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Best cleaner to flush a heater core #3176971
11/03/13 10:15 AM
11/03/13 10:15 AM
Joined: Nov 2005
Posts: 394
Ky
nomochevys Offline OP
nomochevys  Offline OP
Joined: Nov 2005
Posts: 394
Ky
Still trying to work out some kinks. I have heat but its nowhere near what it should be. Truck is a 96 GMC Sonoma 4.3. I am pretty much convinced the heater core is plugged up to some degree. What is the best thing I can use to help clean it out with?

Re: Best cleaner to flush a heater core [Re: nomochevys] #3176984
11/03/13 10:29 AM
11/03/13 10:29 AM
Joined: Sep 2005
Posts: 5,758
MIchigan
Warstud Online content
Warstud  Online Content
Joined: Sep 2005
Posts: 5,758
MIchigan
What have you done so far to get more heat?

Re: Best cleaner to flush a heater core [Re: nomochevys] #3176996
11/03/13 10:35 AM
11/03/13 10:35 AM
Joined: May 2010
Posts: 9,182
North Carolina
spasm3 Online content
spasm3  Online Content
Joined: May 2010
Posts: 9,182
North Carolina
I was under the impression that most heater cores today, always have flow. On older cars, the heat control shut off flow to the heater core and this caused gunk and build up. Are you sure the engine is up to temp, that the coolant is not low, and that the air flow blend door is working?


13 elantra 70k 5w30 QSUD
03 chevy avalanche79k synpwr 10w30
01 saturnsc1 185k synpwr rebuilt
17 mazda cx-5 5600 miles m1 0w30
Re: Best cleaner to flush a heater core [Re: nomochevys] #3177005
11/03/13 10:45 AM
11/03/13 10:45 AM
Joined: Dec 2002
Posts: 42,138
New Jersey
JHZR2 Offline
JHZR2  Offline
Joined: Dec 2002
Posts: 42,138
New Jersey
Citric acid flush and degreasing per the MB FSMs.

Re: Best cleaner to flush a heater core [Re: nomochevys] #3177009
11/03/13 10:47 AM
11/03/13 10:47 AM
Joined: Oct 2012
Posts: 2,466
Staten Island, NY
michaelluscher Offline
michaelluscher  Offline
Joined: Oct 2012
Posts: 2,466
Staten Island, NY
If you've fully established that the heater core is plugged.
CLR would be quite good, a couple vinegar rinses after that would be good.


'06 Toyota Camry SE V6 3MZ-FE 100k
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Re: Best cleaner to flush a heater core [Re: nomochevys] #3177016
11/03/13 10:54 AM
11/03/13 10:54 AM
Joined: Dec 2012
Posts: 426
The Tropical Fine City
Sawdusted Offline
Sawdusted  Offline
Joined: Dec 2012
Posts: 426
The Tropical Fine City
Eric the car guy did a youtube video on that some time ago. He used some cleaner plus compressed air to blow out the crud. I think it's a good video. Watch it if you get a chance.


2003 Lexus RX300, 1MZ-FE
2011 Volvo S60, 2.0T, B4024T6
Re: Best cleaner to flush a heater core [Re: nomochevys] #3177021
11/03/13 10:56 AM
11/03/13 10:56 AM
Joined: Apr 2010
Posts: 1,084
Ontario , Canada
nitehawk55 Offline
nitehawk55  Offline
Joined: Apr 2010
Posts: 1,084
Ontario , Canada
Feel the heater hoses . If they are hot it's flowing , cool not .


05 Ford Five Hundred AWD 3.0 DOHC V6 CVT tranny
Re: Best cleaner to flush a heater core [Re: spasm3] #3177032
11/03/13 11:05 AM
11/03/13 11:05 AM
Joined: Mar 2012
Posts: 3,492
NJ, USA
yonyon Offline
yonyon  Offline
Joined: Mar 2012
Posts: 3,492
NJ, USA
Originally Posted By: spasm3
I was under the impression that most heater cores today, always have flow. On older cars, the heat control shut off flow to the heater core and this caused gunk and build up. Are you sure the engine is up to temp, that the coolant is not low, and that the air flow blend door is working?


This is not so much the case. There are plenty of modern cars that use a heater control valve to shut off coolant flow to the heater core and also quite a few that use a heater control valve to negate the need for a hot/cold blend door.

This heater doesn't have that. If it's partially clogged, some sort of weak acid and lots of water should be used. If that doesn't work it's time for a new one.

Re: Best cleaner to flush a heater core [Re: nomochevys] #3177033
11/03/13 11:06 AM
11/03/13 11:06 AM
Joined: Jun 2003
Posts: 17,484
Deplorable in apple valley, ca
Chris142 Offline
Chris142  Offline
Joined: Jun 2003
Posts: 17,484
Deplorable in apple valley, ca
Air and water if its plugged up


02 Wrangler durablend 10w40
87 F250 traveler 15w40
04 Tahoe super-s 10w30
Z400 castrol T 10w40
Can am maveric edge 5w40
57 case tractor 15w40
Re: Best cleaner to flush a heater core [Re: nomochevys] #3177070
11/03/13 11:27 AM
11/03/13 11:27 AM
Joined: Mar 2009
Posts: 657
PA
PhillyJoe Offline
PhillyJoe  Offline
Joined: Mar 2009
Posts: 657
PA
I had little heat in my '07 Grand Prix. I flushed the system of dexcool and changed the thermostat. Heater hoses were hot to the touch. Still had little heat. New coolant was clear of gunk. Starting to think I had a bad core.
Read up on how to replace a heater core and thought, there has to be another answer.
Since one heater hose already has the flush "t", I cut the other and put in another t. I hooked up the garden hose to to one heater hose and squeezed the nozzle - out came rusty colored pudding. It ran clear in a few seconds. Then I hooked up the nozzle to the other hose to back flush. Surprisingly, more gunk came out. Hooked the hoses back to normal, refilled the coolant I lost, bled the system, and you could cook a roast in the car now.

Re: Best cleaner to flush a heater core [Re: PhillyJoe] #3177081
11/03/13 11:38 AM
11/03/13 11:38 AM
Joined: Jul 2008
Posts: 9,808
New Jersey
crazyoildude Offline
crazyoildude  Offline
Joined: Jul 2008
Posts: 9,808
New Jersey
i disconnect both hoses from the heater core and blast through water in one direction then the other a few times that works great


Check To See That The Oil Jugs You Buy Have The Exact Amount Of Oil In Them And Have An Inner Seal Under The Cap. I Use Mobil 1 And Fram Ultra Filters
Re: Best cleaner to flush a heater core [Re: nomochevys] #3177102
11/03/13 12:04 PM
11/03/13 12:04 PM
Joined: Jun 2013
Posts: 1,720
Virginia
mattwithcats Offline
mattwithcats  Offline
Joined: Jun 2013
Posts: 1,720
Virginia
Disconnect the hoses and run some water from a garden hose in.

If this does not work, a teaspoon or two (max 3 teaspoons or a tablespoon) or plain dishwasher detergent.
No lemon scent, not orange scent.
Not CLR or anything acidic, heater core is very thin aluminum.

Rinse out the core, reconnect...

Last edited by mattwithcats; 11/03/13 12:05 PM.

2009 Smart Pure
Pennzoil Platinum Euro 0W-40, Purolator Synthetic PSL 14610, 45 mpg...
185/55R15 General HP tires, "H" speed rated, 44 psi (300 kpa)
Re: Best cleaner to flush a heater core [Re: nomochevys] #3177119
11/03/13 12:22 PM
11/03/13 12:22 PM
Joined: Apr 2010
Posts: 1,084
Ontario , Canada
nitehawk55 Offline
nitehawk55  Offline
Joined: Apr 2010
Posts: 1,084
Ontario , Canada
Important to flush core in both directions .


05 Ford Five Hundred AWD 3.0 DOHC V6 CVT tranny
Re: Best cleaner to flush a heater core [Re: nitehawk55] #3177123
11/03/13 12:27 PM
11/03/13 12:27 PM
Joined: Dec 2009
Posts: 25,600
Regina, Saskatchewan, Canada
Garak Offline
Garak  Offline
Joined: Dec 2009
Posts: 25,600
Regina, Saskatchewan, Canada
Originally Posted By: nitehawk55
Feel the heater hoses . If they are hot it's flowing , cool not .

And if there's a problem, how hard is it to change on this vehicle? If it's a relatively easy change (under 20 minutes on my F-150, hours upon hours on the old LTD), it isn't even worth playing with if it's clogged or weak.


Plain, simple Garak.

2008 Infiniti G37 - Shell ROTELLA T6 Multi-Vehicle 5w-30, NAPA Gold 7356
1984 F-150 4.9L - Quaker State GB 10w-30, Wix 51515
Re: Best cleaner to flush a heater core [Re: Garak] #3177157
11/03/13 01:18 PM
11/03/13 01:18 PM
Joined: Apr 2010
Posts: 1,084
Ontario , Canada
nitehawk55 Offline
nitehawk55  Offline
Joined: Apr 2010
Posts: 1,084
Ontario , Canada
Originally Posted By: Garak
Originally Posted By: nitehawk55
Feel the heater hoses . If they are hot it's flowing , cool not .

And if there's a problem, how hard is it to change on this vehicle? If it's a relatively easy change (under 20 minutes on my F-150, hours upon hours on the old LTD), it isn't even worth playing with if it's clogged or weak.


Feeling the heater hoses is a simple test just to give you an idea if the core is plugged or not . Totally plugged or almost they will be cool to warm compared to the engine hoses . If hot it should be OK but a flush is always the first method to try and clean out and it generally helps unless it's really plugged bad .Even if the hoses are hot it still is good to flush if you feel you are not getting the heat you should . Always the risk of there being a leak afterward though if lots of corrosion going on .
Make sure your engine is coming up to proper op temp or the thermostat is suspect .And of course check the operation of the heater doors or a flow valve if it has one .

How long ? no idea .

Last edited by nitehawk55; 11/03/13 01:21 PM.

05 Ford Five Hundred AWD 3.0 DOHC V6 CVT tranny
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