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Old 09-17-2014, 11:10 PM
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2010 WK 5.7 - Heater Core Leak

I know there are a few threads like this out there, but I thought I'd start my own and not hijack someone elses...

I have 2010 WK 5.7 and have had an ongoing leak for about a month now in the driver's side footwell area. First noticed it after a long drive (3+ hours) and took it to the dealer to be fixed. They couldn't replicate the leak and the coolant system held pressure for 3 days (obviously it wasn't running but just had the pump on the radiator cap to increase the pressure). So from that they recommended to flush the system.

Two weeks later it hasn't leaked unitil last weekend after another long drive (3+ hours). I've since replaced the radiator cap (no real indication on why to do that other than it's a $5 part so why not). Hasn't really leaked much in the last 4 days but the dealer gave me a quote for $1700 to replace the heater core (labor to remove the dash is the majority of the cost). As you can imagine, I'm not doing that.

I found a video on youtube showing a way into the dash from the passenger side and just needs a few metal brackets to be drilled out (and then reinstalled with some bolts). It looks like once the dash is opened up, the heater core in/out lines are removed, and the metal dash brackets are moved out of the way, the core should just slide right out (towards the passenger side).

Has anyone had any experience with this approach? Does anyone know if the core is attached anywhere else (I'm assuming it just slides in there)?

It should be an easy enough job. I've tried to think through the steps required (not overly detailed). Let me know if anyone thinks of anything else I'm missing.
1. Disconnect negative battery and open up dash by removing glove box and a few other panels.
2. Gently peel back the panel enough to get to the heater core area.
3. Drill out the spot welds on the 2 metal dash brackets and move them aside.
4. Unclamp the hoses from the engine side of the firewall that connect to the in/out feeder lines.
5. Try not to lose too much coolant and plug the two rubber hoses that were disconnected in step 4.
6. Unbolt the brackets holding the heater core lines to the underside of the dash and the 1 bolt holding the heater core lines to the heater core.
7. Remove the heater core lines while trying to not leak coolant all over the floor.
8. Pull out heater core.
9. Insert new heater core.
10. Install new o-rings and heater core lines to core.
11. Attach heater core brackets to underside of dash.
12. Unplug heater core hoses under the engine and reattach to feeder lines through the firewall.
13. Fill overflow reservoir to fill line.
14. Run engine for 15-20min and allow it to heat up.
15. Turn off engine and let cool for a few hours.
16. Repeat steps 14 and 15 a few times until the reservoir isn't emptied during the cooling phase.
17. Reinstall the metal dash brackets with bolts and locking washers.
18. Reinstall dash panels.

If I understand correctly, the system should "burp" itself free of any trapped air during the heating and cooling cycles. But I could be wrong on this. I'm trying to avoid draining the whole system because I don't think that's necesary especially since I just had it drained and cleaned. Once I'm happy with the results, I'll reinstall all of the dash components.

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Old 11-04-2014, 11:38 AM
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Re: 2010 WK 5.7 - Heater Core Leak

No experience but I will be trying it in the next week. Did you go ahead and replace this way?
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Old 11-04-2014, 12:04 PM
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Re: 2010 WK 5.7 - Heater Core Leak

I replaced it like this about a month and a half ago with little to no issues. Really the hardest part was getting a drill in to drill out the spot welds. I'll admit that I mangled the brackets a bit but I was able to situation a few bolts in there at the end of the day to hold it in place. No one will be able to see it anyway.

It turned out that the heater core was okay (or at least I think it was okay). The problem ended up being a small pin hole leak in one of the feeder lines right before it enters the heater core. I never would have seen it without detaching the lines from the heater core. I ultimately had to use a flashlight in the line to even see the hole.

I ended up replacing the heater core anyway along with the lines. Once those lines are out and the brackets are out of the way, the heater core literally just slides right out with pins, clips, bolts, etc. holding it in.

No issues since the install and it probably took me about 3-4 hours including take apart and putting the minimal dash pieces back together.

I think I paid less than $200 for all the materials below (quite the savings from what the dealer wanted):
-heater core $67
-lines $56
-coolant from dealer $30?
-new o-rings for lines from dealer $10?
-random rubber stoppers from hardware store to plug lines at firewall $10?

Make sure you get the o-rings since they don't typically come with the heater core or lines and they are likely going to need to be replaced.

Best of luck
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Old 11-06-2014, 04:40 PM
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Re: 2010 WK 5.7 - Heater Core Leak

The heater core can be done and should only be done doing the cheater method. You might need a 2nd person to hold some of the plastic parts back. Don't worry the plastic the dash is made out of is super strong.

Be sure to replace your lines that go to the core as mine were pitted as well and it makes sense to go in there and do them while doing the core. Try and buy quality parts as you don't want to have to mess with it again. Duct tape works wonders holding the cut part of the dash back together.

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