problems

[peterm]

Is there no solution for some common problems?  I think all of these cars have their own personality, sometimes I think my car in auto menopause!

I have been to several shops in an attempt to solve the cooling issue that cropped back up this weekend.  I wouldn't even think of turning on the ac when its over 70 degrees out.  All the usual supects, thanks mostly to this forum, have been addressed, I'll just sweat, and avoid traffic.

Electrical issue,  somewhere there's a drain no-one can find, permanent trickle charge it is!

Wiper stalk switch is extremely fragile and often the wipers will go on, unfortunately when I turn them off they are at 45 degree angle no matter what I do! Quick fix at the next light is to stand up and lean over the windscreen and push them back.

Arrrrgh!  If this damm car didn't look so good a porsche 993 widebody could be my next classic!!!

Sorry for the rant

Peter

[TR]

Peter -- I know that feeling only too well, and share your frustration.  I did everything over a number of years, yet the engine would still over-heat...just like you've said, even at 70 degrees.  In my book this is simply not acceptable.  We did everything, and ultimately even put in a brand new engine from Metric...Yet still had that #@&*(!) overheating problem.  Then my lead mechanic talked with Gernold.  Gernold suggested a M-B developed re-circ. kit, which the local M-B service dept. would never have found.  Gernold also had us pull the throttle-body and send it to him for modification.  BTW, if I ask for a consultation with my lawyer or phsician then I expect to pay for their valuable time and expertise...personally, I see our W113 gurus in that same light.  We're lucky, really lucky, to have them.

My car is still at the interior shop, so haven't yet had a chance to try out the latest engine cooling mods.  But after owning this car for 20 years I'm actually hopeful the engine will hold temperature under any conditions, just as a new car will.  We shall soon see.  I expect the old 280SL to perform just as well as my '04 CLK500 cabriolet in this sense.  I know this sound ridiculous to some people, but I'm dead serious about it.

You've described a problem that almost caused me to dump my '71 280SL of two decades.  I just would not except what I thought were lame excuses like, "these cars were never meant for hot weather, or these cars were never intended for A/C".  IMHO it's just a matter of physics, and it is not too much to expect a '71 280SL to hold engine temp when the car sits at idle, with the A/C blowing ice cubes, and the weather is 70 degrees...or 115 for that matter.  (I'll get this done, or go broke trying).

Sorry for the rant about engine over-heating and air conditioning, but this subject gets me going.  Peter, you are welcome to contact me off-line about this if you wish.

What year and configuration is your W113?

Tom in Boise
'71 280SL 4-sp, signal red, lt. tan interior, restored/enhanced

[rwmastel]

Peter,

Engine cooling issues:  As you noted, there are many posts on this topic.  I would continue to search using various key words hoping to find a critical posting that you have not found yet.  If you let us know the details of what has been done to your car for this issue, I'm sure the members will provide more options.

Electrical drain:  I'm no electrician, but there must be a way to divide and conquer this problem.  Anyone?

Fragile wiper stalk:  I know there were posts between several people interested in rebuilding the internal switch to this stalk.  That is, the switch inside the steering column.  Have you found those posts?  Is that where the problem is, or is it in the switch at the end of the stalk?  Replacements are available ($$$$$).

Wipers stopping at 45 degree angle:  I'm suprised you can just "push them back down".  I thought they were attached to a threaded post.  I suggest you remove them and examine their attachment position.  It might be stripped and that's why they don't stop in a normal spot, because they've spun on the post.

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

[peterm]

My car is a 71 280 sl.  

Cooling- recored radiator, replaced water pump, checked timing, replaced fan clutch, has shroud, water weter, several people have posted addition of electrical fans but I can't get my local mercedes gurus to bite.  I am beginning to believe I have the perfect late spring early fall car.

Electrical problem,  when I purchased (2 years ago) I should have looked more carefully at the scuffed battery terminals seems it must have been jumped alot.  I now know why.  Simple sears trickle charger keeps me from going dead when idle more than a week.  I have been unable to locate a auto neurologist so this ill live with.

Wiper stalk I beleve there is a fracture in the switch  beaucoup bucks to replace, not worth it, just caution with signaling.  Yes they easily return to position when nudged.  They have full range of motion and just don't want to stop where they should.  

I'm thinking flatbed to gernold or benz dr, or i can just live with it.

[TR]

Peter -- Ah ha ... another overheating '71 SL with A/C!  I did everything you've mentioned, and much more.  My guess is you ought to get that special re-circ kit installed and the throttle body mod done.

I'm no mechanic, but based on a lot of painful experience when it comes to a '71 overheating, those are not tough or particularly expensive things to have done.

Tom in Boise

P.S.  Purists may not approve of some of the mods we've made, but we've added dual electric fans (15"?) on the back side of the radiator...a small elect. fan. (10"?) just behind the star of the grill (note: very, very difficult to fit these).  Programmable timer to keep the fans running and coolant circulating after hot engine shut-down, etc.   Also added a large special re-circ line (2", ~8 ft. long) w/ a big new elect. aux. pump, etc., etc.  The old FrigiKing A/C unit looks original, but we've also added new style compressor, condensor, high-volume fan, addt'l hidden ducting.

In another month or so I'll be able to report how this all works...or doesn't work...but I'm pretty optimistic.  [Note: seat heaters, seat active ventilation (built-in fans), and built-in seat massagers are in the process of being installed now...using OEM parts that are now optional on new M-B].

[graphic66]

As for the electrical leak you might be able to find the cirquit involved by pulling a battery connection and then touching it to the battery post and looking for a small spark, be careful to ventilate the area good and wear safety glasses and face shield in the unlikely event the spark ignites hydrogen fumes from the battery. If you have a small spark then, one at a time pull a fuse and see if the spark is still there. If it stops when you pull a fuse you have isolated the cirquit and you can then start unhooking each draw on that cirquit one at a time and you may isolate your problem. The wipers could be the 10mm nut holding the wipir transnission frame to the wiper motor accessed from the passenger footwell area inside the car on the shaft of the wiper motor. If they are out of time just loosen the nut and with the wiper motor parked place the wipers in the parked position and tighten the nut, a good cleaning of the mating parts and some loctite can help hold them in place if you have worn the mating parts smooth. As for the overheating maybee check the engine timing as this could affect running temps. Redline Water Wetter may also help, but now I have heard these additives simply push the heat from your coolant to your oil and the heat is still in the engine only undetectable by you water temp gauge. That turn signal wiper stalk can be dissasembled on the bench but is not for the small tiny part impatient challenged individual, but once conquered can be quite satisfying. I bought a broken one to practice on and now it works great and I will rebuild the one out of my car for a spare.

[George Davis]

Peter et al.,

you said recored radiator, but did you install a high-efficiency core or the stock type?  If stock replacement, bite the bullet and have a high-efficiency core installed.  More tubes, higher fin count, louvered fins.  I installed AC (aftermarket, with rotary compressor) and got a high efficiency core at the same time.  On hot days with AC on the temp is higher than normal, but not by a lot.

The fan should be as close to the radiator as possible.  There is a book spec, I think it's 10 mm at the rad top flange, but am not certain.  Closer is better, as long as the fan doesn't hit.

If you have the original York compressor, consider replacing it with a newer type that puts less load on the engine.

As something of a quick band-aid in stop and go traffic, put the car in neutral and raise the revs to about 1000.  This pulls more air through and when my car got real hot (prior to installing the AC and high efficiency core) this brought the temp down very quickly.

Good luck!



George Davis
'69 280 SL Euro manual

[A Dalton]

<As for the electrical leak you might be able to find the cirquit involved by pulling a battery connection and then touching it to the battery post and looking for a small spark, be careful to ventilate the area good and wear safety glasses and face shield in the unlikely event the spark ignites hydrogen fumes from the battery. >

 That works in a pinch, but an amp meter in series with the ground terminal at the bat will give you the info and the actual draw.  Because it does it standing , it more likely is a circuit before ignition switch...

[Malc]

Agree with Mr Dalton, use an ampmeter on the battery. removing fuses one at a time helps to isolate the problem if it's on a protected circuit. If you still have it after all the fuses are out then it's most likely on your starting/charging circuit somewhere.
good luck
Malc
ps This is what "old" cars are for... to drive you nuts[:p]

[waltklatt]

Peter,
Sounds like your wiper mechanism relay that is housed inside the wiper motor assembly is dirty.  You will need to remove the entire wiper motor and open up the relay box to clean the contacts.
There is nothing wrong with your signal stalk.
Hope this helps.
Walter Klatt
1963, 1967 230SL's.


Wiper stalk switch is extremely fragile and often the wipers will go on, unfortunately when I turn them off they are at 45 degree angle no matter what I do! Quick fix at the next light is to stand up and lean over the windscreen and push them back.

[farmerford]

peterm:

My 1971 280SL automatic transmission with Frigiking AC overheated just like yours.  In fact, the previous owner got it so hot that #4 cylinder scored and now pumps enough oil to foul the plug every 2000 miles or so.

First, I reduced the anti-freeze concentration to 20% (just enough to lube the water pump, prevent rust, and protect from a sudden light freeze), added Water Wetter, and put a 13" electric fan behind the grill.  All this helped, but it did not solve the problem.  After experimentation with an amateur "wind tunnel" I determined that air flow is not a major part of the problem.  But water flow is.  At relatively low engine rpm the water doessn't move very well from the rear of the cylinder head back to the radiator. Indeed, there was apparently a change in the water passages in later 280SL cylinder heads to help the problem, but it didn't do much.  I have one of the last ones made (early 1971).

I heard about the MD recirculation kit and found one on line (I can't remember where) for about $400.  I decided that was too much, so four years ago I made my own.  I don't know exactly how the MB rig works, but mine has a 1/4" bypass hose which carries coolant from an existing fitting at the rear of the cylinder head into the upper radiator return hose.  Not the prettiest rig, but it works. It is amazing how that little amount of water moving from the back of the cylinder head directly into the radiator (rather than flowing forward through the cylinder head and then through the thermostat) could make such a difference, but it does.  Indeed, in the winter I have to block off the recirculation or the car will never warm up!

So, the recirculation rig solved the problem.  I am not sure whether the recirculation rig would have solved it alone, but the reduced anti-freeze and Water Wetter are easy to do and the electric fan wasn't much of a problem the way I made brackets for it.

I plan to have Metric rebuild my engine this year and I will also install a high efficiency radiator at that time, but it is not really needed.

E-mail me for more details if you want them.

Charles H. Ford, Jr.

[Malc]

Charles,
To get the water to move from the back of the head do you use a pump?
Have you put a T piece in the top radiator hose or did you splice into the "header" tank for the radiator hose?
Cheers
Malc

[farmerford]

Malc:  I did not use a pump.  I will look at my rig more carefully when I get home tonight and send you a more complete description tomorrow.  Also, if you have warm weather problems like overheating, you may also have hot-start problems due to gasoline vaporization.  I had them and solved them with a modification to the cold-start-valve.  Let me know if you are interested.

Chuck Ford

Charles H. Ford, Jr.

[farmerford]

TR:

Could you describe in more detail the new "recirculation line 2" ~8' long"?  Is it in the radiator circuit or AC circuit?  How is it hooked up, etc.?

Thanks.

Chuck Ford

Charles H. Ford, Jr.

[A Dalton]

<<you may also have hot-start problems due to gasoline vaporization. I had them and solved them with a modification to the cold-start-valve. Let me know if you are interested.
>>

 What mod would that be ?
Tnx

[TR]

quote:Originally posted by farmerford

TR:

Could you describe in more detail the new "recirculation line 2" ~8' long"?  Is it in the radiator circuit or AC circuit?  How is it hooked up, etc.?

Thanks.

Chuck Ford

Charles H. Ford, Jr.

Hi Chuck -- Isn't it interesting that it's '71 280SLs were talking about here in terms of overheating?  There are a few other W113s in the Boise area (not many) ... and my local M-B dealership has done a good job for me of measuring every one (all older than mine) that comes in with an IR temp. gun.  For reasons I really don't understand mine always had the largest temp. differential from the front to the back of the head.  And this is even after a brand new engine from Metric.  I haven't had a chance to try all the new cooling mods out yet, but think the car will now be able to hold temperature during long periods of idle with the A/C running on even the hottest of days...And it gets hot in Idaho, up to 110F, on occassion.

As discussed, my mechanics have done everything mentioned in this and other threads, and then some.  That stuff helped, but did not cure the problem.  My hunch, although not yet thoroughly tested, is the 2 most important things will have been adding that special M-B recirc tubing system Gernold recommended, plus the small throttle body modification he's made.

I pushed my mechanics to go the extra mile.  And that is the large volume recirc. piping arrangement mentioned.  As I'm not into doing any of this work myself I'll doubtlessly get this description wrong.  But here's the rough idea: A new electric pump (with on/off & volume controls) was placed right after the outlet side of the radiator...driver's side, bottom.  This new, big pump helps the normal (new) M-B water pump.  A specially fabricated combo of pipe & hose takes the coolant down the driver's side, crosses over near the transmission, comes back up the passenger side, and then with a newly fabricated "y" piping arrangement plumbs back into the coolant inlet of the radiator.  When you go down the driver's side, then across to the passenger side, and back up the passenger side it becomes quite a distance...and it adds a lot of volume for extra coolant.  

With this attempted description I am doing no justice to the work of multiple people to design, fabricate, install, and setup this arrangement.  I think it would be much better if I take a few digital photos and send them to you.  As the car is still in the interior shop it will be several weeks before I can get under it to do this.

To give you just a small feel of the trouble we've gone to in order to make this '71 280SL run cool, the lead M-B mechanic went through four (4!) brand new water pumps...he even took them all apart, made clay impressions between impellers and bodies in an effort to select the best performing pump (there was a surprising degree of variability in these brand new pumps from M-B).  I freely admit that no sane person would go thru all this effort.  As friends & family point out this is obsessive.  But I don't care, because when we're done I suspect this may be the only '71 that will told engine temp like a new M-B will during prolonged periods of idle, with A/C running full blast, on the hottest of days.

As you can tell, I'm umimpressed with the responses that one sometimes hears, like "these cars were never intended for hot weather", or "these cars were never intended to run an air conditioner", or whatever.  My simplistic view is, hey, it's just a matter of physics!  And my guidance to the mechanical team is, "let's get 'er done"!

More than you asked for I know.  But I see no reason why these beautiful cars shouldn't be used during the time of year we may want to use them the most...IE, summer.  Probably, I should send a photo of the new control switches that are being hidden/mounted inside the ashtray for the internal seat fans, the seat heaters, and the seat massagers too...har!

Tom in Boise
'71 280SL 4-spd, signal red w/lt. tan interior, restored/enhanced

[TheEngineer]

My car has a three row radiator and Frigiking AC. It does not overheat and the temperature at the AC outlet is 42º. I did replace the Freon 12 with Duracool. Pulled a vacuum of 100 mbar and let it sit over night to get all the moisture out. In the summer I set the idle up a little, in the winter I turn it down to about 650 RPM. I have the York compressor. I had the radiator rebuilt. The AC does not reach the low temperature when idling: There is insufficient mass flow.

'69 280SL,Signal Red,007537,tired engineer, West-Seattle, WA

[norton]

Some info on this site about cooling that might help http://pages.prodigy.net/jforgione/MB_S500.html

Mike Halleck
Chesterfield Mi
71 280SL
68 250SL (parts car)
94 E320 Coupe