Recommendation for Aux. Cooling Fan for 280SL Auto & A/c

[hank sound]

Hey folks, Ingrid gets a bit warm during our So. Cal summer months, especially if we're sitting in traffic with the A/C blowing.   There are so many threads and posts regarding "overheating", but many of the cars discussed are equipped differently and the issues are different as well.   So please forgive, but I would like to see if I can get some advise in this, my thread

Benz Dr. (in one of those other threads that I came across) advised using a 79C thermostat for any Pagoda with Auto & A/C.    Thanks Dan, I'll do that.
So, what is the most agreed upon recommendation regarding the choice of an aux. electric fan.   I'm aware that Spal, Bosch and others, make many different electric fans, but you folks have done the dance - so that's where my trust lies.    Also, I don't need any elaborate activation device - - a simple switch is fine for me, so that when I flip it, I can then breath a sigh of relief   True, an engine temp sensor would eliminate "the switch" and is easy to install - - so that's OK too.  

Cheers & thanks, Hank

[Cees Klumper]

Before going with an auxilliary fan, have you tried Water Wetter yet? Additive to the coolant that's supposed to lower its operating temperature appreciably.

[hank sound]

Hi Cees,  Water Wetter is a normal part of Ingrid's "cooling diet".   Mind you, she doesn't overheat in most normal driving instances.   What I'm looking for is a "second level defense" alternative.   My modern day Audi can sit in one place for an hour, mid day in 100 degrees of heat - with the air on ..............with no increase in temp.    That's asking a lot of a cooling system in a 43 year old 280.   So, what we do is make what we got, work as good as it can.   Sometimes, we need help from some add ons (Water Wetter included).     What I'm looking for is the best fan available, to do the job that I may need it to do - - when I need it.

Cheers, Hank

[zoegrlh]

Hank, have you also thought about the "by-pass system" that some of our southern most members have put on their SLs.  It is a by-pass tube with valve that allows for the hot water to by-passing the heater core.  Your heater core even if the heat knob is turned off, will still flow hot water from engine.  This has caused problems of heat build-up in the cabin.
Bob

[zoegrlh]

Also Hank, Have you thought of having your radiator re-cored with the newer more efficient larger cores that still look originial.  I had mine done several years ago and have not had any issues with over heating, and the weather does get hot in Virginia too. A good example is this week 100s everyday.
Bob

[DavidBrough]

Hi Hank,

I have an early A/C equipped 280 which also suffered from overheating and it does seem that these models are the main ones susceptible to this problem. I eventually cured my issues by removing the original viscous unit and fitting 2 SPAL electric fans although it did take me quite a long time to get there.

I actually had overheating issues prior to fitting A/C and first tried a 3 core radiator, a heater bypass then a pusher fan in front of the radiator all of which made no difference at all. The problem with the pusher fan was the lack of space and the only fan that would fit was far too small to be effective. I must say that my car never actually overheated but the temperature did rise higher than I was comfortable with. The handbook supplied with my car when new does say that the temp could rise to the line above 80/180 on hot days in traffic but I was not happy to let it get that far.

When I fitted A/C I decided to go belt and braces and as there was even less space in front of the radiator with the condenser in the way I removed the viscous fan and fitted 2 SPAL electric units coupled to their programmable automatic fan controller which works a treat as this also switches on one of the fans when the A/C is on. Just to be sure I also fitted an electric water pump which is secondary to the standard unit and only used in case of emergency. If the engine should overheat I can activate the pump and the fans whilst the engine is off and the temperature is brought back to normal very quickly. Thankfully I have never had to use the pump in anger as the fans do the job well enough but I did need the extra peace of mind when I fitted the A/C. I think I could now remove the pump but I have decided I may as well leave it in place now.

In short, I think you will struggle for space in front of the condenser to fit a fan of sufficient power to make any difference on its own. However, if you also considered fitted an electric water pump then the two together with the engine switched off may give you the peace of mind you’re looking for. The electric water pumps are available from Davis Craig and fit into the bottom hose without any other brackets or modification and in normal use don’t impede the standard water flow at all. If you get into trouble you just need a single switch to activate both the fan and the pump (with then engine off) and the temperature should come back down quite quickly depending on the size of the fan you can squeeze in. Have a look at http://www.daviescraig.com.au/Electric_Water_Pumps-list.aspx

[mdsalemi]

My two cents: once I replaced my radiator, cooling has been a non issue.

However, I'm always intrigued by Dan Caron's analysis that the oil system does a large amount of cooling...

Something to consider is a larger capacity oil cooler, or additional work on the oil side of things.

[DavidBrough]

Hi Hank,

I attach a few photos of the fans I've tried, the Kenlowe was the first and it's a 12" in think which was the largest I could get in front of the radiator, the second was a 6" which again was the largest that would fit with the condenser in place, the final pic shows the water pump as fitted in the bottom hose.

[hank sound]

Hi David,  thanks for your response along with the pics of your various fan installations.   Picture #2 would be the most applicable in my case.   Question .. did you do any cutting on the body sheet metal just below the star and surround, to make the Kenlowe fit?   I'm sure it was very tight, and from the pic, I'm guessing (hope I'm wrong) you had to do a small bit of trimming.  

While rereading your post, I gather that ultimately, you selected dual Spal fans to replace of the single factory unit (along with your electric water pump mod) - - this all culminating in your satisfaction.   Would you please take a few pics of the "dual fan installation" and post them in this thread?   Also, can you share with me, the model numbers of the Spal fans that you settled on?

Thanks mate,

Hank

[DavidBrough]

Hi Hank,

I haven't done any body work modifications to fit the fans, I think from menory that I did have to shave a bit off one of the fans plastic casing to get it to fit but I think that was with the twin fan set up where they met in the middle as the overall width was a bit too large. I'll dig out some photos and the part numbers for my current set up and let you know.

[DavidBrough]

Hi Hank,

The fans I have fitted currently are as follows:-

VA26-AP50/C-44A which is a 280mm unit fitted as close to the top hose intake as it will go

VA11-AP7/C-57A which is a 255mm unit fitted between the above and the air cleaner side

FAN-PMW-V3 fan controller this is mounted by the screen wash bag

I attach a photo of the fan controller but I can't find any of the twin fans and my cars having some IP work done at the moment so I post some more pics at the weekend when I get it back.

[DavidBrough]

Hi Hank,

Here are some pictures of my twin fan setup. The idea with electric fans is to mount them as close to the top of the radiator as possible and the extra mounting holes one the right are were my attempt to do that but the bodywork got in the way.