Author Topic: Help Replacing my Heater heat exchanger (Read 18428 times)

dendrinos · « **on:** June 10, 2007, 19:23:23 »

I have been in the process of replacing the heater control levers on my 69 280sl. In the process I thought I would also replace the air intake filter . in getting to that I see that the seal to the fresh air flap could stand to be replaced as well.

Digging deeper still I see what looks like a side wall to the heat exchanger has broken off and is just sitting there. So I guess I am going to replace that as well. And here is the question;

Does anyone have experience with that replacement? How do I get it out of there? Are there things I should be watching out for while doing this replacement? Or perhaps other things I should also replace at that time?

Also I notice that all things foam related have disintegrated in and around the heater / air flow system. I’ll replace the defroster nozzle seals, but are there other seals not in the SLS breakout sub section 83 I should be replacing?

The thing is while I’m in there, I might as well do it right, and not have to go back in later to redo something.

Thanks for any input. Oh is there a better place in the USA to get these items than going to SLS? I don’t have a problem with it, but perhaps I can save a buck, or even some time in transport.

I guess it's worth noting that the car does not have ac.

Thanks

Pete

280 Sl
Michigan, USA

Rolf · « **Reply #1 on:** June 10, 2007, 21:13:55 »

Have you tried Bud's Benz? http://www.budsbenz.com/catalog/200

Rolf
1966 230SL Auto
1992 300D
1991 FLHS

DavidAPease · « **Reply #2 on:** June 10, 2007, 23:58:53 »

Hi, Pete,

I believe that changing the heat exchanger (heater core) is a pretty major undertaking. It is fairly common for the guard piece that you found to come off the side/top of the core, and as far as anyone in the group has reported, it is fairly innocuous. It's probably unnecessary to dive into the heater core just because of that piece, and only replacing the foam/rubber bits might be a lot easier. Of course, if you want it to be perfect...

-David Pease
'66 French 230SL

jameshoward · « **Reply #3 on:** June 11, 2007, 04:48:20 »

Pete,

Not sure what you mean by a 'side wall to the heat exchanger.' If you mean that there is a thin metal sheet bobbing around alongside the heater core, this is just a back plate for the element. It's not uncommon for them to fall off and just sit there. Mine is the same, and the advice I had was simply to remove it and not worry about it. I haven't pulled it out yet, but I intend to. There are other posts about it on the site, but you needn't worry about replacing it. Assuming, that is, that we're talking about the same thing!

(I have some photos somewhere if you need one to confirm)

JH

dendrinos · « **Reply #4 on:** June 11, 2007, 04:59:35 »

While i have seen buds mentioned here before, i have never found a link or their web site. Thank you for the information. They are a reputable shop?

Pete

quote:
Originally posted by Rolf

Have you tried Bud's Benz? http://www.budsbenz.com/catalog/200

Rolf
1966 230SL Auto
1992 300D
1991 FLHS

280 Sl
Michigan, USA

dendrinos · « **Reply #5 on:** June 11, 2007, 05:06:25 »

I am funny that way. It will bother me that there is something not quite right, and i have done nothing about it. Ignorance is indeed bliss!

The foam on the heat exchanger housing is also degrading to the point of sloughing off. I could kill two birds with one stone as it were.

quote:
Originally posted by DavidAPease

Hi, Pete,

I believe that changing the heat exchanger (heater core) is a pretty major undertaking. It is fairly common for the guard piece that you found to come off the side/top of the core, and as far as anyone in the group has reported, it is fairly innocuous. It's probably unnecessary to dive into the heater core just because of that piece, and only replacing the foam/rubber bits might be a lot easier. Of course, if you want it to be perfect...

-David Pease
'66 French 230SL

280 Sl
Michigan, USA

dendrinos · « **Reply #6 on:** June 11, 2007, 05:13:04 »

I do believe we are talking about the same thing. As i mentioned below i am a bit OCD (obsessive/compulsive) about stuff like this.

It does look like the tack welds simply broke on the housing. i could almost see a repair rather than a replacement if i could get at it. But then i would still be dealing with rotten foam.

Pete

quote:
Originally posted by jameshoward

Pete,

Not sure what you mean by a 'side wall to the heat exchanger.' If you mean that there is a thin metal sheet bobbing around alongside the heater core, this is just a back plate for the element. It's not uncommon for them to fall off and just sit there. Mine is the same, and the advice I had was simply to remove it and not worry about it. I haven't pulled it out yet, but I intend to. There are other posts about it on the site, but you needn't worry about replacing it. Assuming, that is, that we're talking about the same thing!

(I have some photos somewhere if you need one to confirm)

JH

280 Sl
Michigan, USA

bpossel · « **Reply #7 on:** June 11, 2007, 06:44:52 »

Hi Pete,

Mine was loose also, and I simply removed it.
See more info under this posting...
http://index.php?topic=6028
Regards,
Bob

bpossel (Memphis, TN.)
'71 280SL / '97 E320

jameshoward · « **Reply #8 on:** June 11, 2007, 08:50:07 »

...And it was Bob's thread as attached that confirmed to me it was of little use! (Funny how these things go around - thanks for posting it Bob. I must get mine out as every time I go over a bump I hear it's tinny rattle which is annoying).

dendrinos · « **Reply #9 on:** June 11, 2007, 09:42:34 »

Thank you bob. I looked around but didn't find these posts. I take it from one of the photos that all this was done from within the cabin of the vehicle. Perhaps by removing the housing etc...

pete

quote:
Originally posted by bpossel

Hi Pete,

Mine was loose also, and I simply removed it.
See more info under this posting...
http://index.php?topic=6028
Regards,
Bob

bpossel (Memphis, TN.)
'71 280SL / '97 E320

280 Sl
Michigan, USA

dendrinos · « **Reply #10 on:** June 11, 2007, 14:49:47 »

Bob could you share with me how you got it out of there?

It does not look lie it will come out the top.

Pete

quote:
Originally posted by bpossel

Hi Pete,

Mine was loose also, and I simply removed it.
See more info under this posting...
http://index.php?topic=6028
Regards,
Bob

bpossel (Memphis, TN.)
'71 280SL / '97 E320

280 Sl
Michigan, USA

enochbell · « **Reply #11 on:** June 11, 2007, 15:37:25 »

Pete,

This is pretty serious surgery. When they built the W113 the factory started with a heater core and then built the entire car around it...

Well, maybe not that bad. But you will need to remove the fan box, which requires removing the heater ducts (I think the job can actually be accomplished with these in place, but I would not risk destroying these expensive and fragile pieces). I actually released my wiper assembly to get easy clearance. Again, probably not required but everything is such a tight fit I was being cautious.

As I recall, the fan box needed to slide to the right, into the passenger footwell, to be removed.

Then the only other trick is to access the heater valve control arm through the access hole on the engine side of the firewall. And then, yes, the heater core comes out from the cabin side. While you are at all this, have a look at the archives for how to renew the o ring in the control valve.

BTW, I had the same problem with disattachment and I j-welded mine back together. If you are handy with a brazer you could do the job properly.

Best,
g

'64 230sl, fully sorted out...ooops, spoke too soon

dendrinos · « **Reply #12 on:** June 11, 2007, 20:48:04 »

It looks as though the drivers side defroster duct needs to be detached from the box below it. the passenger is easily removed with the radio and glove box out. however the driver side is another issue. Do i need to remove the tach. and other gages to get at it. Did i hear i may need to remove the steering wheel column as well?

Pete

quote:
Originally posted by enochbell

Pete,

This is pretty serious surgery. When they built the W113 the factory started with a heater core and then built the entire car around it...

Well, maybe not that bad. But you will need to remove the fan box, which requires removing the heater ducts (I think the job can actually be accomplished with these in place, but I would not risk destroying these expensive and fragile pieces). I actually released my wiper assembly to get easy clearance. Again, probably not required but everything is such a tight fit I was being cautious.

As I recall, the fan box needed to slide to the right, into the passenger footwell, to be removed.

Then the only other trick is to access the heater valve control arm through the access hole on the engine side of the firewall. And then, yes, the heater core comes out from the cabin side. While you are at all this, have a look at the archives for how to renew the o ring in the control valve.

BTW, I had the same problem with disattachment and I j-welded mine back together. If you are handy with a brazer you could do the job properly.

Best,
g

'64 230sl, fully sorted out...ooops, spoke too soon

280 Sl
Michigan, USA

George Davis · « **Reply #13 on:** June 11, 2007, 22:37:52 »

This brings back wonderful memories! I don't think I was ever able to get the drivers side defroster duct out, but it isn't necessary to remove it. You just have to remove the two screws that hold the defroster duct to the heater box. Removing the left screw is difficult. I don't think I had the steering column out. The first thing is to try to get your hand in there and find the screw head. If you can find it, you may be able to get a small wrench on it, or a small ratchet and socket, and get it out. It takes some contorting to do it. I think I used a stubby 10 mm ratcheting box end wrench, or else a 10 mm socket and 1/4 inch drive ratchet.

The other fun fastener is the lower fan box mount, which bolts into the transmission tunnel. The access panel has to be removed to get it out, which also requires removing the carpet over the trans tunnel. If the carpet is glued down, it may be damaged in the process.

If you're going so far as to get the heater core out, you end up with most of the dash disassembled, so you might as well repair everything you can while you're at it. It is easier to take it all apart the second time, though.

Good luck with it!

George Davis
'69 280 SL Euro manual

dendrinos · « **Reply #14 on:** June 12, 2007, 05:14:13 »

Thank You George. It's not unusual for me to find myself in protracted situations like this. I'll make the best of it, by replacing lights, gaskets, cleaning things up etc...

Pete

quote:
Originally posted by George Davis

This brings back wonderful memories! I don't think I was ever able to get the drivers side defroster duct out, but it isn't necessary to remove it. You just have to remove the two screws that hold the defroster duct to the heater box. Removing the left screw is difficult. I don't think I had the steering column out. The first thing is to try to get your hand in there and find the screw head. If you can find it, you may be able to get a small wrench on it, or a small ratchet and socket, and get it out. It takes some contorting to do it. I think I used a stubby 10 mm ratcheting box end wrench, or else a 10 mm socket and 1/4 inch drive ratchet.

The other fun fastener is the lower fan box mount, which bolts into the transmission tunnel. The access panel has to be removed to get it out, which also requires removing the carpet over the trans tunnel. If the carpet is glued down, it may be damaged in the process.

If you're going so far as to get the heater core out, you end up with most of the dash disassembled, so you might as well repair everything you can while you're at it. It is easier to take it all apart the second time, though.

Good luck with it!

George Davis
'69 280 SL Euro manual

280 Sl
Michigan, USA

hkollan · « **Reply #15 on:** June 12, 2007, 06:17:43 »

Hi all,

If this problem is "solved" by merely removing the loose piece,
sooner or later the welding on the tube(s) from the heater core going through the firewall will break off.

Hans

'71 '70 '68 280 SL

enochbell · « **Reply #16 on:** June 12, 2007, 06:24:41 »

While you are in that deep, there are a few things you can do that can make a big difference: renew all the bulbs, lubricate the control cables, and clean the inside of the instrument glass.

And be really careful removing the screws that George references, the old heater ducts are fragile and you don't want to rip the attachment feet. And no, you don't need to remove the column but getting the steering wheel out of the way will make things easier.

Best,
g

'64 230sl, fully sorted out...ooops, spoke too soon

dendrinos · « **Reply #17 on:** June 12, 2007, 09:23:07 »

Hans, this is exactly my reasoning. better to do the job correctly the first time than have to come back an redo it later. My objective is to bring this car back to like new condition. I am not too far away.

Pete

quote:
Originally posted by hkollan

Hi all,

If this problem is "solved" by merely removing the loose piece,
sooner or later the welding on the tube(s) from the heater core going through the firewall will break off.

Hans

'71 '70 '68 280 SL

280 Sl
Michigan, USA

dendrinos · « **Reply #18 on:** June 12, 2007, 09:25:15 »

Enochbell, thank you for the ideas, i will indeed look at those items. I imagine that will prompt more questions, but it will be good to know it is done correctly.

Pete

quote:
Originally posted by enochbell

While you are in that deep, there are a few things you can do that can make a big difference: renew all the bulbs, lubricate the control cables, and clean the inside of the instrument glass.

And be really careful removing the screws that George references, the old heater ducts are fragile and you don't want to rip the attachment feet. And no, you don't need to remove the column but getting the steering wheel out of the way will make things easier.

Best,
g

'64 230sl, fully sorted out...ooops, spoke too soon

280 Sl
Michigan, USA

dendrinos · « **Reply #19 on:** June 13, 2007, 12:17:38 »

Another related question, in trying to remove the fan box i am having problem with a bolt.

There are two bolts on the top of the unit that secure it to the frame of the dash and one bolt that secures the base of the unit to the tunnel over the transmission and drive shaft via an L bracket. The problem is that the bottom bolt, the one going though the L bracket and the tunnel appears to have a nut on the other side of it that is spinning with the bolt, and so wont loosen up. Any ideas on how to get at this?

The L bracket gets in the way of removal of the fan box, and apparently must be removed.

Thanks for the ideas

Pete

280 Sl
Michigan, USA

enochbell · « **Reply #20 on:** June 13, 2007, 12:35:15 »

Pete,

I was able to get a small locking plier on the nut by reaching around and above the transmission, ('64 4-speed) but I can't guarantee that will work on yours (?automatic). And, truth be known, I could not reverse the process when I reinstalled, so there is a self-threading stainless screw in there now. Please don't tell Pebble Beach on me.

g

'64 230sl, fully sorted out...ooops, spoke too soon

dendrinos · « **Reply #21 on:** June 13, 2007, 13:40:23 »

Bummer, well ok, thank you for the info. At least i know what i am up against.

Pete

quote:
Originally posted by enochbell

Pete,

I was able to get a small locking plier on the nut by reaching around and above the transmission, ('64 4-speed) but I can't guarantee that will work on yours (?automatic). And, truth be known, I could not reverse the process when I reinstalled, so there is a self-threading stainless screw in there now. Please don't tell Pebble Beach on me.

g

'64 230sl, fully sorted out...ooops, spoke too soon

280 Sl
Michigan, USA

Naj ✝︎ · « **Reply #22 on:** June 13, 2007, 13:47:45 »

quote:
The problem is that the bottom bolt, the one going though the L bracket and the tunnel appears to have a nut on the other side of it that is spinning with the bolt, and so wont loosen up. Any ideas on how to get at this?

I used a long open ended wrench thru the front tunnel aperture.
Put some masking tape on one of the open jaws of the wrench so that the nut can engage tightly and not fall off.
When reinstalling, I put the bolt back from below (stuck on the wrench) and the nut in the cab.

naj

68 280SL

dendrinos · « **Reply #23 on:** June 13, 2007, 14:56:09 »

Yes an excellent solution. I just discovered this port, and used it to remove the nut in question. It had been painted over.

Thanks, pete

quote:
Originally posted by naj

quote:
The problem is that the bottom bolt, the one going though the L bracket and the tunnel appears to have a nut on the other side of it that is spinning with the bolt, and so wont loosen up. Any ideas on how to get at this?

I used a long open ended wrench thru the front tunnel aperture.
Put some masking tape on one of the open jaws of the wrench so that the nut can engage tightly and not fall off.
When reinstalling, I put the bolt back from below (stuck on the wrench) and the nut in the cab.

naj

68 280SL

280 Sl
Michigan, USA

dendrinos · « **Reply #24 on:** June 15, 2007, 05:53:02 »

any advice on a good way to replace the foam seals on these parts. All are deteriorated completely. Through SLS i see the seals for the defroster nozzle, but thats all.

Pete

280 Sl
Michigan, USA

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Author Topic: Help Replacing my Heater heat exchanger (Read 18428 times)

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