230sl -> 280sl Cooling System

[captainslow]

Hello,

I was wondering if anyone has played around with swapping out the noisy 4 blade fan on the 230sl to the 280 vicious coupling and fan?  Is swapping over to the 280 setup as simple as swapping the water pump to the shorter 280 style and changing the pulley to the 280 variety?  I'm a big fan, pun intended, of thermostatically controlled fans and shrouds.  If the fan diameters are the same i would also think i could use the 230sl fan shroud and placement, as far as depth, would be relatively correct.  Any guidance would be appreciated!

[captainslow]

I see this isn’t a very popular idea. Can anyone tell me if the 280 water pump will bolt onto the 230 water pump housing? I can figure it out from there! Just looking to gain a few inches for the clutch!

[dirkbalter]

Hi captain,
I am in the process of doing that as well, hoping to achieve the best cooling set up. Be careful with the waterpump housing. Even though I soaked them in WD-40 prior, 4 of the five bolts snapped off when trying to remove them. As you already mentioned, you need a 4-bolt pulley. I am using the long style 280 waterpump. Not completely sure but the short style was used on the 250's with a spacer. Others may want to weigh in here.

[captainslow]

Hi Dirk,

Maybe consider replacing the bolts with shouldered studs with a socket head at the end of them so the part in the water pump housing never needs to spin again.  If I can find something from ARB or the like I'll probably take that route.  I imagine any of the corrosion on the bolts seizes as soon as it hits the aluminum casting.  At the bolts blind or are they inside the water jacket?

I'm opting for the short one because I can always add length with a spacer or adapter to single nut thermostatic fan clutch if I can't get one I like with the correct bolt pattern.  Are you using a 280 water pump pulley?  I was wondering if there was a diameter change between the 230 and 280 to accommodate for the lack of 100% engagement to mess with the pump curve of both the fan and the water pump, or if they 230 vs 280 accessory pulleys/crankshaft pulley was even in the same plane. 

Are you also planning on running with or without a shroud?

[dirkbalter]

Hi Dirk,

Maybe consider replacing the bolts with shouldered studs with a socket head at the end of them so the part in the water pump housing never needs to spin again.  If I can find something from ARB or the like I'll probably take that route.  I imagine any of the corrosion on the bolts seizes as soon as it hits the aluminum casting.  At the bolts blind or are they inside the water jacket?

I'm opting for the short one because I can always add length with a spacer or adapter to single nut thermostatic fan clutch if I can't get one I like with the correct bolt pattern.  Are you using a 280 water pump pulley?  I was wondering if there was a diameter change between the 230 and 280 to accommodate for the lack of 100% engagement to mess with the pump curve of both the fan and the water pump, or if they 230 vs 280 accessory pulleys/crankshaft pulley was even in the same plane. 

Are you also planning on running with or without a shroud?

The treads in the waterpump housing are through and exposed the water from the back. I agree, studs would have been the better way to go. I did the waterpump on my 108 a little while ago and the bolts came out fine. I will try to drill out the screws on the 230 housing and re-tap or put inserts in to fix it. But just in case I screw up, I bought a new housing as well.
I have an identical 4-bolt pulley with the same pitch dia and face depth as the original 3 - bolt. I also have a dual pulley 4-bolt from a sedan that has a shorter face distance??

Reading through the threads, I am not sure how efficient or helpful a shroud is. I also don't have one (yet). Living in socal, I will add AC (a modern, rotary type) and utilize the "bigger" 230 radiator in conjunction with a 250 external oil cooler.

Where did you get your shroud?
 
 

[WRe]

Reading through the threads, I am not sure how efficient or helpful a shroud is. I also don't have one (yet). Living in socal, I will add AC (a modern, rotary type) and utilize the "bigger" 230 radiator in conjunction with a 250 external oil cooler.

Where did you get your shroud?
 

Hi,
some weeks ago I made some tests with an original metal fan shroud and the distance of the fan to the radiator and I can say that the performance increases a lot with shroud and minimum distance.
The original shroud is rare or expensive but the shroud from a W108 4.5 (A1095050855) can be modified very easily. 3 of the 4 bolts fit directly, the 4th need a new hole and the shroud needs some adjustment in the area of oil cooler hose mounting and in some edge.
https://www.sl113.org/forums/index.php?topic=27865.msg200589#msg200589
...WRe

[captainslow]

Dirk,

I nabbed my shroud from Bud's Benz it definitely wasn't cheap, 325 bucks for plastic! I actually haven't seen it personally yet.  I had it shipped to The Brassworks where I'm having the radiator "restored" and changed over to a modern higher efficiency core design.  The radiator needs the threaded tabs to mount the shroud since my 230 never had a shroud from the factory.  They did a great job on making me a new heater core to replace my leaky one, at a much more reasonable price than MB, so I have faith in them making it all work!

I'm planning on just going through the Hayden fan clutch catalog and finding a "heavy duty" application clutch and modifying mounting to make it work.  As for the pulley I might end up having something made or scouring a catalog if I can't find a 280 short pump pulley.  I'll gladly disclose my recipe with part numbers if I can make it all work!

@WRe, optimum fan placement should be about the middle of the exit of the shroud.  Too far in there is more turbulence, too far out you are just moving air around in the engine compartment.  Depending on how tight the shroud sits to the radiator some high temp silicone foam tape at the contact points would insure that the air is drawn through the radiator and not from the sides.  Im shooting to have about 20mm of clearance between the surface of my clutch at the radiator.  I'll spec the clutch so it ends up halfway out of the shroud.

[Benz Dr.]

All this for a 230SL? This engine isn't noted for running hot because there's plenty of coolant flow through the block. Kind of like overkill and mostly a waste of time.....

I use a bit of heat on the screws going into the water pump housing. Thread sealer or anti-seize on the threads before assembly.

[dirkbalter]

I use a bit of heat on the screws going into the water pump housing. Thread sealer or anti-seize on the threads before assembly.

You are right, a little heat might have helped. I guess I was spoiled from the other one coming apart fairly easy. 

[dirkbalter]

Hi,
some weeks ago I made some tests with an original metal fan shroud and the distance of the fan to the radiator and I can say that the performance increases a lot with shroud and minimum distance.
The original shroud is rare or expensive but the shroud from a W108 4.5 (A1095050855) can be modified very easily. 3 of the 4 bolts fit directly, the 4th need a new hole and the shroud needs some adjustment in the area of oil cooler hose mounting and in some edge.
https://www.sl113.org/forums/index.php?topic=27865.msg200589#msg200589
...WRe

@ WRE, thank you, I have to check my radiator (230) to see how I can fit a shroud. I believe yours is a 280. right? If I understand you correctly, you are running an electrical fan only. (No fan attached to the water-pump)?

@captain. I am aware of the buds benz shroud. They sell one specific for a 230. Assuming that's the one you bought, I am surprised that you still have to modify the radiator itself? Would you do me a favor and post or send me some pictures of your final radiator / shroud assembly? FYI, I installed the (long) water pump with the pulley yesterday and the v-groove line up is perfect. You will need a spacer covering exactly the difference between the pumps to get your groove line up. BTW the pulleys show up quiet frequently on e-bay. $40 -50 typically.

[WRe]

Hi Dirk,
Yes,  mine is a 280, could be different to your 230.
With my tests I changed my electric fan with W108-plastic shroud, which wasn't necessary because the electric fan had his own shroud, back to original visco fan with original metal shroud.
Up to now I'am very satisfied, but still without a critical situation (e.g. stop-and-go traffic in the heat). Test will go on.
...Wolfgang

[dirkbalter]

Hi Dirk,
Yes,  mine is a 280, could be different to your 230.
With my tests I changed my electric fan with W108-plastic shroud, which wasn't necessary because the electric fan had his own shroud, back to original visco fan with original metal shroud.
Up to now I'am very satisfied, but still without a critical situation (e.g. stop-and-go traffic in the heat). Test will go on.
...Wolfgang

Thanks, I have a similar issue on my 108, (stop and go in heat). The 108 has am original electric fan (AC) in front of the condenser /radiator. I added a manual switch to run it at any time. This fan doesn't really seem to help much.

[WRe]

Hi,
my electric fan wasn't too bad in critical situations but not the golden solution.
...WRe

[GM]

I'm sure this won't generate any opinions but I'd like some anyway...
For those of us who have issues with our 280s overheating in stop and go traffic, despite all efforts made to resolve it, what is the thinking behind using exhaust manifold heat wrap? According to this article, "Using a base fiberglass weave along with proprietary materials, exhaust wraps can reduce underhood temps by as much as 50%." Really?
https://knowhow.napaonline.com/heat-management-how-to-install-exhaust-heat-wrap/
It's obviously not for a concours car or car shows, but for regular driving, in warm/hot climates, is this a potential remedy?

[captainslow]

I’d personally recommend having it ceramic coated if the manifolds are being removed from the car. I had a Stahl header ceramic coated for my 74 bmw 2002 I used to have and I gave it two thumbs up. If I ever have to take the exhaust manifolds off my car that’s what I was planning on doing!

[GM]

I was wondering about wrapping the manifolds while on the car

[bracurrie]

What impact would the thermostat have on cooling? Back in the day, there was a recommendation to change thermostat seasonally.
Also, the ratio of coolant to water can have an impact here.  Water exchanges heat better than coolant, but coolant can fight boiling over.
I just drove 80 mph from Memphis to Nashville on a 90 degree day running AC and the engine temperature was just under 220.  I pulled off and stopped at a light for several minutes and the engine temperature rose to 220 where it peaked until I was back on the expressway and it took 5 miles or so at 75 mps before the temperature returned to just under 220.  I believe this is normal.
I can remember when I was a kid that my father wouldn't change to winter thermostats and the engine temperature wouldn't get hot enough to heat the car well when the ambient temperature was below 15F.
It was recommended that I get a thermostat for the OM 617 and mod it for by-pass flow.  It has worked very well in cold weather keeping the engine temperatures up and it seems to work well when things heat up.

[Benz Dr.]

What impact would the thermostat have on cooling? Back in the day, there was a recommendation to change the thermostat seasonally.
Also, the ratio of coolant to water can have an impact here.  Water exchanges heat better than the coolant, but coolant can fight boiling over.
I just drove 80 mph from Memphis to Nashville on a 90-degree day running AC and the engine temperature was just under 220.  I pulled off and stopped at a light for several minutes and the engine temperature rose to 220 where it peaked until I was back on the expressway and it took 5 miles or so at 75 mph before the temperature returned to just under 220.  I believe this is normal.
I can remember when I was a kid that my father wouldn't change to winter thermostats and the engine temperature wouldn't get hot enough to heat the car well when the ambient temperature was below 15F.
It was recommended that I get a thermostat for the OM 617 and mod it for by-pass flow.  It has worked very well in cold weather keeping the engine temperatures up and it seems to work well when things heat up.

220F is far too high to run at for any prolonged period of time. 180 - 190 is the normal operating range for our cars. Modern engines run at higher operating temperatures but we should never compare the two.  Running at 220F will result in a warped cylinder head.

[doitwright]

A few measures others have taken to reduce operating temperatures but not mentioned in this thread are:

Radiator recore

Heater core by-pass

Electric water pump