is its function? By right do you mean passenger? What does it look like? And thanks so much for the help.

I took some pics. Is it this wire here on the drivers side?
37416

Otherwise heres a pic of the passenger side. Can it be seen here?
37415

frank moran
11-11-07, 09:14 AM
ok, I checked the pump with the key on and the engine not running. This time I heard and felt it running. I started the car and let it heat up to operating temp. The heater blew at 80 degrees. I unpluged the aux. Heat pump and it went down to 70 degrees after about 2 minutes. I plugged the pump in again and it went up to 80 in under a minute. I will run out to the garage and check the heater booster pump right now. I havent heard of this part yet. What is its function? By right do you mean passenger? What does it look like? And thanks so much for the help.

I took some pics. Is it this wire here on the drivers side?
37416

Otherwise heres a pic of the passenger side. Can it be seen here?
37415

the pump is on the pass side, it has a pair of 1 in. hoses running in and out of it. It has a two wire connection on it, its near the coolent tank, lower, problably just opposite the middle spark plug on that bank. mounted to the strut housing.

catera00
11-11-07, 12:15 PM
the pump is on the pass side, it has a pair of 1 in. hoses running in and out of it. It has a two wire connection on it, its near the coolent tank, lower, problably just opposite the middle spark plug on that bank. mounted to the strut housing.

Oh yeah. Thats the part I have been calling the Auxilary water pump. I guess its the auxilary heater pump. I should have been more acurate. Thats pumping. I can hear and feel it. I also changed the aux. water pump on the radiator recently.
http://img.photobucket.com/albums/v106/neo95hl/catera/DSC04463.gif

I am stuck at this point. I think I have addressed every part related to the heater.


The facts:

-Replaced the aux. water pump
-Replaced Aux. Heater pump. It is pumping and hoses are on correctly.
-Ran water through the top hose that goes to heater core and it flowed back
out of the bottom hose of the heater core (So it isnt plugged)
-I did not change the thermostat but the car reaches operating temp quickly (Just under half way on the gauge)
-I can see both actuator arms moving up and down when I change the temp from 60 degrees to 90 degrees etc. So I assume they are working.

-Eventually the heater will blow at around 100 degrees after about 20 miles of driving. (It takes longer if its 30 degrees or lower outside)

frank moran
11-11-07, 02:12 PM
a couple of thoughts, are you getting a good flow through the heater core, are the actuator motors actually moving...are they connected to the heater doors. ?? ( if available A tech 2 will show the range of motion for the door motors). As a back up If you can get to the actuators move them by hand, in other words you want to make sure they are moving to the full range position for heat. Is the pump actually moving coolent, eg is it pumping (possibly the impeller is broken) just confirm that....I had a corvette that the actuator motor worked but did not go to the full heat range....poor heat...
If you have hot coolent moving through the core and the doors are properly positioned you should have cabin heat.

catera00
11-11-07, 09:21 PM
a couple of thoughts, are you getting a good flow through the heater core, are the actuator motors actually moving...are they connected to the heater doors. ?? ( if available A tech 2 will show the range of motion for the door motors). As a back up If you can get to the actuators move them by hand, in other words you want to make sure they are moving to the full range position for heat. Is the pump actually moving coolent, eg is it pumping (possibly the impeller is broken) just confirm that....I had a corvette that the actuator motor worked but did not go to the full heat range....poor heat...
If you have hot coolent moving through the core and the doors are properly positioned you should have cabin heat.

Well I watch the actuators move from hot to cold and I can see that the arm and the piece that its attached to (I presume its the door it self) move as far as they can go because there is a point that it cant move past. I will have to pull a pump hose off and stick the pump in a bucket and turn the key. Then see if its spitting out coolant. I know people have said they moved the actuator door manually but mine seems so firm that it might break something if I force it. I'll let ya know about the pump. Thanks again

catera00
11-13-07, 03:42 PM
Okay, I tested the auxilary heater pump and it looks like its pumping fine. I took a video of it so you can check it out. I can only assume this is strong enough: http://blankenshipsrv.com/catera/heater-pump.MPG (21MB)

I also tried to film the actuator arm moving incase you can see anything wrong with it. (driver side) http://blankenshipsrv.com/catera/drivers-actuator.MPG (31MB)

Heres what the water pump looks like inside:
http://blankenshipsrv.com/catera/water-pump.gif
http://blankenshipsrv.com/catera/water-pump-fins.gif
http://blankenshipsrv.com/catera/water-pump-internals.gif

The water pump doesnt really seem to have suction to it. I dont feel suction when I put my palm on the intake tube. It seems to really just move the coolant as its being fed to it. I wonder if coolant isnt being "fed" to it properly. I am probably over-thinking this but its a thought anyway. Any thoughts on the pumps functionality or the actuators? Or anything? Thanks again

catera00
11-13-07, 04:28 PM
Now, heres something I discovered, I hooked the garden hose up to the hose that goes from the aux. heat pump to the heater core. I noticed that the hose swells from the pressure. Coolant does come out through the tube coming out of the heater core but very slowly. Like a steady 1 inch wide stream but not nearly as freely as I expected. Maybe thats because the heater core is a tight place resembling the radiator with its small tubes and such. Does any one know if it should be flowing free-er? Maybe the pump isnt strong enough to push water through due to a blockage? Thanks again

frank moran
11-13-07, 10:28 PM
Now, heres something I discovered, I hooked the garden hose up to the hose that goes from the aux. heat pump to the heater core. I noticed that the hose swells from the pressure. Coolant does come out through the tube coming out of the heater core but very slowly. Like a steady 1 inch wide stream but not nearly as freely as I expected. Maybe thats because the heater core is a tight place resembling the radiator with its small tubes and such. Does any one know if it should be flowing free-er? Maybe the pump isnt strong enough to push water through due to a blockage? Thanks again

I could not view the film...from your description it sounds like you have some blockage. The hose swelling is indication of restriction, keep in mind your home water pressure is about 30-40 lbs, your coolent system is designed to operate at around 15lbs. sounds like you had a tight fit on your connections and gave it a good push of water. The core would have some restriction due to it's small size and core passages but I dont know how much. Did this problem occur after the head gasket/head replacement??? how many miles on the car? can you get access to a flush machine, $250 is silly. Talk to a radiator shop about flushing the core, you get an A+ for effort. Another thought...are you positive the thermostat is getting the engine up to temp? do the fans ever have to kick on at idle???

catera00
11-14-07, 12:42 AM
I could not view the film...from your description it sounds like you have some blockage. The hose swelling is indication of restriction, keep in mind your home water pressure is about 30-40 lbs, your coolent system is designed to operate at around 15lbs. sounds like you had a tight fit on your connections and gave it a good push of water. The core would have some restriction due to it's small size and core passages but I dont know how much. Did this problem occur after the head gasket/head replacement??? how many miles on the car? can you get access to a flush machine, $250 is silly. Talk to a radiator shop about flushing the core, you get an A+ for effort. Another thought...are you positive the thermostat is getting the engine up to temp? do the fans ever have to kick on at idle???

Well thanks again for replying. I had a very tight fit on the garden hose. The spray nozel is bullet shaped and fits perfect inside the end of the heater hose. The head gasket and head were replaced in the summer so I didnt test the heat until about 4 months later. So I dont know exactly when the heat became an issue. The head and head gasket was changed and both auxiliary water pumps were changed before I noticed the prob. I do not have access to a flushing machine nor do I have the special tools to remove the hoses from the heater core spouts. But maybe I can get a better deal on a flush from a radiator shop like you suggested. The car has 75k miles on it and the engine reaches operating temp within 1 mile of driving or in about 5 minutes at idle on a 45 degree day. And I have heard the fans kick on after I have pulled into the garage after a long drive. I havent waited for them to kick on at idle. My thermostat would be covered by my warranty but the dealer says it isnt bad so I dont think I can make them change it and have it covered if they say its fine to begin with. But seeing as how it gets to operating temp so quick, I really dont think its the thermostat. I could be wrong though. I will upload those vids to youtube tonight and post new links so you can see em. Thanks once again for the help

catera00
11-14-07, 04:02 AM
Here are the vids on youtube for those who couldnt see the others- Water pump: http://www.youtube.com/watch?v=8dt542vT-34

actuator: http://www.youtube.com/watch?v=23TguiO-Qi0

frank moran
11-14-07, 09:39 AM
Here are the vids on youtube for those who couldnt see the others- Water pump: http://www.youtube.com/watch?v=8dt542vT-34

actuator: http://www.youtube.com/watch?v=23TguiO-Qi0

The heater doors and the pump are working properly, I think at this point you have it boiled down to the core being blocked up...and restricting a flow of hot coolant for heat. You could try a retail type radiator flush, though inmo this may be a waste of time. You can remove the hoses from the core, they have a locking sleeve that you can pull back and release the lock tabs...though removing the hoses serves no purpose at this point, talk to a radiator shop, they have commercial cleaners that can help. Keep us posted. You'll be a beating GM flat rate before your done with this....

catera00
11-14-07, 12:30 PM
The heater doors and the pump are working properly, I think at this point you have it boiled down to the core being blocked up...and restricting a flow of hot coolant for heat. You could try a retail type radiator flush, though inmo this may be a waste of time. You can remove the hoses from the core, they have a locking sleeve that you can pull back and release the lock tabs...though removing the hoses serves no purpose at this point, talk to a radiator shop, they have commercial cleaners that can help. Keep us posted. You'll be a beating GM flat rate before your done with this....

Scheduled for Friday at 9am. I'll keep my fingers crossed. I'll check back with results. Thanks for all the help!

catera00
11-14-07, 04:34 PM
Is there any way my thermostat could be faulty? I know the usual signs are either it being stuck closed causing overheating or it being stuck open causing the car to take a long time to reach operating temp. Mine reaches operating temp within 1 mile of driving or about 5 min. idling and never dips back below that point and never goes higher than that point.

At operating temp. the heater blows at 80 degrees. After about 10 miles driving it will usually go up to 90 or 100. Is there any way my thermostat could be half open or something? What signs would there be if it was? Just a thought

frank moran
11-14-07, 07:19 PM
Is there any way my thermostat could be faulty? I know the usual signs are either it being stuck closed causing overheating or it being stuck open causing the car to take a long time to reach operating temp. Mine reaches operating temp within 1 mile of driving or about 5 min. idling and never dips back below that point and never goes higher than that point.

At operating temp. the heater blows at 80 degrees. After about 10 miles driving it will usually go up to 90 or 100. Is there any way my thermostat could be half open or something? What signs would there be if it was? Just a thought

you have what looks like a stat that is working, though the fact that the gauge never goes higher than mid range makes me wonder. If you can get someone to put a scan tool on it that will give you accurate info and you can correlate it to what the guage shows.... other then that its a guess. The alternative is to put a new stat in, unfortuantley it's a pain to put a stat on this engine. Do yau have a local guy with a scan tool, a couple of bucks spent there may be helpful. I have a Snap-on but your a 1000 miles away.

catera00
11-15-07, 03:15 AM
you have what looks like a stat that is working, though the fact that the gauge never goes higher than mid range makes me wonder. If you can get someone to put a scan tool on it that will give you accurate info and you can correlate it to what the guage shows.... other then that its a guess. The alternative is to put a new stat in, unfortuantley it's a pain to put a stat on this engine. Do yau have a local guy with a scan tool, a couple of bucks spent there may be helpful. I have a Snap-on but your a 1000 miles away.

Well sometimes it will go above the half point when I park but the fan kicks in and it goes right back down. I dont know anyone with a scan tool but if my flush doesnt do the trick I'm gonna haul it in to the dealer and talk them into changing the T-stat as a favor. They can write it off to the warranty since its covered. I have been in and out of there so much that they always feel bad when I have to drag the thing in there. In the first month I had it, I had it in there about 6 times for a check engine light & disapearing coolant. After a new MAF, Plugs, coil pack, and a couple other parts they got it right. Ended up being a head gasket and a severely warped head. All was covered by warranty thank goodness. But if the flush and god forbid, a new Tstat doesnt fix it, I seriously will have no clue. Unless the damn actuator door fell off inside or something =P I'll keep you updated. Thanks a lot

catera00
11-21-07, 03:11 PM
Okay, I didnt have the flush done. I took the car in to the dealer who I have my warranty through and the went through and tested the cooling system and everything is working properly. The thermostat is functioning properly as well. They determined that coolant is not flowing through the heater core. They said its pluged. They dont know what is causing the blockage but it needs to be replaced. ($1200) yipe. So I know coolant does flow through it from my garden hose test, but just barely. Is there anything that can be run through there to un plug it or is it just toast? I dont know how it worked last winter and got blocked over summer. Also, I suppose I can be looking forward to the heater core springing a leak at some point due to the blockage? Good times.

frank moran
11-21-07, 08:13 PM
Okay, I didnt have the flush done. I took the car in to the dealer who I have my warranty through and the went through and tested the cooling system and everything is working properly. The thermostat is functioning properly as well. They determined that coolant is not flowing through the heater core. They said its pluged. They dont know what is causing the blockage but it needs to be replaced. ($1200) yipe. So I know coolant does flow through it from my garden hose test, but just barely. Is there anything that can be run through there to un plug it or is it just toast? I dont know how it worked last winter and got blocked over summer. Also, I suppose I can be looking forward to the heater core springing a leak at some point due to the blockage? Good times.

You could talk to the rad shop and see if they have any thing that will clean up the core (w/o eating the metal away). Possibly at one time a sealer was used to address the head gasket problem??? personally, items in a can other then oil just dont always produce the best results. You can get a core for around $200...it requires a bit of work, r&r the steering column, the entire instrument panel etc. A lot of screws but the job is not heavy. The core will not leak from the situation you described...

catera00
11-22-07, 12:45 AM
You could talk to the rad shop and see if they have any thing that will clean up the core (w/o eating the metal away). Possibly at one time a sealer was used to address the head gasket problem??? personally, items in a can other then oil just dont always produce the best results. You can get a core for around $200...it requires a bit of work, r&r the steering column, the entire instrument panel etc. A lot of screws but the job is not heavy. The core will not leak from the situation you described...

Someone may have used some stop leak or something before I owned it. Who knows. I will call a radiator joint friday and see what they recommend. So the steering column comes out, inst. panel. I heard the whole dash had to be removed. What else comes out? (In general I mean. I would buy a manual if I decided to do it so I'm not asking for granular details. ) I was trying to find a thread about heater core replacement on here.

frank moran
11-22-07, 01:29 PM
Someone may have used some stop leak or something before I owned it. Who knows. I will call a radiator joint friday and see what they recommend. So the steering column comes out, inst. panel. I heard the whole dash had to be removed. What else comes out? (In general I mean. I would buy a manual if I decided to do it so I'm not asking for granular details. ) I was trying to find a thread about heater core replacement on here.

Why not ask the dealer for a look at his service manuals for your model, copy the respective pages. The column removal is in the Steeing Susp book and the IP removal is in the HVAC book, 2 separate books. I have them but have no way of scanning them.
Possibly you could remove the hoses from the heater booster pump and do a direct flush of the heater core from that location, this would be a more concentrated effort.??...The calcium deposits can be almost impossible to remove, as an example radiators used to be rodded out by remvoing the the side tanks and pushing rods through the tubes, point is the stuff can be quite hard to remove...
If you dont want to take the job on yourself , possibly an AC heater shop would give a better price, they are used to removing dash panels as most modern cars today require this to repalce the ac evap...

catera00
11-23-07, 10:45 PM
You could talk to the rad shop and see if they have any thing that will clean up the core (w/o eating the metal away). Possibly at one time a sealer was used to address the head gasket problem??? personally, items in a can other then oil just dont always produce the best results. You can get a core for around $200...it requires a bit of work, r&r the steering column, the entire instrument panel etc. A lot of screws but the job is not heavy. The core will not leak from the situation you described...

I called them today and they say what is commonly used in the industry is Drano. That they put Drano in using a funnel and flush it out after a while. And dont leave it in too long. I dont know how long their talkin. Maybe 10 minutes or so I assume. I guess it couldnt hurt at this point as long as I flushed it all out very well so as not to get any drano in the cooling system.

catera00
02-20-08, 11:37 PM
Well, just a little update on this. I took it to the dealer to have ther heater core replaced and they flushed it first and guess what? It works now. It was just plugged up. Too bad I canceled that $30 flush job appointment cause I paid $250 for it at the dealer. But its ok because I was expecting $1200 for the core. So thats pretty awesome. Now to get the EBTCM rebuilt. Sheesh, does it ever end???

catera56
02-21-08, 05:58 PM
aux. pump is designed to help coolant flow through the heater core at idle only-electric coolant pump mounted on radiator is designed to run under certain conditions with the key off to help cool down engine since coolant temp. raises after the engine is shut down.with the engine hot,hand fill the heater hoses.they should be nearly the same temperture,HOT.if water valve has been replaced {which is almost a given} make sure the coolant hoses are installed correctly.it is poss for core to be partially stopped up and still show coolant flow.you said actuators are working ok.if all above is good,put your hand on the face of the heater core with engine hot.the complete face of the core should be hot.however,due to location of core and access to it,this would be last step.