Jump to content
Ultimate Subaru Message Board
Deener

Is there any other way? - Heater Core clogged

Recommended Posts

Hi all,

 

EA 82 - 88 GL Wagon (no ac, 3at tranny, on demand

 

I flushed my heater core last night and I found that she's really clogged. I ran the hose through it both ways for about 45 minutes and I was able to get about twice the flow out of by the end but it's still not 100% unclogged. The water runs clear through it now but I it's not enough to produce tons of heat in the cab. I have increased the amount of heat so I do get heat but I know it can be better. That brings me to ask if there is any sort of addative that I could use to clean that core out? I have heard of using vinegar for a couple days and then doing a full flush but I thought I'd ask you folks first in case there's something that truly works or at least has worked for someone. I really don't want to pull the dash off and replace the core.

 

Dean

Share this post


Link to post
Share on other sites

Drano!

make sure you disconnect both heater hoses from the engine. Use a small funnel, once water starts flowing freely, flush with lots of water with baking soda in it to nutralize the acid. Have done this many a times with older cars.....

Share this post


Link to post
Share on other sites

+ 1 on draino, you can have some sort of mineral scale buildup, muriatic acid works good too, just be careful of splashing it in your face, sounds like you have it isolated from your engine already, good luck

Share this post


Link to post
Share on other sites
Drano!

make sure you disconnect both heater hoses from the engine. Use a small funnel, once water starts flowing freely, flush with lots of water with baking soda in it to nutralize the acid. Have done this many a times with older cars.....

..is there a "time" that you let the "drano" sit before flushing with water

Share this post


Link to post
Share on other sites
..is there a "time" that you let the "drano" sit before flushing with water

 

I add a little water to help it flow when I add the drano, I would only allow it to work for a minute or two and then start flushing, might have to do it twice if its not flowing much from the other end from the frist treatment.

Share this post


Link to post
Share on other sites

DRANO! Of course...thanks guys. I will definitely 'giver' a shot. Obviously not too much otherwise I'll gut the thing but a little bit with couldn't hurt.

Share this post


Link to post
Share on other sites

yes the "other way". is to use a dremmal tool and open up the plastic caseing on the drivers side of the heater core area. hunker down and look in from the drivers side at the area where the heater hoses go into the heater core. i just cut away enough plastic so as to pull the old heater core out,kinda like pulling out a tape deck or radio(hope this is all making sence) once you have the old core out make sure there is no sharp edges ect that could put a hole in your new core(the last time i got one from napa it was around $80 bucks i think).once you have the new one in place some zip tyes and some calking will hold it in place.i have replaced 3 or 4 heater cores this way.like you said who wants to pull or split the dash(those enginerers!!!) so again i hope this makes sence and works well for you.happy trails,todd:banana:

Share this post


Link to post
Share on other sites

What I've done on many others is after flushing with water is just hook the hoses up backwards of the way they were and just drive it. It will be back flushing while you drive. It may take a week but will most always fix them. That way you don't need to worry about having any lingering acid in your system. After it cleans itself just drain and refill the cooling system.

Share this post


Link to post
Share on other sites
What I've done on many others is after flushing with water is just hook the hoses up backwards of the way they were and just drive it. It will be back flushing while you drive. It may take a week but will most always fix them. That way you don't need to worry about having any lingering acid in your system. After it cleans itself just drain and refill the cooling system.

 

 

That ^ sounds like a neat idea. Only concern (or question) I have is: wouldn't the gunk that's flushed from the heater core then get caught up in the main radiator, causing a bigger problem?

 

I like the simplicity of JWS' method.. I'm just throwing my question out there for more comments/opinions :)

Edited by NV Zeno
rephrase for clarity

Share this post


Link to post
Share on other sites

Yes there is a very slight chance that it could cause issue with the rad. But one thing to remember, the heater core passages are much smaller than the radiators. I still recomend doing a drain and fill after the heater starts clearing up. I had to do this to my '88 dl and a buddies '88 gl.

Share this post


Link to post
Share on other sites

The heater core passages are basically the same size as the radiator. The tubes are small - about 1/8" to 3/16" ID.

 

Just pull the dash out. It's not that hard and it's worth it to replace bad foam, remove dust and dirt, and sanitize.

 

GD

  • Like 1

Share this post


Link to post
Share on other sites

I've done several by dissolving automatic dishwasher detergent in hot water and then putting that in the core overnight. Flush in both dorections the next day and watch al the crap come out. After that, I had the best heat ever. I've done an ea82 radiator that way too.

Share this post


Link to post
Share on other sites

AS107.jpg

 

must drain antifreeze first, put this in, fill remaining with plain water, drive around a few days always with heat set to hottest to cuirculate it max. with this in there, reverse hoses to core at some point. the reverse again. FOLLOW ALL instructions. Since its water with this, make sure the car is not in below freezing temps ever.. with this in there.

Drain radiator of the flush.

Refill with proper coolant.

Share this post


Link to post
Share on other sites

yes the "other way". is to use a dremmal tool and open up the plastic caseing on the drivers side of the heater core area. hunker down and look in from the drivers side at the area where the heater hoses go into the heater core. i just cut away enough plastic so as to pull the old heater core out,kinda like pulling out a tape deck or radio(hope this is all making sence) once you have the old core out make sure there is no sharp edges ect that could put a hole in your new core(the last time i got one from napa it was around $80 bucks i think).once you have the new one in place some zip tyes and some calking will hold it in place.i have replaced 3 or 4 heater cores this way.like you said who wants to pull or split the dash(those enginerers!!!) so again i hope this makes sence and works well for you.happy trails,todd:banana:

can this be done on a 1988 subaru GL? I've seen some pictures where you see the heater lines under the dash but when i look under my dash i can't find them and it looks a little bit different. Perhaps it is only possible on an ea81? I've flushed my heater core a few times and i've used drano twice but it still isn't as hot as i need it to be. I'd love to put a new core in there but i dont want to remove the dash. I'm hoping i can cut my old one out. Thanks 

Share this post


Link to post
Share on other sites

After I flushed my heater core through it leaked like a sieve and I couldn't find another... so.. http://www.nagara.co.uk/core.htm it didn't work completely as planned so when time allows I'll make a better one.

 

d3bab7c5.jpg

 

Works enough to keep the screen clear in minus10 degrees C but not enough to keep me warm sans coat..!

Share this post


Link to post
Share on other sites

to remove the heater core is impossible to do it without removing the enterily dash?

 

i was hoping to be able to cut it out with a dremel but looking at my 1988 GL that looks impossible. 

Share this post


Link to post
Share on other sites

If you're methodical and take is easy, removing the dash is not so much difficult as time consuming and bad for your back (us oldies don't like being upside down!). Once my dash was loose I tied it up with sash cord and then had a friend help me carefully lift it out. When putting it back, I did the same: suspended it on cords while I reconnected everything before finally lowering it to its position. Not all can be connected with it hanging but most can and, because one can lower it gradually (cords through window and over roof), it's easy enough to raise it if a wire gets trapped in the wrong place. Don't be scared of doing it, just take your time and follow the instructuions in the Haynes.

  • Like 1

Share this post


Link to post
Share on other sites

Also, for cleaning, I would advise against using Drano or any other metal-hydoxide based material.  These work on organic blockages but not on most inorganic/mineral blockages (such as you would find in cooling systems).  Cooling systems need an acid to dissolve deposits... but the acid is also likely to attack the metals in the cooling system, especially the aluminum.  That is probably why most commercial flush/cleaners have gotten away from using oxalic acid and gone to just using detergent.  (Plus the environmental harm from using oxalic acid.)

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×