CLR meets heater core- finally did it
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  1. #1
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    CLR meets heater core- finally did it

    After seasons of doing water flushes with less than marginal success, I finally got the guts up to try CLR. I figured it would either fix it, do nothing, or destroy the core. Anything is a good alternative to disassembling the dash.

    So, this morning on the way to work, I cranked the heat and held my hand to the dash vents. Within a minute, it was uncomfortable to keep my hand there. Think I got it. I'll keep you posted.

    Here's what I did. I got a long piece of heater hose and cut about 2 1/2 feet from the end. I attached this to the inlet and the remainder, which was about 5 feet, to the outlet. I then pumped water through the core to get out any coolant. Not sure that this was necessary, but I figured water would only dilute the CLR and I wasn't sure what coolant would do. I then sucked out as much water as possible with a wet-dry vac. The shorter hose, being previously coiled, stood straight up on the end. I coiled the other around the hood strut like a snake. I then poured in as much CLR as would fit. The whole bottle won't go in right away, but the level eventually drops as it begins working. I then did a process I call oral pulsation. I sucked in a little on the longer tube to draw the fluid in and then let it go back and then in again. I repeated this for about three minutes every 20 minutes. BIG WORD OF CAUTION. DON'T GET TOO ENTHUSIASTIC. CLR HAS AN ODD LEMON LIME TASTE, BUT STINGS. PRETTY SURE IT'S POISONOUS TOO. Take it easy on the suction and keep a big jug of water nearby just in case. I kept the CLR in for an hour and then sucked it out with a wet-dry vac. It will foam like crazy. Once I had the CLR out (and my vac was full), I continued with a water flush in both directions. I think switching flow directions frequently is the most important part. I flushed for a half hour which gave me plenty of time to clean the leaves out of the bulkhead with the overflow.

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  3. #2
    $t0rm1n n0rm@n
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    I still need to try this for I have a bad feeling my core is leaking now.

  4. #3
    $t0rm1n n0rm@n
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    Oh, Also I say after a few have placed comments on this....We should add this post to Jay's write-up in the info section.

  5. #4
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    Let's give it a little time before putting it in the info base. If the heat keeps working and the core doesn't disintegrate in the next couple months, sounds fine.

    If your core is leaking, this may make it worse. I've has good luck with those rabbit pellet things for coolant leaks in other cars.

  6. #5
    $t0rm1n n0rm@n
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    Quote Originally Posted by TwoManyPassats View Post
    Let's give it a little time before putting it in the info base. If the heat keeps working and the core doesn't disintegrate in the next couple months, sounds fine.

    If your core is leaking, this may make it worse. I've has good luck with those rabbit pellet things for coolant leaks in other cars.
    Hmmmm...OK. Cause I seem to lose coolant a good bit in the winter time and every 3 months I need to clean my windshield to help with fogging (all seasons).

  7. #6
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    Quote Originally Posted by TwoManyPassats View Post
    ...I then did a process I call oral pulsation. I sucked in a little on the longer tube to draw the fluid in and then let it go back and then in again...
    oh really

  8. #7
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    LOL, I hope no one saw you doing this. It would look mighty strange to a passerby.

    Whatever works, I guess.

  9. #8
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    Here's some light reading for just after the first cocktail. Check out section 6, particularly:

    http://www.setonresourcecenter.com/m...5/wcd025c3.htm

    (Serious disclaimer: if you're this far out, I wouldn't be too worried)

  10. #9
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    Quote Originally Posted by pson View Post
    Hmmmm...OK. Cause I seem to lose coolant a good bit in the winter time and every 3 months I need to clean my windshield to help with fogging (all seasons).
    Your core IS leaking; no question. Voice of experience talking here.

  11. #10
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    Quote Originally Posted by scotts13 View Post
    Your core IS leaking; no question. Voice of experience talking here.
    He's right.

  12. #11
    $t0rm1n n0rm@n
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    Quote Originally Posted by scotts13 View Post
    Your core IS leaking; no question. Voice of experience talking here.

    It is slow and right now doesn't bug me too much. Hopping I am wrong and will try the pellets try above.

  13. #12
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    My first and last heater core was in a 14 year old 1975 Opel 1900. Bloody mess to do.

    There is still not a lifetime coolant for any auto, so just bite the bullet and replace the stuff every two or three years.

    You will be rewarded by having time to worry about other things.

  14. #13
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    pson

    The pellets are made of shredded ginger and can be found at any old school auto parts store. They're about an inch around and an inch tall. You drop them in the tank and it dissolves and magically finds small holes and expands.

  15. #14
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    First of all, TwoMany, congrats on finally taking my suggestion of CLR (I posted it a long time ago) but, I had suggested using 50% solution and not leaving it too long, the copper and brass come out looking pretty shiny! Next, I only use the gravity feed method, then the very thorough flush. I wouldn't ever get that stuff near my mouth!

    Second, pson, most of the radiator stop-leak products are basically : ta-da- black pepper! Old hot-rodders have used this stuff since way back for temporary stop-leak that actually can be a permanent seal. I don't know if it would be a good idea on the heater core, but the stop leak will only plug a pretty small hole.

  16. #15
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    Quote Originally Posted by Passit+miata View Post
    ...but, I had suggested using 50% solution and not leaving it too long, the copper and brass come out looking pretty shiny!.
    X2 on that. Note that the label on CLR specifically recommends against using on aluminum, copper or brass. I've learned from experience that prolonged exposure can seriously damage metals. Label says two minutes, max.

  17. #16
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    I know about the copper-brass warning, but after I tried everything on the heat exchanger in my home furnace years ago (the hot water coil in the boiler), which was clogged almost solid from hard water, I decided to give the CLR a try. The coil was made from copper with fins inside it. I was quoted almost $1000 for a replacement (with labor) so I figuired I had nothing to loose.

    I filled it with the CLR full strength, let it sit an hour, then flushed from both directions. It worked pretty good, so I did it again, and bingo! Full flow and really hot water. Now I do it for about 15 miutes once a year and never have a problem.

    So then I tried it on the Passat, just before a TB service. The heater core had been just adequate. After an hour of 50% solution soak, then flushing, the inside tubes of the core looked shiny, and a bit of gunk got flushed, but it must have dissolved something, because I have hot air and no problem since, using only Pentosin coolant now. That was back at 85k, and I have 178k now and am going to do the TB again before winter.

    I was hesitant to recommend this at first, but when I read a few owners who were desperate to try something befor having to replace the heater core, that's when I posted. If you don't have leaks, it's worth trying to unclog. If you have leaks, you probably will need to replace the core.

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