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Discussion Starter #1
Hello guys. There is something i dont get it with my W210 E230 1996. when engine temperature in low or in its range (up to 80 degrees celcius), the car acceleration is perfect. when temperature gets high a bit, the acceleration is badly affected. and when temperature gets high, say 95 degrees, i fee that the car struggles to accelerate and even didn't accelerate on ramps.

any suggestion abt the reason?
 

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It is simple Automotive Technology 101 as they say......

A) Then you need to add this resistor to the "four-pin" temperature sensor?

https://www.k6jrf.com/MB_S500.html#MYCH

B) 96-97 W210's have a clutch fan on the engine, but 98-2002 W210's do not have a clutch fan, but have an inside electric fan that works effectively. I would get one from a later W210... Turn on a relay from the front fans that will turn on the inside fan..

Going to a 722.6 from a 722.4 will help too read your other thread you started... :thumbsup: :D

Martin
 

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Discussion Starter #3
Thanks Martin for your reply. I really liked that resistor idea. do you have an idea the value of the resistance how much it is?.
for the second choice, it is a good choice & was thinking about it too. but got some hesitation to change & add relays and be exposed to maintenance problems later. But in case no other solution, i might go for it.
 

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You can read the specific solution proposed below.

https://www.k6jrf.com/MB_CTS.html

BTW, I am not even sure if this will work for you. I suspect that your coolant temp sensor is a two-wire (one sensor only) device. But I may be wrong.

But, to see if this solution is actually going to help you, you can let the aux fans to turn at max speed, if you keep pressing BOTH AUTO buttons for 10 seconds when you have the problem. That is, if you have the non-tempmatic climate control unit.

Make sure that the radiator and the a/c condenser are clean of any debris and crud.
 

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Hello mrboca. Actually I have the same sensor shown in Cool Harness V2. I am curious to know the resistor value. I think i can do the soldering myself.

Unfortunately, I mixed the coolant liquid with some tap water which i shouldn't do. I will remove it all, clean the network & fill it with genuine coolant liquid.
In addition to this, I think i need to have also a similar solution to the Cool Harness V2 since the weather here in saudi Arabia is wayyy hot.

how can we know the resistor value?
 

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It tells you in the link I posted. If you want the A/F to run at 95 degrees C use 1200 Ohms wire resistor (not carbon).

Use water wetter or Purple ice products to reduce coolant temps. Use less antifreeze and more distilled water in the coolant. (40/60 for example). Water is much better in removing heat.

As I said, make sure that it is the raised coolant temperature that causes your problem.
 

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Discussion Starter #7
in my case the A/F starts to work at 80 degrees & believe it in the hot hot weather here in KSA, the engine temperature gets high and i started to lose engine power. I am planning to have the fan running below the 80 degrees, say 75 degrees. so the same resistor is gonna be used?
 

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If you are into electronics, you should be able to get a curve for the coolant temp sensor for the A/F, and plot the resistance value at 100 degrees C (first stage), then plot the resistance value for the 75 degrees C the temp that you want the fans to start. Then calculate the resistance value you need in parallel, to give you the effective resistance value at 75 degrees C.

1/R75 = 1/R100 + 1/Rx

1/Rx = 1/R75 - 1/R100

1/Rx = (R100 - R75) / R75 * R100

Rx = R75 * R100 / (R75 - R100)

Assuming a linear relationship : If R75 is 400 and R100 is 300, Rx is 1,200 Ohms.

If you claim your A/F starts turning at 80, then you need R80 value in the graph, instead of R100 on the curve.


Then again, I believe you are barking the wrong tree.
 

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Discussion Starter #9
Well, i need to say that this is impressing. Thanks for this interesting step by step calculation & explanation. Whats going on exactly with me is when i start the car at morning & the engine temperature is still low (even below 70), the car acceleration is something amazing. when temperature reaches 80, the acceleration goes down a little bit but it is still acceptable. if i use the car & don't load it & even in 45 degrees Celsius ambient temperature, engine temperature remains 80 & engine power looks okay. loading on the engine & accelerating for 1 or two times only ==> engine temperature QUICKLY and quickly gets high about 95 and at this stage i loose much of engine power.
I think that the engine temperature shouldn't increase that quickly through accelerating for a period that can be considered short.
Here comes what i was thinking of: use this resistor mounted in parallel so when i accelerate the temperature, after getting high because of the acceleration, will be in the range of 85 and thus the engine power will be higher at this stage.

i hope i made it clear.
 

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Assuming your engine has proper tune-up, sounds like your radiator has accumulation of boiling stone and cooling efficiency suffer.
I drive my diesels in 45-50C and in gentle driving engine can stay below 80C.
Making the fan coming quicker will make short-lived band-aid.
It will help for few seconds, but not real solution.
Start with monitoring the real engine temperature on climatronic, or scanner as dash gauge is not showing small temp changes.
 

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I think the resistor is a band aid solution. Think about it. The aux fans are supposed to start at 100 degrees C (at least in the link above). The engine should run just fine at 95 degrees C even though it is at the high end for coolant temp.

When did you last service your cooling system ? You indicated you used tap water and coolant, which is a NO. Did you flush the cooling system with radiator flush such as citric acid ? Have you replaced the thermostat ? What about the water pump ?

There are many factors that can cause a rapid coolant temperature rise. It could be a worn out water pump, sticking thermostat, clogged radiator or coolant lines. etc. Also remember that the coolant temperature sensor shows the temperature of the coolant which is less that the hot spots within the engine. You may have head gasket leakage issues. Who knows.

It may be something to do with the air to fuel ratio, as the engine runs rich when you have a cold start, and it is not monitored and controlled with MAF, O2 sensor, ECU etc, till the engine gets warmed up. If you have a problem with any of those, the engine will be sluggish.
 

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Discussion Starter #12
- Water pump is replaced
- Thermostat is replaced
- Air mass sensor is replaced too.
- even the fuel pump is replaced. what i thought at the beginning that maybe because of the temperature & heat the fuel pump efficiency was getting decreased. i didn't notice a difference after change actually! :(
- Radiator: I didn't flush it & i used genuine coolant liquid mixed with tap water which i guess i shouldn't do. I will try to flush the radiator & use only genuine coolant liquid.
- I was thinking of how measuring the efficiency of the engine & the gearbox. would you think it may help?
 

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If you are recording decent mpg, that is easiest engine efficiency test.
Bad tune-up will always show in high fuel consumption.
Checking radiator efficiency is pretty hard on other hand and you have to eliminate other problems to judge it bad.
Still your main concern is lousy performance, what should not happen with engine even at 95C.
So again, observe temperature with real gauge.
Than I don't see it mentioned, but did you check for codes? Is your car OBD equipped?
 

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- Water pump is replaced
- Thermostat is replaced
- Air mass sensor is replaced too.
- even the fuel pump is replaced. what i thought at the beginning that maybe because of the temperature & heat the fuel pump efficiency was getting decreased. i didn't notice a difference after change actually! :(
- Radiator: I didn't flush it & i used genuine coolant liquid mixed with tap water which i guess i shouldn't do. I will try to flush the radiator & use only genuine coolant liquid.
- I was thinking of how measuring the efficiency of the engine & the gearbox. would you think it may help?

Have you changed the fuel filter and the fuel regulator ? A leaking regulator will not meet the pressure demand when you are accelerating, and your engine will run lean after it gets hot. And a leaner running engine will run hotter.
 

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Discussion Starter #18
If you are recording decent mpg, that is easiest engine efficiency test.
Bad tune-up will always show in high fuel consumption.
Checking radiator efficiency is pretty hard on other hand and you have to eliminate other problems to judge it bad.
Still your main concern is lousy performance, what should not happen with engine even at 95C.
So again, observe temperature with real gauge.
Than I don't see it mentioned, but did you check for codes? Is your car OBD equipped?
What i will do is to check the fuel regulator (fuel filter was changed less than a year ago), will flush the radiator & the cooling system network also & fill it with genuine coolant liquid. I will post the updates here.

observing temperature with a real gauge: i changed the temp sensor and it is giving very similar reading to the old one.
OBD: i have no idea, will check if the car can be plugged to OBD scanner.
 

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Discussion Starter #19
Have you changed the fuel filter and the fuel regulator ? A leaking regulator will not meet the pressure demand when you are accelerating, and your engine will run lean after it gets hot. And a leaner running engine will run hotter.
Actually no, I will check it too.
 
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Abdel Karim Baarini
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