Pagoda SL Group
W113 Pagoda SL Group => Body, interior, paint, chrome, and cosmetic items => Topic started by: dngalura on November 03, 2006, 23:08:11
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Gentlemen,
I have this overheating inside the cabin, I think it's coming under the dash. The heaters are closed, but it still get hot. Could it be that the flaps on the heater are not closing properly? How can I reduce this or eliminate it? Getting into the heater core is difficult. I was reading the forum and one of the discussions was on this issue and one suggestion was to install a T-bypass hose between the ingress and egress of the water system going into the heater box (Jeffc280sl ?)Does it work? Please elaborate or any suggestion. Thank you.
Dan G '70 280SL
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These cars have very little insulation between the engine and the cabin and the engine throws off a lot of heat. While you may have issues with the flaps or the heater core not closing fully (i.e. moving the bottom left lever all the way to the right), it is difficult to substantially reduce cabin heat. (edit-in the engine area on the firewall, there is a rubber plug about 2 inches in diameter. Remove the plug and see if your linkage that closes the heater core valve needs to be adjusted.)
I have added reflective foil backed insulation, added Dyna-mat and replaced my carpet and this seemed to help a lot with noise and heat. I provided extra insulation at the transmission tunnel-I have an automatic and the chrome plate at the gear shift still gets quite hot-this is the way these cars are.
Not sure I added much but it's probably nothing wrong with your car, it's pretty much the way these cars are.
1971 280sl Tunis Beige Metallic (restored & enhanced)
1971 280sl Tobacco Brown (low mileage stock)
1970 280sl Beach Driver with a touch of rust
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Thanks Tom, I'll look into that rubber plug. Never knew what it is for.
Dan
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Dear Tom,
I found the rounded rubber cover, and removed it and found that the lever is disconnected from the round metal gismo. What is this? I can see a square thing and in the center is a hole, looks like this is were the other rod is connected. The center screw is missing. Does this square thing moves? I try to moved it with a long nose plyer, it won't move.
I also moved the lower lever inside the car and it moves this rod.
How do you re-connect this rod to the round gismo. What kind of screw(metric) and size, only if you know.
I was also reading the forum and a discussion about this is there re: heater valve, on or off.
Anxious to hear from and the group. Thanks Dan
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Dan,
You need to read up on how the heater works. Search the forum for lots of good info. I will try to get you started:
The round gizmo with the square on the top is the heater core valve. This gizmo must turn in order to turn the hot water (heater) on and off. The square on the top attaches to an arm with a square hole in it, which in turn attaches to the dash heater lever linkage, to turn the valve. The hole is for a screw to hold the arm to the valve. If you look at the photo in Bob Possel's "Heat On/Off?" thread, you will see the arm screwed onto the valve.
Here is a write-up from George Davis that gives some details on removing and refurbishing this valve:
http://www.sl113.com/forums/index.php?topic=2514,heater,core,valve
If you cannot rotate or remove the valve, there is a very cool procedure that involves putting together an "extractor" tool; if you need it, I will find the description.
There is lots of info on this subject in the forum. If you need more direction, I'm sure we can point you to it. Good luck!
-David Pease
'66 French 230SL
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For what it's worth - my car does not get hot inside even in summer (other than from the true ambient temperature), as long as I have the heat off. On my car, a previous owner installed an extra manual on/off valve in the hose in the engine compartment right before it goes into the firewall to the heater box, because the original heater valve is frozen. I have not gotten to repairing it yet, also because the manual valve works so well. I just close it in the summer and open it in the winter. I will take a picture of the extra-added valve and post it here sometime in the near future.
Closing holes in the firewall (there are many as conduits for cables etc and sometimes rubber plugs are missing) will cut down noise considerably and, I guess, also some 'stray' heat. Then, there are the 2 aluminum plates in between the exhaust pipes and the car floor that, when not in place, will make a difference in the amount of heat entering the passenger cabin.
Cees ("Case") Klumper in Amsterdam
'69 white 280 SL automatic
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Thanks to Tom, David P, and Cees K,
I read all your comments and leading me to forums discussions, I now am ( I think) well equipped to tackle this issue. I hope the heater valve will be fixer friendly, with all the tricks and cautionary measures. I'll keep you posted.
thanks again.
Dan
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Hi Dan,
Read my updated post on the heater valve (Heater Valve - Heat On/Off). Overall an easy job, if you follow the advice of this site and be careful not to drop the valve into the core.
We all know that these cars get hot in the cabin... but I also noticed heat coming out of my vents during the summer months, making it all that much hotter inside the cabin.
As I replaced my heater valve o-ring I noticed that the old rubber ring was completely flat (squished). The new rubber o-ring is round and should provide a nice clean, tight fit against the valve side wall. I am hoping that the new valve o-ring will now stop and start the heat flow, as needed, and help the valve work more efficiently.
While working in this area, I also ended up replcing the rubber around my air flaps. The old rubber was worn out and some pieces missing. The new rubber will make a nice seal. Also replaced the rubber around the main, large air scoop vent plate. Now when I close off the outside air, it really stops the air from coming into the cabin.
Good Luck!
Bob
bpossel (Memphis, TN.)
'71 280SL / '97 E320
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quote:
From Cees:
For what it's worth - ..... On my car, a previous owner installed an extra manual on/off valve in the hose in the engine compartment right before it goes into the firewall to the heater box, because the original heater valve is frozen. I have not gotten to repairing it yet, also because the manual valve works so well. I just close it in the summer and open it in the winter.
Here's one I saw on a 107 fitted with a diesel engine [:(!]
Download Attachment: (http://images/icon_paperclip.gif) BurghHse086.JPG (http://www.sl113.org/forums/uploaded/naj/20061158411_BurghHse086.JPG)
42.31 KB
naj
68 280SL
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Hello Naj - yes, it's somewhat like that, although not quite as rudimentary (the one in the pic looks like a fire hydrant valve!). But that is how mine works as well and, again, it is very effective as long as you don't mind getting under the hood a few times a year to operate it.
Cees ("Case") Klumper in Amsterdam
'69 white 280 SL automatic
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Gentlemen,
For now, the simplest way ( I think ) was to connect a open/closed valve to the ingress hose to the heater core. I got one from the plumbing department at Home Depot and connected today and it works.
the weather here in Southern California is still warm, this makes riding more pleasant. I still plan to work on the heater valve when time permit.
Thank you all.
Dan
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I put some funky house insulation under my carpets - not over the tranny tunnel as it makes the carpet fit poorly.
Basically it reflects/absorbs some of the heat and makes the cabin far cooler
(an earlier version of this:http://www.tri-isosuper10.co.uk/)
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Dan, check under your car to see if the fragile aluminum heat shields are in place. Check the proximity of the pipes to the floors-might be too close.
Walter
1967 220SL-diesel
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There are usually 3 under dash panels?
I used silver lined 25-30mm thick foam to line them. This reduced lots of noise as well as summer heat.
These panels are available new.
Bob Smith (Brisbane,Australia)
RHD,1967 early 250 SL, auto
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has anyone used DYNAMAT to line the under dash panels? if so did it work well to reduce noise and heat?
quote:
Originally posted by hands_aus
There are usually 3 under dash panels?
I used silver lined 25-30mm thick foam to line them. This reduced lots of noise as well as summer heat.
These panels are available new.
Bob Smith (Brisbane,Australia)
RHD,1967 early 250 SL, auto
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I put the Dynamat every where I could stick it in my interior under the carpet. I put new pads under the carpets and lot of insulation also. There a many of the pads for the firewall. I think there are a couple in the engine compartment below the top pad that can only be replaced with the engine out. There are also more under the dash. The Dynamat does work very nice and I am happy with it.
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I used dynamat on my 220D. Inside the doors on the interior of the door skin and the outside of the interior door metal. I put it in my trunk lid and all interior metal trunk surfaces.
On the floor boards I used dynamat, a dense foam, factory carpet, and mats. It was probably 1.75" thick. Really quieted the car down. The floor boards seemed like they made the most difference.
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From Cees:
For what it's worth - ..... On my car, a previous owner installed an extra manual on/off valve in the hose in the engine compartment right before it goes into the firewall to the heater box, because the original heater valve is frozen. I have not gotten to repairing it yet, also because the manual valve works so well. I just close it in the summer and open it in the winter.
Here's one I saw on a 107 fitted with a diesel engine [:(!]
naj
68 280SL
Hi Naj
is this really as straight forward as just putting an inline valve in ?
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Paul,
I'm convinced my heater control valve leaks so that even in the off position hot water from the engine is cycled through the heater core and into the cabin. Some of us have installed a heater bypass hose on our cars. Utilizing a 3 way valve like the one in the picture below you can control the flow of hot engine water by routing it to the heater bypass hose and/or the heater core. You will need to buy a T fitting and a piece of heater hose also. Make sure you buy a T port type valve.
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You might want to try one of these, I have one in my heater bypass hose.
http://www.cbsonline.co.uk/heater-valve--15mm-58-htrv15-479-p.asp
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David,
That looks like a perfect valve to use in my current bypass setup. I have a similar stop valve but I can not control water going to the heater core. My original thinking was that the heater core valve would do that. But since I think my heater core valve is leaking I want to control the flow of water to it. Another member told me about 3 way valves so I have decided to go that way. The 3 valve will replace the T fitting for water coming from the head and the shut off valve that currently sits over the head cover. With a T port 3 way valve I will be able completely close off hot water going to the heater core and route it to the bypass hose. When open the valve will permit hot water to flow to the heater core and bypass hose.
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thanks for your answers. I have put one of 'David"s' taps inline on the pipe going into the heater and turned it off so that no water goes past the firewall. The idea being that when I need heat I simply turn it on. I haven't done the T thing as the engine is cool enough and hasn't blown up in the 25 miles I've done since.
So, at last, no more wafts of sickening heat at my feet.
It was that simple................
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Went ahead and installed a SS 3 way valve like Awolff280sl suggested so that I can shut off the flow of hot water to the heater core and direct it to the bypass hose. Here is a pic. I'll find out soon if it solves my cabin heating problem and advise.
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Wow, that is one ugly valve setup. Sorry, but I would rather be hot than open the hood and see that contraption. There must be a better way. Probably just fix the original valve.
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Kind of agree with graphic66....sorry but that looks ugly. I have a similar problem in my bmw 73 csi E9. In those cars the circulation of hot water into the heater core is continous...cant shut it off, no valve. You get the hot air by turning on the fan...but water still circulates no matter what. I thought of a valve like that...but just cant get myself to do it an mess up the looks of the engine compartment.
abe
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Wouldnt it be easier to just replace the heater valve o-ring and "fix" the on, off issue?
It's really not that difficult. I would be happy to answer any questions on this, as I am sure others would as well.
Bob :)
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I agree that fixing a leaky heater valve would be a better solution than an "ugly" by-pass, but this didn't work for me. I had the heater core on the bench when I replaced the valve, and I made sure that it was closing properly. But after all was said and done, I was still getting heat in the cabin. I'm unwilling to tolerate this if I want to drive the car in Florida during the summer, even though my A/C works well. So, I went about trying to find the causes of heat in the cabin.
1. The heater core still warms up even with a well-functioning valve: I've come to the conclusion that this is because the heater core will conduct heat from hot coolant sitting at the closed copper heat valve, (as well as at the heater core output, but to a lesser extent). An effective by-pass will eliminate this, at least at the intake pipe.
2. The firewall: I put Dynamat under a new firewall pad on the engine side. In the cabin, I put a layer of Dynamat covered by a layer of insulation material that I found locally. This material is like miniature bubble wrap sandwiched between foil.
3. Tranny tunnel: Used Dynamat plus the bubble wrap stuff
4. Exhaust pipes: Thermo-tec wrap (thanks Jim), heat shields (stock), and Dynamat plus the bubble wrap material in the cabin on the passenger side.
3. Differential heat: I could feel heat coming from my diff if I removed the parcel shelves after a good drive. Used Dynamat plus the bubble wrap.
4. Less than perfect sealing of closed cowl vent and side cabin vents: At high speeds I was able to improve but not completely eliminate air flow thrrough the cowl vent and side cabin vents using weather stripping. I still need need to close the chrome louvres and swivel flaps to eliminate all air flow at higher speeds.
5. Finding air leaks in firewall (used a light in the engine compartment in a dark garage, thanks Cees) and plugging them with 3M weatherstripping putty.
6. Window "tinting": I selected a material that reduces heat without significantly darkening the windows.
I can say that I have solved my heat in the cabin problem with all these measures.
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If the heater valve is like the 190SL, there is always a small amount of coolant passing through by design. That's what the small slit is for off of the hole. I haven't had the 113 valve out to know if it's different.
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To each his own.
The original concept of the bypass hose was to try and reduce engine temperatures. Many of us have turned the heater valve to full open when engine temperatures rise while sitting in traffic on a hot day. I've also turned on the fan to move more air through the heater core to reduce engine temps. So I decided to try a bypass hose. I began with just 2 tees and the bypass hose going over the head. Engine temps are much lower and I now have no fear of a head gasket failure or other problems associated with over heating the engine. It worked so well I decided to leave it in place.
A secondary problem was heat in the cabin with the heater valve in the off position. The heater core valve is indeed like the picture in the prior post. I thought the top groove was for an o-ring to seal the valve so that it would not leak out the top of the heater core tube. I think mine also has a less pronounced groove in the bottom. I thought maybe that also was for an o-ring but it doesn't appear deep enough and I was unable to get an o ring to stay in place. This maybe the source for hot water entering the heater core when the valve is in the off position. In any event I have tried to fix it. For whatever reason my valve leaks and I have considerable hot air on my feet coming from the ducting when the valve is in the off position. In the cooler months it doesn't seem too bad. In the summer its very annoying.
The heater core bypass hose is already in place and Andy has a solution for my secondary problem. The valve is a little ugly but it works great. Someday when I have nothing else to do I may install a more modern valve from another automobile and install a hard pipe to carry water behind the head for the bypass. That would be nice but right now I'm enjoying a cooler cabin and engine.
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The top groove is for the O ring. It's just not on in the picture.
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Thanks John.
I had to blow up your picture to see the slot your speaking about. I don't recall having a similar slot on my valve.
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Here is a pic of our heater valve. This is a pic of mine. The long screw and string is only used to help install the valve without it falling in the heater core. There is also some plumbers lube to keep the valve movement very easy...
The W113 valves do not have the slit like the 190sl.
Bob
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I may be one of the lucky ones but I have never experienced excessive heat in the cabin (especially in the winter ;) ). Oh sure, I have been out on very warm days, and with the top up, it can get stuffy and warm (no A/C), but this is more an external thing than an internal one. In fact, others have talked about the shifter and its box sizzling -- never felt that either... I guess my heater valve must work ok -- and I have some dynamat-like stuff down but that's about it. For best ventilation, of course, I keep the top down.
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Its 92 today so a perfect day to check for cabin heat sources. Now that I have the heater core shut off valve installed I can definitly say my cabin heating situation was caused by a leaky heater core valve. The pic Bob posted looks like my valve. If you look closely you can see a shallow groove at the bottom of the cylinder. The tolerance of my valve and the heater core tube must be such that I have blow by and some amount of hot water always circulating through the core. It has been suggested that MB designed the valve so there was always some hot water moving through the core. If true this may have been an effort to reduce engine temps by relieving the head of some build up pressure of hot water. Prior to installing the shut off valve I had heat at the gas pedal area coming from the heater ducting with the cowl vent open and the heater core valve in the closed position. Now there is only cooler outside air coming from the cowl vent at my gas pedal foot. It's ugly but I'm pleased with the mod and thank AWolff280SL for the idea. No other cabin heating issues. I have the original firewall pad and both exhaust heat shields are in place. I also have dynamat and heavy padding under the carpet.