blacksnapon said:

If you modify things with a tuner, some things will work, others wont (it all depends on what perameters they change). I'm just going on stock configurations. The electronic cooling fans wont even come on until 214-225 degrees. Some vehicles rely on the water temperature to be 195 for the pcm to adjust air fuel mixtures, some rely on oil temp for the major adjustments. With the engines being more "sealed up" today, for emissions, they rely more on engine heat for burning off the harmful contaminates. Yes, the 50-60-70-and some 80s engines, had much more leeway in the temperature variances, not today.

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Bob Ayers said:

And MPG for Cafe standards!

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Bob Ayers said:

Exactly right Vince!! The mechanical fan on gasoline Mercedes (from early 90's) is engauged with an electric clutch, and it doesn't engauge until 100C (212F). As far as the PCM going into closed loop mode, I'm not sure if it relies on a timer (waiting so many minutes after a cold start), or it watches the ECT sensor to reach a MIN temp. I know the PCM will throw a code if the MIN temp isn't reached within a specified time.

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eco said:

I don't know about Mercedes (they are irrelevant anyways) but the Ford EEC-IV can easily be reprogrammed to work around a 180* t-stat to reach closed loop and the fuel tables to match. This way you get the best of both worlds. Also, as far as the fan, if it's mechanical then there is nothing to worry about there, if it's an e-fan (your all time favorite mod) then the installer can engineer it to work however they want - so no problem there either.

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eco said:

Cafe standards??? What is that???

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Bob Ayers said:

And, why would somebody install a 180* thermostat?

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eco said:

To get the better performance that a cooler t-stat has to offer without going cool enough to increase wear. Tune the computer for it of course. Why else??

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Bob Ayers said:

I guess you missed the posts that Vince and I posted about the higher temps (195) boiling off the contaminants in the oil quicker for reduced wear.......And more contaminants
will be created due to the PCM running the engine richer at the cooler temps.......And reduced MPG..........

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