oil cooler

[n/a]

Hello
 I am having the typical heating problems with my 230 sl and i have tried all of the standared tactics such as new radiator w/high efficiant core, water pump, etc.. I have all but decided that this car will never cool properly as is. i just can't move enough air across the radiator at a stand still. In motion I have no heating problems what so ever.
i am intersted in installing an oil cooler on my 230 sl and i am not sure how to attach it to the engine is their an oil line that i can install this in or do i need an adapter for the oil filter?
i have also wonderd if the fan shroud from a 280 will fit?
any help would really be cool!!
thanks in advance.


Jerry P.

[George Davis]

Jerry,

just my opinions:
An oil cooler is a good thing, but will not help with your problem - in fact, if you use a 250 SL type oil/water cooler, the cooler will add more to the heat load.
A 250 SL type oil cooler can be added, I think Naj did exactly that, but it requires the entire filter head assembly as well as the cooler and lines.  With a 250 SL filter head, you could probably also add an aftermarket air/oil cooler.
I think the 230 and 280 radiators have different dimensions, so fitting a 280 SL fan shroud is iffy... but a shroud is still a good idea.
Moving the fan as close to the radiator as possible should help.
Adding an electric fan with either manual or thermostatic control is probably the most effective way to cool at idle.

Good luck with it... I am contemplating adding A/C to my 280 SL, so I too may soon be enjoying the fun of overheating!

George Davis
'69 280 SL Euro manual

[Cees Klumper]

Many have reported good results using "water wetter", a product which AFAIK enhances the cooling properties of the water in the system.

[Naj ✝︎]

Jerry,
If you want to fit the 250sl oil cooler let me now and I can give you details.
If you have a plastic fan, moving the rad closer to the fan is a 'no-no'
When I bought my 230sl, it had a recored rad and the gap between fan/rad looked adequate. However, in summer traffic one day, the engine got really warm and the outer extremes of the fan blades actually got sucked into the rad core. Another recore was required!
naj

naj
'Kloines Scheisserle'
65 230SL
68 280SL

[n/a]

Jerry,
I have concluded that our cars were not meant for both Houston summer weather and Houston traffic.
Mike Hanie has installed an electric cooling fan (actually 2 of them) in his Panamericana car. A month ago it was sitting at Helmut's, but I don't know if it is still there. If I had the room behind the rad (280SL), I would install electric fans. Mike says they work very well and several other have the same opinion, so it sounds like they are the best fix, if they will fit.
I have been through the entire cooling system, except the fan clutch and I am still not satisfied with the cooling. I have a new clutch and in the next couple of weeks I plan to install it.
Call me if you want and I can tell you everything that I have been through.

Regards,
Stan

[peterm]

HMMM am I to accept driving in the summer with the heat on?  I have a 71 280 with temp gauge easily hitting redline if stopped on an 85+ degree day.  With the AC on it soars to scary above red line region.  I was assuming that I need to go thru fan clutch/thermostat/ radiator recore response, I'm getting the impression that this investment may not help??

[Albert-230SL]

quote:Originally posted by jpyles

Hello
 I am having the typical heating problems with my 230 sl and i have tried all of the standared tactics such as new radiator w/high efficiant core, water pump, etc.. I have all but decided that this car will never cool properly as is. i just can't move enough air across the radiator at a stand still. In motion I have no heating problems what so ever...

Jerry P.

Hi Jerry,

Could you please give more details about your "typical" heating problems?: External temperature, gauge readings in motion and at idle... how many time at idle is necessary to overheat...

I also have a 230 SL (original fixed metallic fan, original but cleaned radiator, new standard thermostat) and it usually works at 80-82 ºC (176-180 ºF).
During 90+ degree day, and after long idle periods, it could go up close to the next non numbered mark (I guess 100 ºC / 212 ºF), but never close to the red line region, and it quickly goes down to 80-82 degrees as soon as I drive it. Driving during those days it also works at 80-82 ºC, and only go up to around 85-90 ºC (185-194 ºF) if I drive it hard on climbs. After talking about this with other Pagoda owners, I think this is the usual temp. range for these cars, so if it has a very different behavior... something is wrong (maybe the gauge itself?)

For this reason I don't think that heating problems are "typical" in the design of the W113. Mercedes cars are made in a generally cold country, but they test the cars under very hard conditions (cold and hot) before to launch them.
For instance: Böhringer's racing 230 SL (winner of the '63 Spa-Sofia-Liège marathon rally, recognized as the world's most demanding rally) only received an air/oil cooler, the water radiator was original... and the race was in August!

If there is any factor that causes overheating other than radiator, thermostat or water pump (wrong ignition, wrong spark plugs, water leaks, lean mixture, air in the cooling system, dirty cooling system, gasket...), the additional electric fan will help, but the problem will remain there.
Another trick (for cars with fixed fans) is to slightly increase the revs during the stops. In that way the fan turns faster, moves more air, and cools better.
I read somewhere that high grade engine oil (like 20W60) also helps.

Regards,


Albert de la Torre Chavalera
Barcelona (Catalunya/Spain)
Feb.'64 230 SL Euro 113042-10-002432

[n/a]

as to what my cars heating condition is like.

my car currently runs at the 80° to 85°C range during any driving condition that invloves moving the car in a forward direction. (10mph or faster.)
if the car is set at an idle it will slowly creep up to the red mark. maby 6-10 min. or in hevy trafic that prevents any speed obove 10mph. In the city that i live in you cant drive anywhare without getting stuck in traffic.
i have replaced the radiator, checked the water pump and thermostat. i have made sure that the radiator is as close to the fan as possable. i run a mixture of water,water pump lube and water weter. i have checked the ignition timing. i have adjusted the idle mixture. i have also ensured that my spark plugs are of the correct heat range. my oil pressure is great at all speeds . i have instaled A/C and it has the same behavior as before if the ac is on or off.  it dose heat faster wiht the a/c on and runs maby 5° higer during motion.
It makes  no differance what rpm i hold the motor at during stand still.
it still heats the same. I have also performed comprssion checks and leak down tests all with excellent results.
please help i am running out of ideas.
i have read that some have instaled electric fans with good luck. i am willing to try this but i would reather leave the factory fan if possable.

Jerry P.

[rwmastel]

Jerry,

Hi.  My 230SL's temp is fine when operating, but climbs to 100 when at idle on a hot day.  It's common, but I don't think it should do that.  In a strange twist, mine also used to not heat up to normal operating temp on cold winter days.  I flushed the system, replaced the hoses, replaced the thermostat, and put in new water & MB coolant.  This fixed the winter time cool running, but not the hot running at idle.  I have some observations regarding your issue...

Regarding your list of what you did:
- How did you test the water pump?  Is ther some way to measure flow rate in gallons/minute?
- At what temp is your thermostat supposed to open?
- You say that you "run a mixture of water,water pump lube, and water weter".  Does this meen no coolant/antifreeze?

Comparing Albert's list to yours:
- Are you sure you don't have air in the cooling system?
- Are you sure your cooling system is not clogged?  Have you tried to flush it?
- Are you sure your head gasket is good?

Just some questions.  I would hate to see the symptom solved instead of the problem.

Rodd
1966 230SL Euro
1994 E420

[n/a]

My theory is that the Mercedes engineers probably knew what they were doing, so adding new technology may hide the problem rather than fix it.

On my 280sl, which has a factory oil cooler and a recently re-cored radiator, I did two things (after checking the water pump, belts, thermostat and fluid clutch):
1) Procure and install a fan shroud.  I assume this came with the car originally, but mine didn't have one.  Water pumps don't work very well without a venuri, so why should air pumps :-)
2) Check your timing.  If retarded too much, this will cause engine overheating.

I've been told by some restoration guys (Jaguar, Alpine Tiger) that flex-fans help stubborn cases with marginal designs (gee.. aren't they both British designs :-)

[J. Huber]

Hey PeterM,

Please don't let this discussion discourage you from checking the "usual suspects" that cause high running temperatures. It sounds like your car really gets warm ... While it may appear common, it is by no means normal for the temperature to go that high. The guage is telling you something, and my suggestion is you check it out (sooner than later!).

A good recore, new coolant and a new thermostat are a lot less expensive than a new cylinder head ...


James
63 230SL

[rwmastel]

James,

Hi.  In one of Jerry's posts, he says he has done the following:
- replaced the radiator
- checked the water pump
- checked the thermostat
- made sure that the radiator is as close to the fan as possable
- checked the ignition timing
- adjusted the idle mixture
- ensured that my spark plugs are of the correct heat range
- performed comprssion checks and leak down tests with excellent results
- he uses a mixture of water, water pump lube, and water weter
- his oil pressure is great at all speeds
- it makes no differance what rpm I hold the motor at during stand still

Can you think of anything he missed?

Rodd
1966 230SL Euro
1994 E420

[J. Huber]

Hey Rodd.

While just an owner and not a mechanic, I would say Jerry P has really covered his bases and his frustration is warranted ... Only thing I can think of is the head gasket may already be in trouble?

Just to be clear, my earlier response was toward PeterM, who seemed at a loss even before exploring his troubles. I have been there -- and I learned the hard way that that red needle is for real!!



James
63 230SL

[George Davis]

Jerry, a similar discussion to this is also going on at Dorian's web site.  One owner reported that his mechanic installed an electric fan in front of the radiator and a/c condenser, in line with the grille star/barrel.  Aftermarket electric fans can be had in either blow-through or pull-through configurations.

I agree completely with everyone who said that you don't want to hide a real problem by installing an electric fan, but it looks like your system is in top notch condition, and if still gets hot, then maybe the electric fan is only solution left.

My car has a rebuilt engine, a fairly new radiator, no a/c and a fan shroud.  Normally runs at 80 C, maybe up to 85, but when I got stuck in a huge traffic jam on an 85-90 F day, the gauge crept up to the top pretty quickly.  I don't think getting hot under these conditions is unusual... and frankly, I think the main reason newer cars don't heat up like this is... electric fans.

One comment though on your coolant.  I think I read somewhere that there is an optimal mix of anti-freeze and water for best cooling, something like 25% a/f and 75% water or thereabouts.  That might be worth checking out, though I doubt it will solve your problem.


George Davis
'69 280 SL Euro manual

[Benz Dr.]

Have to disagree here.
 A 250SL type oil cooler wil not add extra heat to the coolant. There will be heat pulled from the oil into the colant but that's where all the over heating is cooming from. Almost half the engine is cooled by oil and when you're not moving there's no air cooling the oil pan. The rad can handle the cooling of the water but not the oil. 280SL oil coolers work the same way and you need the fan shroud for these cars so air can be moved through the rad properly. The air oil cooler only works well while you're moving at enough speed for cool air to purge the heat out of the cooler and rad.
 The 250SL cooler is actually a heat exchanger and they do work. My car never over heats and it has a heat exchanger on it. I've driven 230SL's without coolers and at road speed on a warm day I could see the temp starting to creep up. This was on a freshly rebuilt engine with all new cooling system parts.
 If your coolant temp is 195F your oil temp could be 250F or higher. All that heat will start to move through the engine in slow traffic but by then it's heat soaked and only driving will cool it off. The condition of the cooling system can be determined by how fast the car heats up - a quick spike upwards indicates radiator problems. If it takes a long time to cool off or won't cool off during driving this is also a cooling system problem. Too many over heating cycles and you will always warp the cylinder head which results in a blown head gasket if left long enough.
 So the simple answer is that it's as much an oil cooling problem as it is a water cooling problem. Roll your windows down and turn off the A/C or you'll wish you did before too long. Remmber, these cars were designed without A/C in mind. They can handel it , but best not to push the limits.
Dan c

Daniel G Caron

[n/a]

Ahh.. interesting point.

Having owned a 911SC, I can definitively say that the engine oil carries ALOT of the waste heat.  It never overheated.  But then again it had a 10gt oil capacity with a wheel-well mounted cooler.

On a 280sl, the oil cooler is offset from the fan, so no air is pulled through it unless the shroud is in place.  There are some relief holes in the shroud to ensure increased air flow at speed, as well.

That may be the difference in my case.

I take it the 230 and 250 don't have an oil cooler.  Is the heat exchanger in the 250 a water jacket over oil pipe?  Were fan shrouds normally found on these two types?

My personal belief is that oil coolers are a good thing (as long as they cool) since the oil doesn't break down as quickly, and cooling is applied directly to the points of friction.  My caution had to do more with making sure that the problem is truly fixed, or you may end up with an expensive repair.