Hi Guys

Have recently purchased this car. She has done 140,000 Km todate, automatic, SW. The question is that the heat gauge sometimes in the rush while creaping on the road, goes slighly above the center line of the heat gauge. By center line i mean in between 80-120, there is a marking in between 80-120 it crosses slightly above that, but when the car gets a speed of 80 Km it goes back and stay slighly lower to 80.

The following things have been changed and checked:
- Thermostate & Coolant (Brand New)
- Both the fan are working which are mounted on the front sode of the condensor.

Is it normal for the Merc as the coolant water is not boiling. Any help will be highly appreciated. I ahve always driven BMW whose temp gauges more or less stays in the middle.

 

i hope the water will boil so it won't go beyond 100 degrees anymore.

check the radiator for cold spots.

 

Any suggestions as how to check the raditor with the cold spots. Do you mean we should get the feel from our hands on different locations of the raditor that hot water is being circulated in all parts or pipes of the raditor.

Is there any special way to see. What about if we wait and see the coolant reserviour bottle level going down and up with the thermostate opening and closing. I think that will be an indicator of coolant being circulated properly in the raditor.
Any help in this regards will be appreciated. I want to keep this car as the driving pleasure of this make and model is very nice

 

but you said you already replace the thermostat.

yes, feel on different area. heat should be evenly distributed.

if all spots are cold and lower hose is not hot, then thermostat is faulty. circulation problem.

if only some spot, it's radiator.

if all hot, ventillation... fan, etc.

 

Keeping Germany extreme tempratures, I though of washing the inner side of the raditor fins and the outer side of the condensor (AC) with a service station water gun. This trick played like a magic. Now the heat gauge remains slightly down from the half marking. Wheras wheni switch over the AC and as the two AC condensor fans gets activated so the temprature furthers drops and it stay slightly above then AC.

I personally think that the raditor fins were completely clogged and the moment the mud and the dirt was washed out the temprature droped down.

Secondly i want to ask that the clutch fan should start as and when the engine is started in the morning. And is this fan have got two speeds like my previous BMW 530i 1995 model was having it. The clutch fan speed use to increase as and when the temp use to rise. I think Merc with 1995 e320 model might be having the same system.

Last of all i want to ask now when the heat gauge stays slightly below the middle,(After 80 on the marking) is it ok or i need to get it checked by somone.
Thanking you in advance

 

I want to ask that the clutch fan should start as and when the engine is started in the morning. And is this viscious fan have two speeds ? like my previous BMW 530i 1995 model was having it. The clutch fan speed use to increase as and when the temp use to rise. I think Merc with 1995 e320 model might be having the same system. Is there any relay which kick back the viscious fan with the second speed so that the temprature gauge remains sligtly above 85 and below the first marking?

Last of all i want to ask now when the heat gauge stays slightly below the middle,(After 80 on the marking) is it ok or i need to get it checked by somone.
Thanking you in advance