M119 cooling upgrade? (Running electric fans sooner)

[Goran124]

Hi,
I have upgraded cooling system on all my E36 AMG cars, new thermometer housing with screew for air bleed, thermometer that opens on lower temp and 1 kiloohm resistor on temperature sensor to make fans kick in sooner…
And i really satisfied with result.

Now i would like to put resistor on sensor on my M119 cars so fans kick in sooner, does anyone know how to connect resistor on which senzor? Look at the pic.

Thx

 

[gsxr]

Search for "Cool Harness" to find the information you are looking for.

As I've explained in the past, I am NOT a fan of this modification on the 124 chassis, including the 034/036. If the cooling system is in good condition and viscous fan clutch is engaging properly, there is no reason the very loud electric fans need to run on high speed. Depending on the exact resistor selected, you can also end up with the electric fans never shutting off after they turn on high speed. Another negative, in cool weather with the heater engaged... the auto climate control will ramp up the fan speed on "auto" setting before heat is available - blowing cold air when you want heat. A couple cars I bought had this resistor / CoolHarness modification and I ended up removing it.

If you want better cooling, replace the mechanical fan clutch with a factory MB PWM electric fan from a mid/late 2000's model and use the MicroAutonomations controller. Search the forum for details on that as well.

 

[Goran124]

I know what you mean, but i have over 20 collectors cars, and once a month i drive each one of them.
When i drive E36 AMGs and outside is 35-40 celsius temperature gauge stays in the area between first line above 80C mark(i think that line is 100C) and 120C…and i end up watching at it all the time, i dont feel comfortable.
After i have upgrade cooling on those cars the temperature gauge is allways between 80c and first line above(100C) and it is much more relaxed to drive…i just feel better.
Thats all.

I dont drive them during winter, maybe on really dry and hot sunny days…so heating is no problem for me.

Thank you for the help.

 

[gsxr]

If the engine temp is consistently above 100°C (the unmarked line)... and anywhere near 110°C something is wrong with the cooling system.

If running the electric fans makes a difference, that means there is inadequate airflow, which means the viscous fan clutch is not working as intended. Making the electric fans run is a Band-Aid, not a fix. But, it may help out on some cars, if you don't mind the noise. I don't like the loud fans running all the time.

 

[Goran124]

The cooling system is perfect, all is like new, M104 3.6 just run hot on 40C, they are just like that and that is all good. Mercedes made them like that but i just dont like it…

 

[yao500e]

Hi,
I have upgraded cooling system on all my E36 AMG cars, new thermometer housing with screew for air bleed, thermometer that opens on lower temp and 1 kiloohm resistor on temperature sensor to make fans kick in sooner…
And i really satisfied with result.

Now i would like to put resistor on sensor on my M119 cars so fans kick in sooner, does anyone know how to connect resistor on which senzor? Look at the pic.

Thx

View attachment 217334

I am looking for ways to run cooler on my C36 with same M104 engine as your E36.

Did you install 71 degree thermostat?

also, how and where did you install 1 kilo ohm resistor on the temperature sensor?

thank you.

ps. im considering a full electric fan install. a dual fan set up.. also considering a oil cooler system.

@Goran124

 

[Goran124]

I am looking for ways to run cooler on my C36 with same M104 engine as your E36.

Did you install 71 degree thermostat?

also, how and where did you install 1 kilo ohm resistor on the temperature sensor?

thank you.

ps. im considering a full electric fan install. a dual fan set up.. also considering a oil cooler system.

@Goran124

Check this video:

 

[gsxr]

TLDR TLDW:

• Replace the stock M104 thermostat which opens at ±87°C and is fully open at 102°C, with one that opens at ±72°C and should be fully open at 90°C.
• Replace the fan clutch with OE/OEM Sachs
• Add the resistor to trigger the electric fans at a lower temp

As an FYI, I find the noise of the twin electric fans on high speed to be unacceptable for "normal" driving.

 

[yao500e]

Check this video:

appreciate it. thank you.

 

[yao500e]

TLDR TLDW:

• Replace the stock M104 thermostat which opens at ±87°C and is fully open at 102°C, with one that opens at ±72°C and should be fully open at 90°C.
• Replace the fan clutch with OE/OEM Sachs
• Add the resistor to trigger the electric fans at a lower temp

As an FYI, I find the noise of the twin electric fans on high speed to be unacceptable for "normal" driving.

awesome. thank you for listing out the steps. it seems that if engine temps can stay 100 degrees or below in hot weather, especially stop and go traffic, that is ideal.

 

[Jlaa]

awesome. thank you for listing out the steps. it seems that if engine temps can stay 100 degrees or below in hot weather, especially stop and go traffic, that is ideal.

Here are the resistance values to use. I archived this from K6JRF's page when I found out that he is no longer with us anymore?
Anyways, my cooling system is up to spec and my electric fans operate at both low and high speed --- but the engine creeps towards 100C when I have no air flow (like 5mph operation) going up steep hills for many blocks at a time in hotter weather.

I put my Cool Harness back on my 500E (CH-92) just to see if I still dislike it (I took it off many moons ago when I decided that I didn't like the noise.). That said, I have not driven my 500E since re-installing the CH-92 so I can't say......

I did notice, though, with my w220 S350 w/ electric fan, that the electric fans run at high speed quite frequently here in SoCal. I will sit idling in traffic and watch the engine temps go down from 95C back down to 85C with regularity. Its refreshing to see that the temp needle go up and down so frequently --- because it gives me confidence that MB considered such temperatures to be normal.

Anyways, I did notice with the w220 that you actually cannot hear the fans from inside the car because the car is so well insulated. I guess that's the problem with the w124 --- not enough insulation.

 

[yao500e]

Here are the resistance values to use. I archived this from K6JRF's page when I found out that he is no longer with us anymore?
Anyways, my cooling system is up to spec and my electric fans operate at both low and high speed --- but the engine creeps towards 100C when I have no air flow (like 5mph operation) going up steep hills for many blocks at a time in hotter weather.

I put my Cool Harness back on my 500E (CH-92) just to see if I still dislike it (I took it off many moons ago when I decided that I didn't like the noise.). That said, I have not driven my 500E since re-installing the CH-92 so I can't say......

I did notice, though, with my w220 S350 w/ electric fan, that the electric fans run at high speed quite frequently here in SoCal. I will sit idling in traffic and watch the engine temps go down from 95C back down to 85C with regularity. Its refreshing to see that the temp needle go up and down so frequently --- because it gives me confidence that MB considered such temperatures to be normal.

Anyways, I did notice with the w220 that you actually cannot hear the fans from inside the car because the car is so well insulated. I guess that's the problem with the w124 --- not enough insulation.

wonderful information.
It does seem benz electric fans work well in stop and go traffic? fans are cooling and spinning during slow speeds?

 

[gerryvz]

Here are the resistance values to use. I archived this from K6JRF's page when I found out that he is no longer with us anymore?

As far as I know, his web site is still up and available, no?

K6JRF Auto Page

My Mercedes S500 Coupe

www.k6jrf.com

 

[gsxr]

I recall K6JRF had a stroke a few years ago, but is he now no longer with us...?

 

[Jlaa]

I recall K6JRF had a stroke a few years ago, but is he now no longer with us...?

Ah, maybe I misremembered. Stroke … ugghhh

 

[gerryvz]

Fake news, I guess….

 

[frankriedel]

Guys

Thank you for sharing your experience and suggestions. I'm looking to upgrade my cooling system to become more robust due to several niggling technical failures of different sort.

Background:

- on my 1997 S500 I had the problem that the high-speed function for both fans didn't work so as a short-cut I bridged the wiring from one fan to another to get max cooling. it was not pretty but it worked until recently; when it completely failed and I got overheating problems...

- next issue which came up was that at higher raving (3.500 to 4,000rpm) all the lights in the dashboard go off and only remedy was to go into neutral, let it drop to idle and the light/limp mode will go off, re-engage drive but match the rpm before so can continue driving.

- initially I thought that it was a gearbox problem so I did a complete engine & gearbox swap from this 187k kms to 27k kms s500 of mine, including swapping the fan controller after I finally found the location -- and both fans worked just fine without "extra cabling".

this all lasted maybe 3-weeks and after that again, I only had 1 fan running; bridge it and both did their job.

- Next thing what went bust was the alternator -- I changed the voltage regulator, but it worked for a few hours and next day I got stranded because of empty battery.

swapped alternator from old engine to new one, lasted a day and same problem.

I also looked at the TCU wiring and indeed there was some oil in the old module but with the new one, gearbox ran as smooth as we all know.

after further investigations, MAIN problem as follows:

- voltage spikes which kill the fan controller (and two alternators).
- I put in a brand new replacement unit and voltage/charging is fine.

Yesterday as staring the car and setting off from parking, car experienced a "hick-up", lights briefly cam on but went out and driving etc. was all normal... until I reached my destination and saw water temp 120C -- caused by both fans not working; inspection this morning -- fan control unit fried again (I bridged at the plug and both fans are working) new unit is on back-order.

Now to come to the point of cooling system upgrades, as I'm living in a hot climate country, I'm looking at a proper upgrade not to torture my engines any further and I asked for advise on the replacement of the manual clutch vs the w220 system, what and how to wire it into the w140 and/or 124 system plus possibly upgrade to additional engine & gearbox oil coolers.

appreciate your efforts and advise

 

[gsxr]

@frankriedel, if your S500 was cooling properly with the electric fans on high speed (keeping engine temps near 100°C), you have an airflow problem... which means the viscous fan clutch is not engaging correctly. Inspect/replace the fan clutch. Running the electric fans on high all the time is a Band-Aid which is not solving the underlying problem. Adding additional oil/gearbox coolers should absolutely NOT be needed.

If the engine still runs too warm (>105°C) with the electric fans on high all the time, you have other problems that need to be identified and fixed. For starters, remove the radiator and blow out the core/fins with compressed air, from back to front. Same with the condenser. If airflow is restricted though either component, cooling ability will be reduced. It's also possible an old/original radiator may need replacement (new OE/OEM Behr preferred). If your thermostat is 10+ years old, replace that as well (OE/OEM only).

Welcome to the forum!