I need the forum's input on manual engine cooling
 

I have this idea that I think would be great, but I want to get the forums input first. Its to manually cool the engine with a mist of water being sprayed across the radiator. The idea occured to me when my temp gage goes up to about 100C. I live in the desert and so its around 105 here and my car gets really hot, especially with the a/c on. So I came up with the idea to disconnect the windshield washer nozzles and attach a fine tubing the length of the radiator and run it acoss the top of the radiator before the fan. The tube would have tiny holes in it for the water to come out. The windshield wiper tank would be filled with distilled water and the windshield wiper motor will of course be disconnected of course, so when I press the button that sprays the water a thin mist will br produced right in front of the radiator and the fan will act as a dispersion mechanism that will disperse the mist to cool the engine. Anyone have any input on this idea? Or has anyone tried this?

This would work, the turbo guys do it with intercoolers, but I'd be more tempted to use other means of cooling first. ( your idea of using distilled water is a good idea to prevent mineral build up. )

In order to take some of the load off the A/C, make sure the heater valve shuts off water flow. Feel the heater hoses, ( careful,might be very hot ) if they are as hot as the uper rad hose, you have water flow that needs to be stopped.

On my 97 SL 320 I added a valve to the heater water supply. The stock system has a valve on the outlet but the heater core has small bleed line. This allows hot water to circulate and bring heat into the cabin. Something you want to avoid is to completely isolate the heater core as expansion of water might cause to burst. ( not likely but possible )

The added valve is a good quality plumbing type 3/8" pipe thread ball valve coupled to a 3/8" pipe 6" long cut in half. A 3/8" pipe is just over 5/8" OD making it a good fit for either 5/8 or 3/4" hose. I think it is a bit of a stretch for our metric hose but a little bit of carb cleaner spray on the hose ID does the trick. I add a heater valve to all of my cars / trucks. It makes a huge difference on the ones that don't have AC.

My SL also has / had heated windshield washer tank and heated wiper park location. While both of these have a thermostat, taking them out of the loop made for less chance of leakage.

Another thought would be to install well a guarded heater core under the bumper but in the air flow. This would help a bit but I'm not sure if it will make enough difference.

Is the A/C condenser / rad clear of leaves and bugs? Take a look between the condenser and rad for any clogs.

Air flow across the condensor & radiator is very important in cooling & a/c operation.

Does your car have 1 or 2 fans on the condensor?

Do you have them running on high speed with a/c operation?

I have 2 fans and when I turn the ac on the fans come on at med or low speed. but once the temp rises to 105°C the high speed fans kick in. I know that I can disconnect the 2 prong temp sensor to the engine block and have them always running at high speed (over cooling would not be an issue as the normal outside temp where I live is triple digits 100°+), but I am not sure about the effect of the electric fans constantly running. my condenser and radiator were both replaced less than 6 mos ago, and I serviced my electric fans by taking them apart and cleaning them and greasing the parts that created friction with electric grease and they work great.


97 SL320, my heater core is disconnected, so no coolant runs to it. I have a ball valve in place of the aux water pump as I didn't need that either.

On cars in HOT areas, I would suggest allowing the fans to run on high speed with a/c operation as well.

Are you running 100C with the A/C off too?

Ismalley,
For what it is worth, I live in the Palm Springs area. I had Jim Forgione make a special resistor that turns on the dual aux fans at 90C My car always runs in the 85-92C area. yes, the fans are on most of the time but like you I have a guy who rebuilds motors quite reasonably. In October, I simply pull the added resistor and return to normal operation.
Anziani
'93 320CE
'95 E420

Ps2cho, not 100 with ac off, only when its on.

Aziani, how much was the resistor?

They are $79 + shipping. Here is his site: K6JRF Auto Page

Anziani

Bought the resistors at radio shack for $1.40. I have the 1k ohm resistor, but what do the different ohm numbers mean? I.e., 5 ohm, 1m ohm, 100k ohm, etc. They had a lot to choose from. How do the xx ohm numbers correspond to the temp at which the high speed fans turn on? Thanks.

You need specific resistor values for the engine temperatures you want. That is why I suggested Jim Forgiones page. He has the values figured out and has put together a "harness" that snaps on to the exisitng switch.
Anziani

You can also just wire a switch in parallel across the temp sensor that kicks the aux fan on high speed.

On my 91 300TE, I threaded a wire from the temp sensor through the firewall to the console, and installed an extra Rear Overhead Light switch there. I turn the fan on high whenever I want :-)

added the resistor across the temp sensor, fan cuts on at high speed around 90°C. Problem solved. Thank you all for the help and input.

Back in the 6os, stock car racers would increase engine cooling by running tubing from the water pump around three sides of the engine bay and then back to the radiator. I don't know in how much increased area a stock water pump could effectively work for everyday use, but it might be worth a try.

bumping this thread since I may end up doing this.

Found this:

He actually uses an MB pump:

Radiator Mist - beat the overheat - YotaTech Forums

does anybody know if the cool harness works when plugged into the green 3-prong sensor? Jim Forgione's instructions only mention to find the blue 2-prong sensor, but my car only has the 3-prong one.

If you have an overheating problem, you would be much better served by finding the cause of the problem and curing it. If you do NOT have an overheating problem, be happy and don't worry about it.

After running with the resistor for about 3 weeks I realized that my ac would cycle off and on.....wasn't sure what the problem was at first, but it was cycling of and on every 30 sec to a minute. I removed the resistor yesterday and now the compressor stays on and car gets extremely cold. I will leave off the resistor. The engine temp does still rise once again to about 105-110*C, but when I'm driving with an outside ambient temp of 114*F I'd much rather be cooler.

Manual engine cooler complete!
 

Ok guys, last summer I talked about making this manual engine cooler and I have done it. I alson have the manual high speed aux fan switch on my dash which also helps. Here are some pictures....as a side note, the pictures show only one vinyl tube feeding between the radiator and condenser, but I have installed a second washer pump into the washer reservoir port that was plugged with a closed rubber grommet, now I actually have 2 pumps and 2 hoses going between the radiator and condenser that spray water. When I use this in conjunction with the high speed fans it lowers the temp of the engine below the 100*C mark even wih the a/c on and the outside ambient temp at about 110*F. Only need to press the button a few times or either hold the button down for continuous water injection if the temp gauge is really high and the engine temp will begin cooling down within 20-30 seconds. I had to splice into the plug to add the second washer pump, since I took out my aux water pump, I used that harness since it is the exact same plug as the washer pump plug. I plugged the ends of the clear tubing and puncturd holes randomly on all sides of both holes to get better water misting/dispersion and to avoid having hot spots if I would've made the holes uniform.

nnice Ismalley. Are you running a m104 or 103 turbo? did you go to colder spark plugs?

It would be pretty cool if you automated it, when engine temp = X, spray on the radiator for X seconds.

Not for intake or turbo....I did this because of the climate I live in and the outside ambient temp can reach 120* on some days, but mostly triple digits are a bit lower. So what this does is when my engine starts to get hot, I press the button and it shoots a dispersed mist of water filling the area between the radiator and condenser and the fans pull in the cooler air/water and cools down the engine.


James Dean, I agree, but I like having the manual controls because sometimes its just a few squirts and other times I'll hold the button down for a few seconds giving the radiator and condenser a nice spray to help bring the temp down faster.

I see no reason why you couldnt have both automatic spritzing and manual. I think it would be a fun project to do.

How long do you hold the button down for and how long does it take to achieve a good temperature? Like if it was a 100C, how long would you hold it down for until it reached 80C?

For the temp to drop down 20* I can hold the button down for about 10 seconds with high speed fans on and the temp would be down 20* in about 30-45 seconds. Never really timed it, but it drops pretty quickly. I just added another legnth of tubing to it and now I have tubing running between the radiator and condenser in a sort of an "S".....going back and forth. In the picture the red and blue lines represent the hoses between the radiator and condenser. Water sprays out from the entire legnth of the hose through tiny holes that create the mist that brings the temp down. Very easy to do. Just use distilled water to avoid mineral build up.

I went from water pump fan to electric on my 300SD I hardly use the fan except when in the city,and its manual.I'm doing the same for my W140

Latest upgrade to manual cooling
 

So instead of running the tubes between the radiator and condenser I decided on another upgrade. I purchased 2 180 degree sprinkler nozzles from Lowe's with a 1/4 inch diameter barbed fitting and I purchased 1/4 inch clear tubing. I mounted the nozzles over the radiator and condenser pointing downward between the fans and now I get a nice uniform, spray that covers the entire radiator and condenser with considerably more with than my previous set up. Cooling the engine now takes less time. included are some photos and a diagram.


Materials used: *For dual nozzles, this can also be accomplished with one nozzle*

1.) 1/4 inch diameter clear tubing (legnth depends on diastance from washer reservoir to radiator)

2.) 2- 180 degree plasic sprinkler heads with 1/4 diameter barbed end

3.) Zip ties

4.) Check valve and Y- splitter tubing (optional)