How do you flush the heater core?

[Trev]

So lately its been dipping below the 0 mark and my heater all the sudden doesn't want to work. It takes for ever to start to blow warm air (20+ min).

So i checked both the coolant lines to the heater, passenger side is warm/hot and the driver side line is cold.

First thing i did was open the bleeder on the hard line. Didn't do anything.

So next step is to back flush the heater core. Can any one elaborate on how exactly to do this? i can get to the driver side easily but the passenger one i can even see where it connects to...

Is all the coolant going to spill out the engine when i start to disconnect the lines to the heater?

How do i back flush it?

TIA

[A4Avant02]

Take a look at this: http://www.audizine.com/forum/showth...t=Heater+Flush

or this: http://www.audizine.com/forum/showth...t=Heater+Flush

The search feature works pretty well too....

[Trev]

First off both the links are the same.

Second it only half answers one of my three Q's.

Thanks for your hard work tho.

[JMRQuattro]

ok....

Step 1: go to home depot and buy a female hose adapter which would normally be used for a hose repair. It look like this:


Step 2: go to an auto parts store and buy some heater core hose, which is also pictured. You're not actually going to replace your existing hose, it'll just be for the flush.

Step 3: Make 2 sections out of the heater core hose, one short and one long. The long peice ideally should be atleast 2 feet long for ease of draining.

Step 4: Hook up the female adapter to the short hose...


Step 5: Screw in your garden hose to the other end

Step 6: Remove both hose clamps and pull off the existing heater core hose where it connects to the firewall. This may be a bitch if you haven't ever removed them just keep working at it though. It might take 2 people.

Step 7: There will be 2 metal pieces sticking out once the hose is removed. The lower one is the in-flow and the top right is the outflow. Attach the short hose and garden hose to the outflow. Attach the long hose to the in and put the other end in a large bucket.

Step 8: turn on the hose, lightly at first, and then slowly build up pressure so you don't make your heater core leak into your car.

Step 9: switch hoses and repeat flush. Repeat until water is clear.



The other alternative is if you have an air compressor, remove the heater core hoses and spray the air compressor into the outflow. You may want to do both. I did both and the air compressor helped remove stuff even after the water flush.

Step 10: After the flush, using either method, i would recommend doing a coolant flush as well and bleeding the air from the system. If air gets into the heater core it will also cause heater issues.

[dirtybrd]

It shouldn't plug up as it's a constant flow system. If it does, you may have other coolant issues.

[JMRQuattro]

^^ yep. My heater worked for a couple days after i did all of that, then due to a coolant leak, air got in the system and what do you know.... heater problems!

I need to find the source of this leak to figure it out. I'm really hoping it's not in one of my cylinders. Just curious dirtybrd, how much of a repair cost would i be looking at if it were?

[dirtybrd]

I have no idea.

[JMRQuattro]

I'm very afraid that i do have a leak in my cylinder because i never see coolant on the ground, but i lose coolant so fast it's retarded. And i'm also very afraid that it's very expensive

[n7plus1]

whats your oil look like?

[JMRQuattro]

^^ i haven't checked actually.

[Trev]

Thanks for the help

When i disconnect the heater lines should i be worried about spilling out all my coolant allover my garage floor?

[JMRQuattro]

^^ maybe... when i disconnected mine i just put a painting tray underneath the car just in case. But it's pretty easy once you disconnect the hoses to just make sure they are pointing upwards and then let them rest against the firewall. If they droop down at all they will start to spill. But there isn't really a hole in that section to drain to the ground so you should be ok. Just be prepared with something under the car just incase of a little spillage.

[dewey527]

finally going to tackle this...and can't seem to get the hoses loose. any suggestions?

[Trev]

channel locks, clamp on to the end (not to tight or you will deform the nipple that the hose is connected to) and give it a twist back and forth. That should loosen her up.

[Trev]

Just to add, this never solved my issues. I still to this day have the same problem.

I'm going to home depot today to make a pressure tester so i can test the coolant system. Ill post back my results.

[boostedAvant]

I'm very afraid that i do have a leak in my cylinder because i never see coolant on the ground, but i lose coolant so fast it's retarded. And i'm also very afraid that it's very expensive

Can't you pull the coils and plugs and shine a light down there and look to see if it's burning in your motor. If the tops of the pistons are clean then your burning coolant.

[dewey527]

just got back from my daughters 3rd b-day party...still can't get the bottom hose off. i know i can not put a lot of pressure due to the inlet so i keep pulling, twisting, grunting and nothing just not a lot of space to work and get a good pull

ps just took out the battery to get more room and still can not budge the hose. i am afraid to put any more pressure on the hose because i don't want to collapse the input feed. i even tried putting an allen wrench between the inlet and hose to loosen things up but nothin'

[dewey527]

bump

[old guy]

just got back from my daughters 3rd b-day party...still can't get the bottom hose off. i know i can not put a lot of pressure due to the inlet so i keep pulling, twisting, grunting and nothing just not a lot of space to work and get a good pull

ps just took out the battery to get more room and still can not budge the hose. i am afraid to put any more pressure on the hose because i don't want to collapse the input feed. i even tried putting an allen wrench between the inlet and hose to loosen things up but nothin'

I apologize for not reading the whole thread but is this the hose you are trying to get off? If so, be sure you remove the metal "U" clip all the way. Then get a long piece of wooden dowel rod. Use the dowel rod and a light hammer to tap downward on the lip to break the connection loose. It will help to file the working end of the dowel rod a little to get a better overlap on the flange.

[dewey527]

no problem old guy. it finally came off with enough brute force, twisting with pliers, prying...did the flush and really brown water came out and some sediment, actually put some natural degreaser in and let it sit for 20 minutes flushed about 5 gallons through the system both ways. have heat but only on manual setting when the middle vents are selected. when i use auto it blows luke cold/warm air. so still trying to figure that out. did bleed the system when car was running using the bleeder valve, but didn't help.

[dewey527]

the problems continue...had heat for a couple of days then cooler air began blowing. added some coolant, bled the system again and i get heat only sometimes when i use the manual setting. how the hell do you bleed the system to get all the air out or what else is the problem?

[absolutegtr]

/\ Is there oil in there? Or is that regular dexi-cool the (pink stuff) with a bad camera setting?....It looks brown

[dewey527]

/\ Is there oil in there? Or is that regular dexi-cool the (pink stuff) with a bad camera setting?....It looks brown

no - iPhone camera and just dirty and the regular pink stuff...fyi i did not flush the whole system but after what i found i probably should.