cleaning heater core

[Jakegday]

hello all. ive come to realize the heater core on my ford fairmont is clogged. i replaced the coolant this summer and the old coolant was literally brown.
my heater never gets hot. so i let the engine get all the up to temp, then i feel the 2 hoses under the hood that go to and from the heater core. one is clearly warmer then the other. the blend door is working and i dont believe my car has a valve that shuts water to the core on and off.

so my question is, can i, and if so how, would i go about unclogging my heater core?

 

[JHZR2]

Wow, you still have a fairmont? My parents had a 1979 or 1980. 4 cyl and MT, no AC. Post a few pictures of the car if you have some.

There are various ways. The first attempt would be to follow the instructions for a safe product like RMI 25 or Schaeffer's Clean and Cool. Let the gentle chemical action do its thing.

if it is truly clogged, this may be a good first start, but not do everything. Then, Id pull the hoses that go to/from the heater core, and rig the outlet so that you can attach a hose. I'd then backflush the system.

Once you get it marginally working, Id look at the instructions for how to do citric acid flushes (common on MB cars). this is a good technique.

I would recommend changing multiple times even after getting the core working, to help really clean out the system.

Good luck!

 

[Jakegday]

lol, i dont STILL have one. i just bought it this May as a toy

edit: yeah ill try to get some pics up here soon for ya

 

[demarpaint]

I posted this in another thread, it could possibly help you.

I had a problem with the heat in a 95 Caprice and a 96 Blazer my son had. Both times I disconnected both heater hoses and set up the garden hose to the heater hose. With low pressure from the hose I flushed out the heater core. In both instances heat was restored and no problems arose while we owned the vehicles.

I'd flush the cooling system first, then do the heater core as I mentioned. Refill with the proper mix and bleed the system. HTH

 

[lipadj46]

Originally Posted By: demarpaint
Both times I disconnected both heater hoses and set up the garden hose to the heater hose. With low pressure from the hose I flushed out the heater core. In both instances heat was restored and no problems arose while we owned the vehicles.


+1 this has worked for me too.

 

[roadrunner1]

once i set up a sump pump in a bucket and circulated a citrus cleaner through the heater core seperately after i flushed the engine. heater works very good after 2 or 3 years

 

[Shaman]

flush the heater core, then use the aforementioned slow cleaners. Less [censored] to clean in the heater core equals better ability to clean other stuff.

 

[wander2039]

Eh live on the wild side dump a capful of mmo in there.. see what happens. You might look where the lines for the heater is connected. I know on my dad's 86 F150 majority of those fittings was clogged solid.

 

[demarpaint]

Originally Posted By: Eric Smith
Eh live on the wild side dump a capful of mmo in there.. see what happens. You might look where the lines for the heater is connected. I know on my dad's 86 F150 majority of those fittings was clogged solid.


I've read a few stories people about adding MMO to the cooling system, something I've never done but am curious about. since MMO is a thin oil along with some other goodies how does it mix with coolant and water?

 

[wander2039]

This is just what I noticed: It did tint the coolant a tad bit red.. you can see some oil floating on top. I didn't run it very long nor did I use very much since I would consider it a "hard" cleaner versus the citric acid versions. Not sure how it would work long term although I didn't do a "complete" flush or clean-out when I changed the thermostat. Although everything the cooling system is made of isn't any different than the fuel and oil and MMO isn't known to cause any problems in either of those. Like I said in my other thread it was the cleanest Festiva out of 5 or so I've seen internally but that could be from alot of things. Seeing what MMO did to the battery acid didn't suprise me.

 

[demarpaint]

Like I said I read about it, saw someone on the MMO forum ask about doing it and no one really answered the question IIRC. Something worth looking into I guess.

 

[lipadj46]

Why dump MMO (nonpolar) in coolant (polar) when they have many different flushes along with the grocery store stuff like CLR, Simple Green etc? Flush it and be done with it before winter really kicks in.

 

[PW01]

What about using an air compressor to blow out the core?

 

[demarpaint]

Originally Posted By: lipadj46
Why dump MMO (nonpolar) in coolant (polar) when they have many different flushes along with the grocery store stuff like CLR, Simple Green etc? Flush it and be done with it before winter really kicks in.


That's why I never dumped it in. I read about it and thought I'd ask since it was mentioned here. I always went by the oil and water don't mix rule and stuck with it. But I'm here to learn too.

 

[mechtech2]

The quick way is to simply run water from a hose BACKWARDS through the heater core.
This would be from the side that is cold now, and coming out the hot side.
Hopefully, this will be enough.
You may need to go further and use chemicals or get another core, but try this first.

 

[dwendt44]

I've done that. Reversing the flow back and forth until water runs clear.
That will help some.
IF at highway speeds you still get no heat, it's time to replace or repair(radiator shop).

 

[Kestas]

Is there any chance that somebody put a 'stop leak' product in there at any time?

 

[mechtech2]

Kestas - It's not polite to talk like that about the dead! UGHH!

 

[lipadj46]

Originally Posted By: Kestas
Is there any chance that somebody put a 'stop leak' product in there at any time?


Yes a stop leak product will do it too, especially if you have to dump it in the expansion tank.

 

[severach]

The colorant may come out of the MMO but as oil it will move to and float at the highest point, usually at the radiator cap where it will get pushed into the overflow tank and never get drawn back. Just say no to oil in the cooling system.

The heater core on some Ford models are super easy to replace. Glove compartment, 9 bolts off a cover, pull core out. If it's that easy then replace it.

For those like my 1999 Dodge Dakota that is 5 hours out including the entire dashboard, and more back in, I flush with air and water. Siphon some coolant into a clean container to lower the system level. Pull one heater hose and slowly blow the coolant into the engine to avoid wasting it. Pull the remaining heater hose. Alternately fill with water then blow with air reverse of normal flow. Once the initial color is gone then every flash of color you see is another runner opening up. You're going to get wet.

A new core is best but this can get you heat for a few more winters.