Replacing Heater Core

[Glasact]

Turned on the heater this morning for the first time on my '00 LS2 and noticed the sweet smell of antifreeze, (not a good thing). I got home and started checking it out. My heater core appears to have a build up of corrosion and gunk on it along the bottom. I suspect the previous owner may have added a sealent to the coolant to stop the leak and it has formed this gunk where the leak was. There is no wetness or staining on the carpet but I'm taking no chances and will be installing a new core soon. It looks to be a fairly easy job but I do have one question. I'm old school and have never worked with the kind of connections I see to the core. Do I need a special tool to disconnect and reconnect the fittings? What ever happened to band type hose clamps with a screw you just tighten? Hey they worked!!

[Chriscnl]

No not really the clip that goes around where the pipes connect to the heater core just need to be undo and you can pull the pipe out from the heater core.

[fdryer]

You can't be old school if you can recognize a strange looking clamp; although I have an FSM for '02-'03 L-series vehicles I'm guessing the clamps on mine are similar to yours. If they are, then the FSM describes them to be quick connect types where the release tab is located at the 6 o'clock position. Something like pressing on the tab, pulling back the collar, and pulling the quick connect coupler off the heater core tube along with the hose. There will probably be some twisting, pushing and pulling in any combination of directions until the hoses become unstuck, to use the vernacular, for you to successfully remove the hoses. I guess you'll have to save the worm clamps for another day unless these plastic resin type hose connectors crack from the combination of UV exposure and age.

[Glasact]

Thanks for the quick response! My nearest Saturn dealer (Huber Heights) said he allways keeps a core in stock. $205.16 +tax. Not too bad I guess. Looks to be about a two hour job tops, including beer breaks! I'll advise as to how it goes.

[Glasact]

I replaced the heater core last night. It was in worse condition than I expected to find it. (see picture) I'm very suprised I didn't have a flood on my passenger side floor. The job takes less than two hours and is a DIY for most.

Some words of caution when doing this job yourself.

1. THIS ONE IS IMPORTANT!
Make sure the car is safely on jack stands before getting under the car to drain the radiator!

2. The splash shield has (5) five screws to remove. Three on the bottom & two in the wheel well area. One screw in wheel well is accessed through a hole in the inner fender. (see picture)

3. There will be coolant remaining in the lines when you disconnect the heater core. Be sure to have a thick layer of towels under the area to catch it! I used my wet vac, and extracted another quart or more of coolant from these lines along with the core.

4. Make sure both lines are held back out of the way when you install the new core. You don't want to damage the new heater core, or the lines by dragging it past these lines.

5. Seat the new core in the cavity carefully. You will know it is located correctly when the white nylon retainer lines up with the screw hole. Install the white backing rings on the lines 1st, & then the black "O"-Rings.

6. Use a lubricant that is safe for "O"-Rings and apply to the openings where the lines go & also to the "O"- Rings. The lines just push into the heater core openings. Install your new quick disconnect retaining clips around the line connections.

7. (This is a good time to completely flush your cooling system.)
Refill the cooling system. USE DEX-COOL ONLY!!! 50/50 Mix. Run the heater on high untill HOT heat is observed. Continually check for leaks while the car is running. When you are satisfied everything is good, button it all back together and pat yourself on the back. You just saved yourself a bit of change.

8. For the next several days, keep an eye on your coolant level. As the air is squeezed out of the system, you will likely have to add more coolant. You may have to add a couple of times.

[Glasact]

"Ooooppps!

Forgot to add the pictures in my previous post!

Here they are.

[GregS&L]

^^^^Thanks all for the posts on replacing the heater core. This does not seem to be a long and difficult job. I will copy this one in case I need to do this on mine further down the road.

The last heater core I replaced was on a 1980 Ford T-Bird. What a Bee! The entire dash had to be removed to get at the core. Took me over an entire day for the effort!

This looks like a piece of cake in comparison. Thanks again.

[srponies]

I might add the suggestion to just pinch closed the 2 heater core hoses running from the back of the motor to the firewall. Use some wood clamps, C-clamps and/or flat vise grips. Then put your drain pan under the hoses at the firewall. Proceed to disconnect the hoses at the firewall and then R&R the heater core. You might get a small bath - but it's not as time consuming as dropping the splash shield and draining the radiator and all A/F. Besides - the heater core sits so low that it's hard to drain those rear hoses anyhow. Now if your flushing/replacing all the antifreeze with new - that's a different story.

Good luck,
Steve H.

[Varagon]

Were any of you able to find the quick connect clamps and O ring replacement parts?

Mine are leaking at the heater core and should be an easy fix, but I can't find any replacements...