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dbaker9323

Heater Core Replacement - 65 RIV 401

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Help!  My Mechanic tells me that my heater core on my 65 Riv (401) is totally blocked and needs to be replaced.  I have observed that the heater core encasement appears to be visible on the firewall;  the mechanic states it is not required to disssemble the dash board and go through the interior; rather it can be replaced from the engine side of the firewall.    Please advise.  

 

I would also like to know the best place to purchase a new heater core.  I have only been able to locate one online on ebay but thus far not directly from a distributor or manufactor.  Or is it necessary to have it recored?

 

 Thanks.

 

David Baker #14360

front dr quarter 65riv.JPG

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You got hit. The bane of first gen. ownership.

 

Hold on, the first gen. experts will respond soon....

 

BTW, that is one sweet ride. Are you gonna sell your boat tail to pay for the first gen. repair?  Just teasin'

 

 

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                              The factory intended for it to be serviced from inside the car but I wouldn't do it that way. People who have done it

claim that you can remove it from the engine side of the firewall if after removing the cover on the firewall if you take a cutting wheel

and enlarge the opening a little. I still have my original heater core and it is fine so far, but if it ever starts leaking I'm going to remove it

from under the hood. My plans are to take advantage of the situation if it occurs to detail the sides of my engine block and detail the oil pan,

(my engine has never been apart or removed from the car) so I will just yank the engine, put it on a stand and then I can go to town on the heater core from

under the hood very easily. It's way easier to R and R the engine than it is to tear the dash all apart. I could have the  engine out in an hour and a half. the worst thing about doing it from the inside of the car is that the defroster duct is made of a material that crumbles to dust

when you have to disturb it, then you have to spend hours and hours fabricating a new one. If I eventually have to change my heater core, I will document the procedure to remove it from under the hood....nobody has done this yet. Because of the aluminum timing cover and

thermostat housing and nightmare heater core job, it is imperative that you replace the coolant on these Rivieras every two years and don't

let the cooling system get low or lose it's anti-corrosive additives. this has been done on my car since it was new, and neither the radiator

or the heater core have ever been removed or leaked or gotten corroded or stopped up. It tells you to do this right in the service manual. The original owners of my car were dealership mechanics and they knew how important it was to maintain the coolant on these cars.

Edited by Seafoam65 (see edit history)

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Very difficult job. Most go through the console.  Your mechanic says it's blocked, but is it leaking? I had a bloccked heater core on a different vehicle once and the mechanic reversed the hoses and it flushed itself clean.  Might be worth a try. Easier to do toward the front other engine too. The hoses are different diameters so if I were you, I'd buy some extra hose and use some reducers to make it easier to deal with, no cutting or stretching of the good hoses.  Somewhere on this forum, there's info on filters you can put on radiator hoses.  If you can flush the heater core, you might be loosening up some junk that you need to trap before it gets into tne radiator.

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1 hour ago, Seafoam65 said:

 If I eventually have to change my heater core, I will document the procedure to remove it from under the hood....nobody has done this yet.

Winston,

Just thought I would mention it, the under the hood method has been documented, it is listed in the Technical Tips in the Members Only section of the ROA website.

 

David,

Since you are an ROA member you can go to the "Technical Tips" section of the ROA website and it gives details for the different methods to change the heater core. The following "Tips" are listed ...

 

2. '63-'65 Heater Core Replacement - Inside Method

3. '63-'65 Heater Core Replacement - Under Hood Method

4. '63-'65 Heater Core Replacement. GM Service Bulletin, May 21, 1965

 

I was thinking the under hood method had been posted on here at one time but I am not certain?

 

As far as buying one I believe your best bet is having yours recored? From what I have heard the replacements that are for sale don't fit, so a recore is the best way to go. Perhaps a more experienced member will comment about this?

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I dunno.  I replaced a leaking heater core a few years back (got the replacement from Advance Auto).  I don't remember it being a bad job at all -- but I can't remember if I went in from the inside or outside.  I think it was outside, because I do remember mucking about with the blower box for some reason.  I do not remember cutting the firewall, though.

 

If the core is plugged rather than leaking, you might take the earlier suggestion to flush it first.  Different vehicle, but I had a heater that was rapidly careening towards uselessness.  Disconnect both hoses, then repeatedly flush from both directions.  The first shot blew out a big belch of dark brown water, then subsequent squirts kept getting cleaner and cleaner.  10 minutes later, it was working like a champ.

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15 minutes ago, KongaMan said:

I dunno.  I replaced a leaking heater core a few years back (got the replacement from Advance Auto).  I don't remember it being a bad job at all -- but I can't remember if I went in from the inside or outside.  I think it was outside, because I do remember mucking about with the blower box for some reason.  I do not remember cutting the firewall, though.

 

If the core is plugged rather than leaking, you might take the earlier suggestion to flush it first.  Different vehicle, but I had a heater that was rapidly careening towards uselessness.  Disconnect both hoses, then repeatedly flush from both directions.  The first shot blew out a big belch of dark brown water, then subsequent squirts kept getting cleaner and cleaner.  10 minutes later, it was working like a champ.

An even better idea! Flushing it so that the water is not circulating through the block and radiator seems like a really good idea. ?

 

 

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2 hours ago, RivNut said:

Very difficult job. Most go through the console.  Your mechanic says it's blocked, but is it leaking? I had a bloccked heater core on a different vehicle once and the mechanic reversed the hoses and it flushed itself clean.  Might be worth a try. Easier to do toward the front other engine too. The hoses are different diameters so if I were you, I'd buy some extra hose and use some reducers to make it easier to deal with, no cutting or stretching of the good hoses.  Somewhere on this forum, there's info on filters you can put on radiator hoses.  If you can flush the heater core, you might be loosening up some junk that you need to trap before it gets into tne radiator.

 

Going thru the firewall is a lot easier ! Less chances of breaking a number of small parts . Call me anytime and I will walk you thru it . For a filter I use a kit made for Jaguar , google Jaguar coolant filter . It  is placed within the upper hose . Inside a cup is a screen and the cup has a screw on cap to clean the screen .

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I saw a recommendation for a cheap DIY coolant filter made from a couple of hose barbs and one of the screened washers that you find on a washing machine hose.  Cut your heater hose, insert the barbs and washer, crank it down and clamp it up.

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OK Riviera People: I've disconnected the heater hoses from the core and blown it out with a pressure washer. Lots of black caca came  out. Worth a shot. Mitch

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11 hours ago, KongaMan said:

Disconnect both hoses, then repeatedly flush from both directions

I cleaned out the heater core on my 68 using this method after removing both hoses from the feed lines. I also lubed the heater core box controls where the control cable attaches on top of the firewall box controls because they were no longer functioning when I adjusted the temperature wheel on the controls. I am getting nice and hot air into the cabin now when needed. :)

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                         I agree with Mitch, at my shop most of the time we can unclog a clogged core by back flushing if we spend enough time

doing it. One problem I see though is it is very likely that once the crud is removed from the core, it is liable to start leaking. the fact that it is

plugged up indicates that the cooling system was neglected for a long time.

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Just replaced mine. Did it the "correct" way, which was insane. I don't understand why Buick designed it that way, when it's pretty easy to remove it from the engine side.

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9 hours ago, lrlforfun said:

OK Riviera People: I've disconnected the heater hoses from the core and blown it out with a pressure washer. Lots of black caca came  out. Worth a shot. Mitch

 

I considered using a pressure washer, but I decided it was too risky.  Specifically, repeated blasts of high pressure water might be a little too much for 50-year-old solder joints that have been vibrated for decades and potentially weakened.  Doesn't do you much good to turn a plugged core into a leaky core. ;)

 

I did come up with an "automatic" flush system, though.  Start with a small sump pump in a bucket of water.  Connect the outlet of the pump to the heater outlet hose.  Run the heater inlet hose back into the bucket.  You hook the hoses up this way to do a reverse flush rather than further compacting any blockages.  Turn on the pump and let it run.  The theory is that the constant flow of water will flush out all of the loose or lightly attached debris.  In practice, I'd probably blow the initial (dirtiest) waste water somewhere other than the bucket so that the debris doesn't get recycled through the pump and core.  You could also also put an inline filter (e.g. washer hose) on the line to trap any subsequent debris that breaks loose.

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Thanks to all of  you who replied!  Not sure which method I will decide upon, but I am leaning to under the hood after reading the GM service bulletin for removing it from the cabin!

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First thing I ever did to mine was replace the core by taking the dash apart. Not fun but I've also done way harder modern cars where the core and the evaporator are in one unit.

 

Recently just got the car out of storage and a coolant flush along with a correct '63 heater valve were installed. So even though it doesn't have A/C, at least it won't fry my feet with vent air passing over the hot core.

 

 

Edited by jimtash (see edit history)

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What a great chance to develop a more casual acquaintance with your mechanic. Flush it out yourself first. It is messy, but will give you some intimate knowledge of the car and a bit of confidence.

 

If you can't unplug it I don't think you need much larger than a 1/2" socket and a couple of screwdrivers to change the core. It just takes patience and organization.

 

I am curious about the diagnosis. Did he disconnect the heater hoses and try to push water through? Seems like he would have said "When I didn't get flow I tried to backflush and couldn't force anything out." I did say that?

 

How would you like to go through a core replacement and find out the heater valve failed or a hose delaminated? Those are things that get you a phone call "I found something else." I am not a very trusting soul, but I was trained to be that way.

 

Are you in western New York? Maybe you just need someone to come over and sit on a bucket while you work. I point and grunt pretty good.

Bernie

Edited by 60FlatTop (see edit history)
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Hi David,

 

I did mine last year in my ‘63.

 

If they are the same as 65 then they are not difficult, but just time consuming. I took lots of photos along the way and had to clean and refurbish and renew bits as I found them, which consumes lots of time. (Just waiting for bits to arrive takes time)

 

I removed both seats and carpet and console, distributor and cover on the firewall. It is great practice for being a contortionist as some of the Fasteners are not easy to get to.

 

And if the floor pan is rusty, gives you an opportunity to clean it and repaint it and new sound deadening and underlay and ......

 

And I had a radiator guy repair and test my core which was plugged and leaking but was still a sound Harrison unit. That way I knew all my efforts would not have to be repeated if an inferior aftermarket replacement failed. Cos I don’t want to do it again,

 

Or you could take it to a Buick dealer as the repair time is only about 8 hours or so (ha ha)

 

The ROA gives details of both methods that you can print out. One is where you cut a bigger hole in the fire wall and pull it out that way or the traditional way is where you take out the console.

 

Because you end up removing lots of other bits to get to it, the job can seem quite daunting. But just do one thing everyday towards it and keep focused. 

 

Once you have done it you get a badge and tee shirt which says

 

”I removed and replaced the heater core in a first generation Riviera and survived (just) to tell the tale.”

 

??????????

 

 

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David,

 

   Remove the heater hose at the heater control valve going back to the heater core. Next, remove the heater hose from the water pump. MUCH easier to do it this way rather than trying to disconnect the hoses at the core. Someway, somehow connect your garden hose to the hose from the water pump. This will "Reverse" flush the heater core. DO NOT TURN THE HOSE ON FULL BLAST at 1st. Turn it on slowly so that if it is CLOGGED you will not over pressure it & CREATE a leaking heater core. After the water starts to come out clean you can increase the pressure as the core will no longer have a restriction. You can also try the correct routing, but it shouldn't change IF it was clear/clean. Then if you have a compressor or can borrow one give it a few blasts of air. Not real high pressure at 1st. Then increase pressure as it becomes more clean/clear. Then hook up the garden hose again & do it reverse flush again. The air will loosen up more debris & the reverse flush will get the rest out.

  I don't LIKE using a pressure washer because it can & sometimes causes an otherwise good/OK core to start leaking.

  Just my 2c worth.

 

 

Tom T.

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You can connect a garden hose to a heater hose using one of those hose repair kits with a barb on one end and a female hose connector on the other.  As a practical matter you don't have to go that far.  I used a cheap, small nozzle that I had around (about $2 at Home Depot)and just stuck it inside the hose.  Of course, that tends to be a bit messier. ;)

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It would take a pretty hellacious clamp to make a watertight connection between a 1/2" nozzle and a 3/4" hose. ;)

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If you own one of these cars long enough, you'll have a heater core story to tell.

 

I bought my '65 way back in 1983.  It was my daily driver for ten years.  For the first 5 years or so the heater worked just fine.  But then, gradually, it became less and less effective.  This was so gradual that I learned to live with it.  Oh, it was no fun on sub-zero days, waiting for some merciful heat to invade the cabin.  The only worse thing was a constantly fogged up rear window on damp cold days, as car does not have a rear defroster fan.  

 

Funny thing was, although my heater core was obviously plugged, it never leaked inside the car.  After I retired my Riv from daily service (I had a baby coming and was spending over $200 per month on gas in 1992) I didn't much worry about lack of heat as I used the car mostly during the warmer months.

 

Years later I undertook the restoration of my Riv.  It was time tor finally replace that darned heater core.  I did it as others here suggest - through the firewall.  You need to enlarge the hole in the firewall to get the darned thing out of there.  All this was made easier as I had the engine out to be rebuilt.  I used a pair of tin snips ("nibblers") to cut the firewall steel to enlarge the hole.  The cut areas aren't visible once you put everything back together, so no big deal.  

 

After I replaced the heater core I was amazed at the difference.  Now I can dry tobacco and roast chickens in there!

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If you want to make another beneficial change to your heater system, rewire the blower controls.  In the stock setup, the heater/defroster high setting is the same as the A/C medium setting.  Pop the controls out of the console, move a couple of wires around, and you can have full blow for your heater and defroster as well.  For more details.

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