There's several lower temp t-stats available. Just find one that will keep your car at a good temp. A warning though: don't get one that will keep your temp too low or your car may run too rich and may not be able to completely warm up. Ex: I run the 79c in my w201 during summer because the daily temps are around 105f - 110f, so the 79c in conjunction with the massive 600 watt cooling fan keeps my car at about 80c -83c. If I ran the same 79c during cooler months my car would run rich and never really get to operating temp.

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1990 190E 3.0L

First, I would add a bottle of Redline Water Wetter to the coolant system (or more, depending on Redline's recommendations). I used this on my 300D and it does help (even though it might seem gimmicky). It's inexpensive and can't hurt.

Second, you might want to make sure none of your brakes are dragging (including the parking brake). Jack each wheel and make srue it spins freely by hand.

Finally, as others mentioned, are you sure this isn't normal? Gauges on older cars tended to be more accurate and show fluctuations in temperature, while gauges on newer cars are stable by design (becasue the average person go nervous about a moving temperature gauge). If you live in a very hot climate, this could be normal. But I would double check the sensor and install an independant gauge to verify the temperature before I spent any more large sums of $$ on the issue.

Good luck.

It is relatively easy to diagnose an overheating problem.
It is either insufficient water flow or insufficient cooling in the radiator.

You have to check the temperature of the water going in and coming out of the radiator.

If the engine is overheating and the water coming out of the radiator is conservable cooler than the water going in the water flow is restricted.

There are several possible causes:

• Worn water pump
• Blocked thermostat
• Blocked water channels in engine.

If the temperature of water going in and coming out of the radiator are not much different the airflow is blocked.

• A possible (probable) cause is a worn radiator is worn. Over time the airflow gets restricted and aluminium slats come loose.
• It is also possible that a worn airco condensor blocks the airflow.
• The fan only has effect at low speeds, if it only overheats when standing still or driving at low speeds is can be the fan.

The easiest way to check te temperature is with a infrared thermometer, they are not expensive.

Rob