Author Topic: Overheating Solution? (Read 58110 times)

DavidBrough · « **on:** October 01, 2006, 11:50:32 »

After experiencing the all too common overheating problems when stationary for some time I finally decided to try an electric fan which seems to have cured the problem and thought I would share the results as this may help others.

My engine was rebuilt recently and I took the opportunity to fit a three core radiator and felt that this would be the answer. Unfortunately not, after 15/20 minutes stationary at tick over in a 20deg plus garage up went the temperature heading straight for the red.

Popping the bonnet helped as did revving the engine to about 2,000 rpm but I was not prepared to put up with that. Once on the move temp always returned to normal within half a mile. All the usual settings for ignition timing, IP and linkage were checked and rechecked, the fan clutch was passed as healthy by the local cooling specialists who also carried out numerous tests as they were certain that it must be a head leak somewhere but all was OK.

Despite the fact that the UK is not that hot in the great scheme of things and my car does not have A/C It got to the stage where I could not trust the car in anything above mildly warm in case I got stuck in an all too common traffic jamb. I had to try an electric fan.

I purchased a 13” fan from kenlowe and my radiator guy soldered some mounting tubes through the radiator so I could mount the unit direct and easily remove it if needed. Finished fitting the fan today and let the car heat up to the mark just below red and switched on the fan. Within 4 minutes temp was back to 180, happiness.

I attach some photos of the installation which was quite straight forward. I favoured a simple manual on off switch to the automatic to keep it simple and let me be in control.

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waltklatt · « **Reply #1 on:** October 03, 2006, 09:34:10 »

David,
Looks as if you have the same setup with the electric fan as I have on my 220SL.
I would also be careful with the clearance between the fan and the grille.
I mounted the fan so that the moving part will be exactly within the barrel of the star on the grille.
I dont have a picture now, but can post one soon. I also mounted an evaporator in front of the radiator for the future installation of the A/C.
But this is a good idea to have a small electric fan in front to help our cars deal with the modern traffic and heat dissapation.
Walter Klatt
1967 220SL-diesel
1963 230SL-gas-sold

bsimaz · « **Reply #2 on:** October 03, 2006, 09:59:52 »

Are you sure that the radiator is clean (inside). When I recently fixed mine I had to have the radiator completely re-cored. Running it off and on while repairing the rest of the car, I let it idle in the garage for and hour or more. My temp never went above 180 (about 179 to be exact). It has never gone above that while driving either.

Bill Simaz
'66 230sl
Back on the Road

DavidBrough · « **Reply #3 on:** October 03, 2006, 10:54:13 »

Hi Bill,

I had a new radiator fitted with a three row core in place of the original 2 row which I though might help but didn’t. The cooling shop also re checked it when soldering in the mounting tubes for the fan and confirmed there were no blockages. From reading the many post on this topic it does seem that some cars are more prone to overheating when stationary than others and you are one of the lucky ones. I’m just glad mine doesn’t have to put up with 40 deg temperatures as some do. Once on the move the big radiator soon cools things down but when the temperature was over 30 deg, as it was here in the summer, it started to heat up quite quickly when stationery. I just needed some peace of mind and this seems to have done the trick.

David Brough

DavidBrough · « **Reply #4 on:** October 03, 2006, 11:21:12 »

One more thing whilst I think about it.

Last year I fitted heat tape to the exhaust front pipes which actually made a very significant difference by lowering under bonnet temperature. I think this may be more significant for RHD cars as the manifold exits forward. However, I had to remove it when I rebuilt the engine this year as I damaged it.

As it turns out that was a good thing as the front pipes had corroded quite badly under the tape and would not have lasted very long at all. I have a mild steel exhaust which is in reasonable condition. When I have to change it I will fit a stainless system and will try the tape again at that time.

If anyone is using heat tape on a mild steel exhaust you may well want the peel a bit back and check for corrosion as mine was really quite bad in 9 months and about 4,000 miles of use.

David Brough

rwmastel · « **Reply #5 on:** October 03, 2006, 14:14:21 »

quote:
Originally posted by bsimaz

... When I recently fixed mine I had to have the radiator completely re-cored ..... '66 230sl

Bill,

Our 230 engines don't typically have as much of an overheating issue. The owners can usually resolve them through "normal" means, like you did. The persistent & difficult overheating problem is with the 280 engine. Bigger cylinder bores + same block size = less space for cooling passages.

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

paulr · « **Reply #6 on:** December 07, 2006, 15:22:20 »

Hi David

I have a 280SL and was reminded of the overheating problem the other day in Piccadilly. I looked at the Kenlowe site then checked out your photos. How does this look with the grille back on? Does it show? Was this the best solution do you think?

thanks

paulr

paulr

paulr · « **Reply #7 on:** December 07, 2006, 15:51:17 »

Hi

I would really like to see this picture if it is available

quote:
Originally posted by waltklatt

David,
Looks as if you have the same setup with the electric fan as I have on my 220SL.
I would also be careful with the clearance between the fan and the grille.
I mounted the fan so that the moving part will be exactly within the barrel of the star on the grille.
I dont have a picture now, but can post one soon. I also mounted an evaporator in front of the radiator for the future installation of the A/C.
But this is a good idea to have a small electric fan in front to help our cars deal with the modern traffic and heat dissapation.
Walter Klatt
1967 220SL-diesel
1963 230SL-gas-sold

paulr

DavidBrough · « **Reply #8 on:** December 08, 2006, 06:33:23 »

Hi Paul,

I’m not sure the electric fan is an ideal solution as you can see it through the grill, I will take a photo and post it, but in my case it does seem to work and I’m not worried about being stuck in traffic anymore.

David Brough
1969 280SL

DavidBrough · « **Reply #9 on:** December 09, 2006, 04:59:56 »

Here are some photos of the fitted fan with the makers sticker and, after removing the sicker and painting the centre mount black. It was very visible to start with but once the sticker was removed and the centre painted black it's not too bad. I took pics with and without flash although the real world visibility is much closer to the non flash pics.

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David Brough
1969 280SL

paulr · « **Reply #10 on:** December 09, 2006, 10:35:57 »

thanks David for the photographs, they really are helpful. I suppose it's not too bad and as I really can't stand the 'will she boil over' tension I feel in traffic much longer and as I live in central London, I'll probably have one fitted too. I will sleep on it for now.

Nice garage..I've lived in apartments smaller than that!

paulr

jeffc280sl · « **Reply #11 on:** December 09, 2006, 11:23:38 »

I have a fan like David's and I suppose it is helps some. What happens if you open the valve for the heater core? I have added T fittings to both the inlet and outlet hoses of the heater core. I connected an hose between these fittings which allows hot water from the head to bypasses the heater core and cycle through the cooling process full time. Heat works as before although I can't say for sure if it is sufficient in very cold weather. A shut-off valve placed between the two fittings would solve that issue. One would need to manually open the valve in late fall and close it in the spring. The cooling performance of the engine is significantly improved with the bypass hose and fittings.

Jeff C.
1970 280SL 4-speed

Kenneth Gear · « **Reply #12 on:** December 09, 2006, 20:22:56 »

Thanks for posting the pics. It looks good to me and as a driver of a car that has overheated regularly, I know how frustrating it can be and you solution is well worth achieving peace for mind. Enjoy!

Ken G
1971 280 SL
Silver/red

waqas · « **Reply #13 on:** July 04, 2007, 14:49:11 »

Hello,
Besides the manual on/off switch for this auxiliary electric cooling fan arrangement, has anyone connected the fan to some kind of temperature sensor controlled switch? This would prevent the driver from having to manually turn on the fan (especially if someone unfamiliar with this 'feature' is driving the car). I have an electric fan I want to install in front of the condenser, and I'd love to hear more about how this was wired into the system.

In addition, if the temperature sensor switch is installed such that it bypasses the ignition switch, then it would keep the fan running after the car has been shut off. I'm sure everyone else here has seen their car temperature climb up after the engine has been shut off. A temp-controlled switch would keep the electric fan running for a bit longer after shut-off and prevent the engine temp from rising too close to the red...

WAQAS in Austin, Texas

jeffc280sl · « **Reply #14 on:** July 04, 2007, 19:38:22 »

My fan is controlled by a thermostat like the one you desire. It works fine but the fan itself provides marginal cooling. My wife's ML has a electric fans and and an electric water pump. Sometimes after the engine is turned off I can hear the puimp running for a short time. This is another area for me to look at sometime in the future.

Jeff C.
1970 280SL 4-speed

waqas · « **Reply #15 on:** July 04, 2007, 22:20:12 »

Jeff, absolutely brilliant idea!

An electric water pump would actually help in all areas:
(1) While idling in hot traffic, lots of water-flow would keep engine temperature hikes in check (no need for revving the car up to 2000rpms while stopped at a light).
(2) After shutting off the engine, water flow would very quickly cool down the engine, conserving the battery (a lower water pump speed after shut-off would conserve battery power too).

Questions that need answers:
- Is there an electric water pump that would fit in the existing pump housing? (or perhaps we can fabricate an 'adapter'....)
- Would an electric water pump provide the equivalent water flow, as compared to the stock pump, at high RPMs?
- I presume one would use a different alternator belt (bypassing the water pump entirely)
- Power requirements: would it be wise to upgrade the stock 35A alternator to something more, say 55A? I was wondering about this for the addition of the electric fan as well. Of course, an electric water pump would be much more effective!

Have we missed anything?

This is a very very compelling idea... has anyone ever tried it?

WAQAS in Austin, Texas

jeffc280sl · « **Reply #16 on:** July 05, 2007, 07:15:36 »

These are interesting questions. I think my ML as an auxillary electric water pump. Meaning there is a belt driven pump also. It is my belief the aux electric pump helps to cool the engine after shut down by continuing to circulate very hot water through (some part or all) the system. I don't know if it operates while the engine is running. Your idea goes a step beyond and suggest a full time elctric water pump in place of the mechanical one.

Jeff C.
1970 280SL 4-speed

DavidBrough · « **Reply #17 on:** July 06, 2007, 11:48:10 »

Electric water pump, what a neat idea. Had a quick look on the web and these people seem to do quite a few. Just search on electric water pump.

www.burtonpower.com

Would be interested to hear any other thoughts.

David Brough
1969 280SL Auto (with A/C almost)

Raymond · « **Reply #18 on:** July 08, 2007, 07:39:48 »

For those of us with air conditioning, there isn't room for this fan between the condenser and the grille. Has anyone done away with the fluid clutch and fan and put electric fans between the radiator and engine?

Ray
'68 280SL 4-spd Coupe

jeffc280sl · « **Reply #19 on:** July 08, 2007, 08:34:27 »

Ray,

What is a fluid clutch?

Jeff C.
1970 280SL 4-speed

bpossel · « **Reply #20 on:** July 08, 2007, 10:06:22 »

Jeff,

That's the Visco fan clutch...
Bob

quote:
Originally posted by jeffc280sl

Ray,

What is a fluid clutch?

Jeff C.
1970 280SL 4-speed

bpossel (Memphis, TN.)
'71 280SL / '97 E320

DavidBrough · « **Reply #21 on:** July 08, 2007, 11:14:46 »

Hi Ray,

I’ve just fitted A/C and have had to remove the blower fan I fitted in order to mount the condenser. I found mention of a Spal puller fan in a previous post that some of our German friends have successfully used to replace the standard viscous unit so I’ve ordered one. The part number is VA18-AP51/C-41A which has a 63mm depth and should just fit. Unfortunately it will take about a month to arrive as this is a special order part in the UK. Will let you know how I get on.

David Brough
1969 280SL Auto

pch90265 · « **Reply #22 on:** July 09, 2007, 00:40:00 »

Hi,
I have the overheating issue with my '71 280sl only when I am stuck in traffic for quite a while. I have read the posts about putting in a 3 core radiator and changing the fan. I have A/C in the car which I don't particularly use but do not wish to remove the condensor as some have suggested just yet.

Where can I order this larger capacity radiator & fan from? Thank you for your suggestions.

Bert
'71 280sl (auto-A/C)

bpossel · « **Reply #23 on:** July 09, 2007, 05:31:09 »

Hi Bert,

I purchased and installed an after market high efficiency radiator and it didnt help much. I then took my original MB radiator to a local radiator shop and had them add the extra core. Using my original radiator with an add'l row has worked well and is what I would recommend.

I also installed a new Viso fan clutch (fan). Purchased from Arizona Autohaus (https://www.autohausaz.com). They have it listed currently for $162.

Good Luck,
Bob

quote:
Originally posted by pch90265

Hi,
I have the overheating issue with my '71 280sl only when I am stuck in traffic for quite a while. I have read the posts about putting in a 3 core radiator and changing the fan. I have A/C in the car which I don't particularly use but do not wish to remove the condensor as some have suggested just yet.

Where can I order this larger capacity radiator & fan from? Thank you for your suggestions.

Bert
'71 280sl (auto-A/C)

bpossel (Memphis, TN.)
'71 280SL / '97 E320

waqas · « **Reply #24 on:** July 09, 2007, 17:40:20 »

quote:
Originally posted by jeffc280sl

These are interesting questions. I think my ML as an auxillary electric water pump. Meaning there is a belt driven pump also. It is my belief the aux electric pump helps to cool the engine after shut down by continuing to circulate very hot water through (some part or all) the system. I don't know if it operates while the engine is running. Your idea goes a step beyond and suggest a full time elctric water pump in place of the mechanical one.

Jeff C.
1970 280SL 4-speed

Actually, that's what I thought you meant in the first place. However, installing the pump as an auxiliary unit may have it's own advantages. In the case of adding another pump as an auxiliary unit, some questions:

Where does it get attached? (in the head-to-heater-core outlet path, perhaps? This assumes that your neat trick of bypassing the heater core is employed...)
If so, it's temperature control mechanism would need the heater lever to somehow also contribute to switching it on/off)
Would one pump running in 'series' with another alter the flow of the other? In other words, once the engine is switched off, would the electric pump be strong enough to pull water past the now-stationary mechanical water pump? (or is there some other way to bypass the flow)

This is getting complicated, but good food for thought. Once I've sorted out my radiator re-coring project, I'll have to revisit these ideas...

WAQAS in Austin, Texas

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