Thanks Jim
One more question, wich one is the temp. sensor? I got two sensors going in verticaly into the termostat casing. They look almost identicle.

__________________
Dmitry
90' 300CE
17" Intra Signums
Brulen mufler
Euro Headlights/Clear Blinkers
White gouges (made my own)

It's the "FAT" one and has a black cap (probably). Pull off the top and it has four terminals.

By the way, each section should track one another.

__________________
Regards . . . . JimF
-------------------
'94 S500 Cpe

Visit my Mercedes Web Page

Jim F.,
Do you have the resistance for aux. fan cut-in ?
[above 100c]
Thanks
Arthur

This is a corollary to what's going on here but not directly related.

Saw a post re the use of a wetting agent to lower the operating engine temperature. Product is called "Water Wetter" by Red Line Oil. This is the first that I've heard of it so I gave it a try. Check out this direct link: http://www.redlineoil.com/redlineoil/wwti.htm

My engine temp runs around 90 - 92 deg C when warm (ambient temp around 65 deg F) in driving in stop/go traffic. Also "estimate" that the mix was more like 60% antifreeze/40% water.

Replaced some of the antifreeze by siphoning off about a 1 gallon so mix was about 30%/60%. Then added 1-1/2 cans of Water Wetter introduced into the small overflow tube after removing the fluid from the overflow reservoir.

Lowered temp to around 83-85 deg C using same conditions as above.

Some words from Water Wetter site:
COOLANT EFFECTS ON PERFORMANCE
Under moderate load conditions, each percent glycol raises cylinder head temperatures by 1°F. 50% glycol raises head temperatures by 45°F. This increase in temperature will raise the octane required for trace knock levels by typically 3.5 octane numbers. A car equipped with a knock sensor will retard the timing to compensate for the increase in octane requirement by approximately 5°, which will reduce the maximum brake torque by about 2.1%.

I'm impressed with the stuff!


[Edited by JimF on 04-04-2001 at 02:16 PM]

__________________
Regards . . . . JimF
-------------------
'94 S500 Cpe

Visit my Mercedes Web Page

Arthur,

That's my next project. Want to lower the temp at which the fans (two on my car) cut in. Have seen that the fans are set to cut in around 100 deg C. I personally think that that's too high; sb more like 90 deg C but 95 deg C tops in my book.

When I find out how-to-do-it, it'll be posted!

__________________
Regards . . . . JimF
-------------------
'94 S500 Cpe

Visit my Mercedes Web Page

Jom,
That would be great.
I have wired just about every aux fan on my previous
Benz's, but ran them with manual switching.
Nice to have that option.
Let me know what you find.
Many Thanks
Arthur

Tested the T sensor this weekend by stikcing it in hot water (right after boiling). Looked like the gauge was ok.
Than on Tuesday I went to the tech. We did it together. Reading the gauge and lazer termometer. His reading was 75 C
when he pointed on the Temp sensor casing and on the part of the waterpump where the sensor goes in. The gauge read 95 C. What the hell..... Can a Benz run below 80 C ?!?!
In any case, summer is coming, any news on lowering that cut in tempreture for aux fans.
This is what I know on cut in T for fans (on W124):
Viscous fan clutch 96-104 C
Electrick aux fan on 107 C of 100C

__________________
Dmitry
90' 300CE
17" Intra Signums
Brulen mufler
Euro Headlights/Clear Blinkers
White gouges (made my own)

Dmitry, sounds like your coolant sensor and gauge are certainly out of whack! Actually, it's a good idea for everyone to occasionally check gauge accuracy since these meter movement mechanisms can easily go 'off' with time. Below is my procedure for calibrating the coolant temperature gauge and sensor. The specific locations and values apply to a W124 with a 103 engine. Since you probably have the first year of the 104 engine on your 300CE you may need to adapt them to your particular engine.

1) locate the coolant temperature gauge sensor. There are several engine temperature sensors so be sure to get the correct one. On the 103 engine it is located on the cylinder head, second sensor from the rear and has a single-pole connector. You can verify the correct sensor by pulling the connector when the engine has warmed up - the gauge display will drop out of range on the low side.

2) measure resistance at the sensor when the engine reaches operating temperature. For example, on a 124/103 the resistance will be 63 ohms (+/- 2) at an operating temperature of 80C IF the gauge is accurate and the sensor is good. If you want to measure resistance at a different temperature or if the sensor is different on the 124/104 then let me know and I'll calculate the appropriate values for you. (Btw, I suspect that the resistance value posted by JimF are for one of the other sensors?)

3) if your gauge shows a large discrepancy between sensor resistance and the ideal value you will need to either reset the meter pointer or at least make a mental adjustment. (It's possible that you inadvertently stretched the pointer when you were working on your instrument gauges.)

Hope this helps,
Barrie
-----------------
'86 300E

My display comes on and displays a temp for about 10-15 seconds and then goes off. The display is on about as long as the set belt warning, just a little longer. It seems like it is working correctly however it is using c and it takes a greater temp to change. If I can not get it to work can I just turn off the light on the display?

Barrie,

Just to confirm that temp chart was for my S500's ECT sensor. You are correct in that temperature measurement for your car (W124 with a 103 engine) is different.

The S class cars have two coolant sensors; an ECT (B11/2) and CT sensor (B10/8). The latter sensor controls the A/C and the auxillary fans. The ECT sensor's output is what is read on the temperature gauge in the instrument cluster for S cars.

The chart values was for the ECT sensor which is completely different for the CT sensor. A bit confusing!

__________________
Regards . . . . JimF
-------------------
'94 S500 Cpe

Visit my Mercedes Web Page

Since Dmitry's problem is with a '90 300CE he should use the relevant procedure and values as provided for the W124.

Where can I get the values for my car?

__________________
Dmitry
90' 300CE
17" Intra Signums
Brulen mufler
Euro Headlights/Clear Blinkers
White gouges (made my own)

Dmitry,
Except for the difference in sensor location on the 104 engine vs the 103, I believe the temp gauge system is the same on your car as any other 124. You should be able to use the procedure and values that I provided above to locate, test, and calibrate engine temperature with your instrument gauge.
Be sure to locate the correct sensor for your purpose - you do NOT want the sensors that control the fuel system or fans (B10/11/12). There is a *separate* sensor for the gauge (B13). Btw, I suspect S-Class and others of the same vintage use the same system (and probably the same values), but I have not checked that.

Barrie