Hopefully the Last Heater Core Question

[merrill]

After much valuable feedback from the forum about what to do while I have the dash apart, should I really pull the heater core?
I know this is just a lot of work, but If I am not having problems with it should I just change the valve o ring, lube the lever cables and maybe use a hose to clean the core out?  

I am not adverse to the work, just not sure if I really "need" to do this.  
I guess I am trying to convince my self either way. this is the original core and it 40 years old. If i get it out, have it pressure tested and nothing is wrong then that is a lot of work for nada.

from the posts i have only seen one reply where the core did get a leak.  
I could flush the core via the hoses in the engine compartment.

thanks in advance
matt

[graphic66]

If your that close you might as well take it out. I have removed 2 and both had broken mounts and neede resoldering. It is a lot easier to pressure test, flush, clean, and paint while out. Also the foam pieces sealing it in have probably deteriorated. I used adhesive backed foam tape designed for pickup truck cap to bed gasket to replace it and some other places where the foam had crumbled. Why hold back now?

[merrill]

graphic66,
thanks for the feedback, just for fun i pulled the cover over the heater core valve, and of course there is rust on the fins and green stain close to the valve indicating probably a water leak.

here I go!

[TR]

Matt -- I agree that you should go for it.  My dash is all apart right now.  Just last week I pushed my mechanics to pull the heater core and there was nasty evidence of nearly 35 years of long, slow leakage; it was dirty/clogged with dust, foam molding was badly decayed, a metal band that runs across the top was flopping loose, etc.

Then it was noticed the defrost distribution chambers were a mess where they come up out of the dash.  Then it was noticed that foam molding throughout the entire heater system turned to dust if lightly touched.  Then it was noticed the control cables were stiff.  Then it was noticed the fan motor was weak.  And so on.  You get the picture.  

I mean the last time I used the heater it did work, but not particularly well.  It's in my nature to replace just about everything when stuff is torn down the way mine currently is.  In effect, I'll have a brand new heater system when it all goes back together, and based on what appears to be an improved heater core replacement I suspect the entire heater system will work better than when new.

I know this 'over-the-top' replacement approach isn't for everyone, but I intend to drive this 280SL for decades to come and just figure, "hey, why not(?)".

I sure hope the heater will perform better than when the car was new, because we use the car in crisp & cool Idaho weather with the top down.  Those new seat heaters should help too.  Heh, heh...

Tom in Boise

P.S.  I'm having my guys do almost everything when it comes to stuff under the dash.  This includes stripping off the small amount of pitiful original insulation material and then lining every square inch humanly possible with new DynaMat Extreme sound/heat insulation mat'l.  This involves a lottt of effort, but I suspect the benefits might be worth it.  We shall see.

[ted280sl]

Gentleman,
  After I re-instaled my heater core I was disappointed in the performance of the heater. It seems that the linkage to my heater core was not adjusted properly. I am mentioning this as it is easily overlooked. I was able to fine tune the adjustment of my heater core by conecting the heater core pipe without the adjustment valve to a garden hose and leaving the other pipe open. When the temperature valve inside the car in on blue no water should be passing through the heater core.
Regards,
Ted 1969 280SL

[ja17]

You guys got guts! I would not wish that job on anybody.

Joe Alexander
Blacklick, Ohio

[jeffc280sl]

Thanks Joe,

I have to agree.  I recommend you take the seats and steering wheel out.  Even with them out it's a bear of a job.  Not good for backs, necks and big knuckles.  Having just finished the job and taken the SL out for a spin I can say it was worth it.  Clean gauges, a dimmer that works, a tach which doesn't squeal, a speedo that doesn't bounce and a 72 degree day in DC make for a fine ride.  Heater and blower motor work well to, almost forgot.  I guess it's on to the next job.

Jeff C.
1970 280SL 4-speed

[merrill]

well, thanks for the feedback everyone.
now that I know this is a bear of a job I will really have to get myself motivated....
oh well, once every 39 years isn't too bad..

thx
matt

[pcbenz]

Hello Ted,

My '68 280 SL heater has never been touched since new and since I only acquired it a year ago, never tried the heater until recently. I has poor performance in the 20 degree Kansas weather. Did you adjust the cables by the dash levers? (accessible via the radio speaker?) or in the engine compartment.  Where is the adjustment valve located and accessed?

Thanks,
PCBenz

quote:Originally posted by ted280sl

Gentleman,
  After I re-instaled my heater core I was disappointed in the performance of the heater. It seems that the linkage to my heater core was not adjusted properly. I am mentioning this as it is easily overlooked. I was able to fine tune the adjustment of my heater core by conecting the heater core pipe without the adjustment valve to a garden hose and leaving the other pipe open. When the temperature valve inside the car in on blue no water should be passing through the heater core.
Regards,
Ted 1969 280SL

[jeffc280sl]

PCBenz,

There is no fine tuning adjustment of the heater lever cables  behind the radio.  Maybe one of your cables has come loose and/or one of the air louvers is stuck.  Hard to say.  The heater core valve is accessable from the engine compartment via a firewall plug near the fuse panel.  Remove the plug and you should see the valve open and close (rotate 90 degrees) by using the heater lever.  If operating correctly I think the heater will work fine in 20 degree or lower temperatures.

Jeff C.
1970 280SL 4-speed

[waltklatt]

THe heater core removal and re-installation is not that bad a job.  I've done it several times and get better and quicker each time.  Last time I did it was about 2 years ago on my fintail wagon.  The seal at the spigot valve should be replaced, the brass cleaned out of burrs and congealed antifreeze and grease with steel wool, and the entire thing pressure tested.
Then replace all rubber hoses and fittings and foam insulation to create a tight seal.  With the foam seals replaced all over you will get better heat and fresh air drafts rather than it leaking out all over.  Be extra careful when putting it all back in as there are thousands of bits that all go back together.  Take plenty of pictures/drawings , etc. to help in locating everything.
Lastly, grease up the cables with litium grease to allow free movement, no kinks or bends in the cables or they will be hard to operate.  Clean and lube up the control levers and replace bulbs.  Replace the rubber seal at the top vent(under the cowl and behind chrome grille).  Make sure the drains are clear and no rust in the cavity.
Take no fear or any jitters with the heater core repairs, it's not that big a job.  Compared with doing an engine or transmission rebuild-now that's a job.
The gas to diesel conversion is also not that big a job, but takes inginuity and perseverance and not getting offended by the purists.
Walter Klatt
1967 220SL-diesel-no shame
1963 230SL-gas

[rwmastel]

quote:Originally posted by pcbenz

.... never tried the heater until recently. I has poor performance in the 20 degree Kansas weather.

PCBenz,
I had little heat in my car when I purchased it.  Actually the engine ran too cool in the winter (60C/140F).  The next summer I back-flushed the coolant system, put in new MB coolant/water, and put in a new thermostat.  It's been great ever since.  That's my advice.

Rodd
Powell, Ohio, USA
1966 230SL, Euro, Auto, Leather, both  tops
1994 E420

[enochbell]

LAX,

NOW YOU TELL ME!  I spent over an hour reconnecting the control rod to the valve doing the Pagoda Yoga in the foot well.  Now you tell me I could have accessed it from the engine compartment.  A little more lead time would be appreciated, thank you :-)

g

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

[DavidAPease]

Hi, Greg,

The earliest 113s did not have the access hole in the firewall that allows heater valve access from the engine comparment.  If you have a large rubber plug at the very top of the firewall above the heater core inlet hose, you can reconnect the control rod through that hole.  I'm not sure exactly when the access hole appeared, but your '64 may not have it.

-David Pease
'66 French 230SL

[A Dalton]

FWIW.........

  The regulator valve has a washer on top that slides into a slot of the heater core . It's purpose is to set  the rotatioanal stop limits  for flow control. [ from full Off to full Open] . This washer can be installed up-side down and the lever re-attached to the valve square and the results will be a funtioning valve , but it will not get to the full open position. [ resulting in a heating capacity complaint]
 So, if one takes the hose off the core and looks into the pipe , you will see if this valve is fully opening with the dash lever control.
 This is why it is important to index mark all valve/lever components before R&R of the O ring.

[jeffc280sl]

adding to A. Dalton's comments.  

Underneath the washer you have the cylindrical valve assembly.  The valve itself has an inlet hole on its side. Outlet is through the hollow base of the valve and into the heater core.  The heater control lever will turn this valve approx 90 degrees ( I think clockwise) from off to full open.  If you have removed the valve for cleaning or installing a new o ring you must reinstall it correctly.  By this I mean a closed side of the cylindrical valve must face the heater hose when the heater lever is in the closed position.  As the lever is moved to the open position the inlet hole on the valve must come into alignment to open the connection and allow hot water into the heater core.  It can be installed such that a closed side faces the engine and has the valve is rotated it shows a another closed face.  Remember the valve only rotates 90 degrees from closed to open.

Jeff C.
1970 280SL 4-speed

[mbzse]

quote:Originally posted by DavidAPease

.../..  I'm not sure exactly when the access hole appeared../..

David and List,
The access hole for the heater valve was added to the 230SL in mid-June 1964,
chassis No 4550 (LH drive) and 4585 (RH drive)


/Hans in Stockholm

[DavidAPease]

Hi, Hans!

Thanks, you're a fountain of knowledge.  Now Greg will know whether he could have done the job more easily.

-David Pease
'66 French 230SL

[pcbenz]

Thanks Jeff,  I will take a look and see how well the valve is moving.  The cables move easily and there is heat produced but not enough to be comfortable. I also notice cold air coming in around the side vents when the lever is closed. I'm sure that is not helping the matter.

Thanks again for your reponse.
Phil

quote:Originally posted by Lax882@aol.com

PCBenz,

There is no fine tuning adjustment of the heater lever cables  behind the radio.  Maybe one of your cables has come loose and/or one of the air louvers is stuck.  Hard to say.  The heater core valve is accessable from the engine compartment via a firewall plug near the fuse panel.  Remove the plug and you should see the valve open and close (rotate 90 degrees) by using the heater lever.  If operating correctly I think the heater will work fine in 20 degree or lower temperatures.

Jeff C.
1970 280SL 4-speed

[pcbenz]

Thanks Rodd,
I recently changed coolant however, I didn't do an agressive flush. Perhaps the core is needing a good blast from the garden hose. Today I thought I smelled coolant while driving however, I saw nothing dripping or leaking on the floor. Makes me a little nervous though.

Phil  

quote:Originally posted by rwmastel

quote:Originally posted by pcbenz

.... never tried the heater until recently. I has poor performance in the 20 degree Kansas weather.

PCBenz,
I had little heat in my car when I purchased it.  Actually the engine ran too cool in the winter (60C/140F).  The next summer I back-flushed the coolant system, put in new MB coolant/water, and put in a new thermostat.  It's been great ever since.  That's my advice.

Rodd
Powell, Ohio, USA
1966 230SL, Euro, Auto, Leather, both  tops
1994 E420

[George Davis]

pcbenz,

my heater valve showed plenty of evidence of leakage, but nothing on the floor.  I'd say if you smell coolant, it's time to check it out.  It may just be a bad o-ring, and that's a pretty easy fix.

George Davis
'69 280 SL Euro manual

[jszeman1]

So..  am I to assume since I have an early 230SL with no access hole on the firewall that I cannot change the O ring for the valve unless I pull heater core?

[jacovdw]

That would be correct John...