HOW-TO: Heater Core Flush

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HOW-TO: Heater Core Flush

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Blazer >> Mechanical & Maintenance >> Do-It-Yourself >> HOW-TO: Heater Core Flush

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HOW-TO: Heater Core Flush - 3/25/2008 5:54:23 PM

a_tack

Suspension Tech Moderator
Posts: 1287
Joined: 4/5/2006
From: Ashland, Kentucky
Status: offline

Heat not working? Do you find your heater blowing out cold air? Do you find yourself driving around freezing all the time? Your Heater core may be plugged. A clogged heater core or low coolant level can cause the heat in your Blazer to stop working temporarily. There is a quick and easy way to fix this problem using no special tools until you have the time or money to do a complete coolant system flush. Dex-cool, over time, if not taken care of can solidify and clog small openings in your cooling system. The heater core is usually the first to plug up. Keep in mind this fix is temporary only. If you do not do a complete system flush you will find your heater core plugged up again in a matter of 6-12 months. I would highly reccomend a full system flush, but if you need heat now try the following.

Tools Needed:
- Pliers, channel locks, vice grips, or any form of pliers.
- Water hose
- Adjustable water hose nozzle
- Safety glasses

Step 1:
Park your truck on a relatively flat surface. Pop your hood and leave it up, giving the engine and cooling system sufficient time to cool down. I usually gather my tools and other equipment while the truck cools. Cooling may take over an hour depending on how much the truck has been driven on the day you do this. As always, safety first. Make sure you have a good set of safety glasses as to not get coolant in your eyes.

Step 2:
Locate the two heater hoses that attach to the heater core on your firewall.

Step 3:
Using pliers (i prefer vise grips because they lock with the spring compressed) compress the clamps that attach the heater hoses to the inlet/outlet of the heater core.

After comperssing the rings, slide them back on the hoses and pull the hoses off. It may take a bit of force, but not too much. You do not want to break them. There is no need to mark the hoses because they are different sizes.

Step 4:
Using your water hose and a spray nozzle, you can begin to flush the heater core. First set the spray nozzle to jet. Place the head of the nozzle to the inlet and spray water. At first the water that coumes out the outlet will be reddish brown and may contain sludge.

Continues to spray water until it comes out clear.

Now, do the exact same thing with the outlet. Spray water in the outlet until the liquid flowing out the inlet is clear. Repeat this process several times until nothing but clear water comes out each side.

Step 5:
Reattach the hoses in their proper place. The bigger hose goes on the passenger side and the smaller hose goes on the drivers side of the heater core.

Using your pliers, compress the hose clamps and return them to their original position.

Step 6:
Make sure you top off you coolant at both the radiator

and the coolant resorvior.

and ALWAYS use a Dex-cool compatible coolant. I prefer the 50/50 pre-mix.

< Message edited by a_tack -- 3/25/2008 6:44:22 PM >

_____________________________

-Aaron