Oil/Coolant Heat Exchanger/230SL Upgrade

[JPMOSE]

I am going to start on my next project: the cooling system.  Besides all hoses and clamps, I am going to have the radiator rebuilt (although it doesn't seem to need it -- just looks bad; reverse flush the heater core and install new seal; install new thermostat; and possible water pump replacement.

The 250SL (and I believe late 230SLs) have an Oil/Coolant Heat Exchanger (Exchanger) underneath the injector pump.  Could I get a data dump on the following questions:

1)  How exactly does this work (other than the obvious)?

2)  Is there any service required on the Exchanger other than the normal coolant flush performed on the entire system?

3)  What is the life expectancy on the Exchanger and has ANYONE ever had one rebuilt  (they are around $1,000 new)?

4)  Is the oil cooler (air-cooled) on 280SL superior to the subject exchanger?


Thanks for your time!

Best Regards,

J. P. Mose
1968 250SL

[rwmastel]

quote:Originally posted by JPMOSE

The 250SL (and I believe late 230SLs) have an Oil/Coolant Heat Exchanger (Exchanger) underneath the injector pump.

Huh?   :?:

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

[TA250SL]

I have the same oil cooler as described, and had a leak repaired by a local radiator shop.  It should be good for another 40 years.

Tom
Early 1967 250SL
Euro version    
Los Angeles

[rwmastel]

JP and Tom,

So, I'm supposed to have some device below the F.I. Pump that has engine oil running through it in one part and engine coolant running through it in another part and the heat is transferred between them?  Do you have a picture??

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

[mulrik]

Yes I think these are very good questions. I have attached a picture of it for your sake Rodd ;-)


Download Attachment: 218230.jpg
12.18 KB

'67 250 SL Papyrus White 113043-10-000023

[Benz Dr.]

The oil cooler was an option on 230SL. All 250SL's have oil coolers under the injection pump. These are really heat exchangers as they heat the oil up faster in a cold engine yet cool the oil in a hot engine.

Dan Caron's
 SL Barn
benzbarn@ebtech.net
 slbarn.mbz.org
  1 877 661 6061

[66andBlue]

quote:Originally posted by Benz Dr.
The oil cooler was an option on 230SL.

Dan,
if a 230SL didn't come with this option do you recommend to retrofit it with this oil cooler?  Or are there better options now available for the 230SL?

Alfred
1966 blue 230SL automatic

[Benz Dr.]

That IS the only option you can easily use on a 230SL. You need the oil filter housing, oil lines, oil cooler, coolant line that runs around the front of the oil pan and a small Y shaped pipe near the intake manifold so you can plumb the cooling lines all together. There is also a pipe fitting that scres into te side of the engine block just behind the injection pump. Removing the old plug from the block could prove challenging.
All these parts can be found used. Make sure the cooler holds at least 100 PSI pressure on the oil side. The pressure relief valve will open before that but I think you would be wise to have a margine of safety. I've never seen one leak though.

Dan Caron's
 SL Barn
benzbarn@ebtech.net
 slbarn.mbz.org
  1 877 661 6061

[Naj ✝︎]

Bits needed to make up exchanger kit:

Download Attachment: DSCN0255.JPG
29.78 KB

+ engine block adaptor and hoses, clips etc.

naj

65 230SL
68 280SL

[ja17]

Hello Naj,

Thanks, a great photo. You cannot get such good information anywhere else but right here on this site!

Joe Alexander
Blacklick, Ohio

[66andBlue]

Hello Naj and Dan,
thanks for the picture and the instructions how to build one. But I'll pass on that thrill - that's way too much for my skills!

Alfred
1966 blue 230SL automatic

[n/a]

JPMOSE

Just  for information sake, the same oil/coolant heat exchanger can be found on other MB automobiles of the era.  I took one off of a 67? 250 SE sedan.  You may be able to find one on other models from the late 60's as well.  Just look around.

Good luck

Iverson

[ja17]

Hello,
Yes the same oil cooler was standard equipment on the 250S and 250SE sedans (W108) 1965 to 1967.

Joe Alexander
Blacklick, Ohio