Clogged Heater Core

[Steve@Advance]

Tomorrow I'm supposed to look at a clogged heater core on a 2010 Impala.

This has been an ongoing problem, the owners late husband had back flushed it a couple times, only lasts a year or so, then clogs again. To my knowledge the cooling system has always had good antifreeze, no other issues with overheating. She asked me to take a look at it.

I don't know how he flushed it, probably with the garden hose. I'm thinking blow it back with compressed air, but don't want to start it leaking.

Any ideas? Chemicals? Just water? Or go ahead and replace it?

Thanks!

 

[Super H Mike]

I use water and compressed air. I disconnect the hoses at the engine, not the heater core ( too easy to damage the core ) and fill the hose with water, then blast it with air. Work it both ways a few times each. I put the outlet hose into a 5 gallon bucket so I can see what comes out. It is always crusty looking small pieces of scale and rust. I use extension hoses on some cars. Certain models are more prone to the clogging, such as early 2000's Taurus cars. I have some cars I do every year for people. I have never damaged a core or failed to get it cleaned out using this method.

 

[Liquid_wrench]

Maybe thermostat? or low coolant...just enough to not blow hot air...might just be air in system...my 06 impala was low,after I flushed the system and didn't get enough dexcool back in.

Keith

 

[Fred Werring]

Daughter had an 03 LeSabre, was constantly plugging up.

Put one of those garden hose taps in both heater hoses so I could flush both ways, took radiator hoses to flush the engine, used radiator flush chemicals, never could seem to get all the gummy dexcool out. I could get it to last a few months...glad when she got rid of the car.

Probably a previous owner used a non compatible antifreeze in with the dexcool, I read somewhere that's what turns it to gunk.

I did learn the hard way about burping the thermostat on that V6...wound up drilling a small hole in the thermostat so it would self burp.

FWIW

Fred

 

[Bob in SD]

I flushed my sons Buick and then filled the heater core with a bottle of CLR and hot water. Let it sit for half an hour and flushed with water. It did get some more brown goo out (flushed till it ran clear with water, then did the soak, bot more dirt out). Not sure how it would compare to the specialized chemicals.

 

[robgIN]

If at all possible, reverse the hoses and you will be good to go, an old trick that really works. Some have different size nipples and makes this less practical but if they are the same size just reverse the flow , I have done it many times and it hasn't failed yet.

 

[David G]

I think there were issues with different types of anti freeze on the GM's.

 

[onefarmer]

I've flushed many cores like Mike. Air blowing water thru the core to flush. I find it takes more pressure then just a garden hose can provide. And just air does nothing. After more than a dozen cores I've flushed I haven't blown one yet.

 

[Bob Harvey]

You got forever to fix it ? Replace is my first choice - et voila !

 

[Hoenes]

Garden hose is ok reversing direction of flow. Turn the pressure down though, as about 10 psi is all it will accept without damage. (recommended system pressure)Most houses have close to 60 psi. Of course release the out flow to the ground. Did my wifes Impala, and got out a lot of calcium rocks. Heats good now.

 

[4play]

Repeat clogging of a heater core is a symptom not the problem. I would pressure flush, double and triple flush the entire cooling system. I bet at least 1/4 of the radiator is clogged too.

 

[Sprint 6]

Heater core is not likely plugged. It likely has a headgasket on the rear bank seeping coolant, running it low, then air locking the heater core. Heater core is in a bad place in the cooling system on an Impala, they air lock very easy.