Thermostats

[Yurick]

Hi everybody!
What are the advantages and disadvantages of installing a 71 or 75 degree thermostat in place of the factory 80 degrees one on a 1990 325iC?

Thanks!

[Bear]

I am driving the exact car with a low temp thermostat and the only thing I see is less heat from the car heater in cold weather. The needle on the temp gauge never reaches half way as well.

[Josh at Pelican Parts]

Hey Guys,
The advantages of a higher temperature thermostat are:
Optimized engine running temp for proper fuel economy, lower emissions, and better heat output during winter. Additionally, a higher degree thermostat allows the liquid in the radiator to drop further in temp, providing superior cooling to the block/head upon its return. I know it may sound counter-intuitive, but it's true. Using a lower thermostat may maintain a more even temp overall, but once open, it pretty much stays open. This condition allows the water to circulate without the proper valving. On a very hot day, it's a recipe for a boil-over. Over time, this leads to premature head gasket failure and can affect idle control.
This goes for any modern car with computer controlled fuel injection and system monitoring.
The days of removing a theromstat for "better cooling" went out with the carburetor.

[Bear]

Wayne, I totally agree and also if the stat is too low in temp it will hinder operation of some emission control devices. The days of the 160 degree stat should be over (at least for street cars).