driving temperatures

[starparts]

I am a long time Mercedes collector, have some Coupes and bought recently a 230SL 1966 with a 280SL engine.
Besides all kind of little problem I noticed that the engine runs much warmer than the 280SE Coupes. The temperature is mostly around the 90 degrees C or higher with acceleration, up hill and/or ambient temps in the twenties.
My question is if this is normal for the SL's ?
Cees den Holder

[gatorjaws]

My 230sl was running around 195 f so I had the radiator gone thru & put in a new pump with no change. I installed two electric fans(one push & one pull) that pretty much cover the whole radiator front and back & I installed a 165 f thermostat. The car runs most of the year @165 but in mid summer it still climbs to 195.Also, the fuel injection pump does not like the lower temp so I am going back to one fan & a 195 f thermostat. I too would like to know what is normal for these cars because I was thinking about having a larger radiator built now that I have room beacuse no fan on the pump.Since I was not using the fan on the pump I went with a short pump for more clearance. I drive my car alot & so I am more interested in performance than original. 

[Jonny B]

I had a number of issues with warm running, and finally decided to have the radiator recored to three rows of tubes. I also went with the lower temp thermostat, and voila! Cool running. I can see a small bit of a rise if on a long grade in hot weather, but not really much.

[Jordan]

Cees,  the manual says the temp should run around 80 degrees C.  Mine runs just a bit over 80 when highway driving.

[Richard Madison]

Cees:

My 1969 Euro version runs at about 80c unless I'm in a stop and go situation on a hot day when it might go to 90 or a bit more.

Richard M, NYC

[starparts]

Thank you all for the information. It shows that the same car, same engine, behaves differentl. I also cleaned first , then recored the rad, changed thermostate and put 80C in, checked waterpump, changed visco fan unit and changed all hoses. Visco fan makes a difference when you are driving, you can see on the gauge when it kicks in, but for the rest the engine sticks close 195F or 80C. It feels warm and I am not comfortable because it is too close to
overheating. The MB workshopmanual for the 130.980 engines allows operating temp between 75 and 95C. If I am pushing the revs or go up the mountain I am at 95C quickly, but it does not go to overheating or 115C( in the pressurized system).
I feel that the rad enlargement could be a good solution. Why I am uncomfortable  with the situation is because my Coupe with the same 280se 130.980
engine is solid 80C plus maybe 4-5 degrees if I do similar rev pushing or ralley up the mountain.
Cees

[starparts]

Sorry , I made a typo in the beginning of the previous reply. The temp of the engine sticks at 195F or 90C ( I typed 80C)
Cees

[Cees Klumper]

Hi Cees - my 280 SL now stays very steadily on a very healthy temp (can't tell from memory) and basically never overheats, not even in stop and go traffic iin warm weather. It was not like that when I first got it though, before the engine was rebuilt.

I have two more possibilities for you: (1) could there be air trapped in the system somewhere and (2) are you sure your gauge is accurate. May want to check with one of those infrared temperature measure thingies?

Good luck, overheating is very bad for the engine/cylinder head,
Cees

[SteveK]

I also have a 230 with an early 70's 280 engine.  I did the 3 row radiator and then the Mercedes Bypass which both helped.  What made the biggest difference however was the 9 blade fan.  I can not sit at a traffic light in 95 degree weather without the gauge lifting off the thermostat temp.

[harleydan]

Hi Steve K,

Where did you get the 9 blade fan?  Did you have to do any modifications or was it a direct bolt on?

Thanks,
Danny
1970 280SL silver Euro 4 speed

[starparts]

After having collected Benzes for over 40 years, I never experienced an active positive forum as in this SL Group. 
Cees Klumper:Yes, I filled the system properly, so the chance of having trapped air is minimum. Re temp gauge, I had the feeling it was correct, but to be on the safe side, I will check with infrared.
Steve K: I am checking around what is involved with a 3row rad. This makes sense. What is a Mercedes Bypass?and I do not know about a 9 blade fan available. I have now the six blade fan with visco.
Cees

[Amanda]

Ours ('66 230sl) also tends to overheat if we're in stop and go traffic, but then cools down as soon as we're able to pick up any speed.  As a result, we've been thinking installing a fan, but it sounds like that may only help if the car is moving anyway?  What is involved with having a radiator recored, and do I understand correct that is a change made to the existing radiator currently in the car? 

Many thanks 

[mdsalemi]

Just an FYI for those that have not taken a close look or investigated.

The "temperature indicator" on the Pagoda is not a gauge per se; it is a thermometer, with a bulb and capillary tube.  It reads regardless of whether or not the car is on or running--no power required.  I.e. there is no electrical sensor, it is purely an analog mechanical device.

Care must be taken when removing and re installing to prevent damage to the tube.

[66andBlue]

...  What is involved with having a radiator recored, and do I understand correct that is a change made to the existing radiator currently in the car?  ....

Amanda,
that is correct. You can take your old radiator to a shop that still works on these ancient devices (which may be difficult) or you can send your old one (core) to Gernold and he'll send you a 3-row hi-ef in return. See: http://www.sltechw113.com/parts.html

[Amanda]

Amanda,
that is correct. You can take your old radiator to a shop that still works on these ancient devices (which may be difficult) or you can send your old one (core) to Gernold and he'll send you a 3-row hi-ef in return. See: http://www.sltechw113.com/parts.html

Thank you so much, that is really helpful.  The overheating issue has been the only drawback to the car, so stressful to watch that guage climb when you get caught in unexpected traffic.

[starparts]

After all the advices and experiences, and considering everything I already checked and changed, I strongly believe that the solution for this borderline hot running is the enlarging of the amount of cooling water, in other words a bigger radiator. I have an appointment with a recommended shop.
The question remains : why does it happen in one car, and not in the other?
I think that the cars struggling with high temperature have maybe obstructions in the casting galleries of the block. Can be hardened sand, cast iron material,
rough casting etc. If we combine this with the fact that the amount of water in the SL cooling circuit is critical for the engine, the chance that temperatures quicker rise is big. All this in compare with the 280SE engine in the 108,109 or 111 bodies with big radiators.
Cees

[Garry]

I suspect it has to do with the amount of scale and junk that has built up in the block and the radiator.  Not much good replacing the radiator if you don't clean out the block as well.

I had mine re-cored to original spec and the block chemically flushed and now drive in 100+ degree heat regularly in summer here and have never had any high temperatures with it sitting around 80-85.

[J. Huber]

I look at it this way: there are a number of things that afflict our 113s over time (generally speaking)... of course, the list is never ending but these are the ones I recognize instantly as endemic to the Pagoda...

overheating issues
cold start problems
warm start problems sometimes
rust issues in the floors
soft-top scrapes and tears
worn suspension
broken heater levers/heater recore
noisy tachometer
worn out visors

Each and every one of these can be cured -- and avoided well into the future with basic maintenance. Most of our cars went through a neglect or Dark Age period but obviously are now experiencing a Renaissance -- one car at a time. So the trick is just to get through each of these issues and get the car back to normal.

My experience is a Hi-efficiency re-core and a thorough once over of the cooling system will lead to years of steady temperature -- as long as things are maintained.

All the things on my list can be done once and the car will respond as it should...

[SteveK]

The 3 row radiator was just a case of bringing it to a radiator shop in Houston and asking for it to happen. $425 later I had a rebuilt radiator which looked brand new.

The Mercedes Bypass was a modification MB made around 1971 to help with the overheating issues on the new 280 engines.  I bought it from the Classic Center.  I also took pictures of it and it's in the Technical Manual.

I found the 9 blade fan on e-bay.  It's plastic and was a direct bolt on (4 bolt not 3) 

If I was starting from scratch to solve a hot running issue, I'd do the 9 blade first, the radiator second and the bypass third.

[starparts]

Hi SteveK,
I found a 9 blade fan with a 4 bolt on system. I had it in my parts piles, but do not remember how and from where I got it. Mine has to be bolted on with a Visco unit. I will check the Bypass system.
Cees

[glenn]

Do any of your engines have an oil cooler? 

[starparts]

Glenn,
Yes, I have an oil cooler in the 230SL with 280SL engine
Cees

[SteveK]

I also have a oil cooler that I added.  Who ever did the conversion on my car installed the 280 engine without an oil cooler using the 230 filter housing.  I found a 280 filter housing on the web and then added an "Earls" oil cooler under the radiator, behind the license plate.  I'm really not sure how much it does, but it makes me feel better!

[Dick M]

I installed a heater by pass hose which pretty much solved my 280SL overheating problem

[holden66]

I also have a SL230 with a 280 engine.  I bought the car 3 years ago, and the former owner had just had the 280 engine put in.  I have not been able to gather any information on the history of the 280 engine put in, but the local mechanic that put it in said the engine was in very good shape.  In regards to temperature, mine seems to run about 180 (maybe slightly above) when in motion. When idling, the temp can rise above the 180 mark.  The engine seems to put a lot of heat back into the interior of the car, but not so much that it is uncomfortable.  I noticed that my fan is a 4 blade fan.  Upon reading the comments to your problem, I am interested in putting a fan with more blades on, and maybe beefing up the radiator.  I enjoy the power and pep of the 280 engine, but I have wondered if some other parts of the engine are somehow compromised somehow in order to make the 280 engine fit.  I am not a mechanic. 

Hope this helps.

Holden66