Is Cooler Better
 

Is running the car a bit cooler than normal temp better or is it not good for it?

I am talking 80C is the norm and 65C to 75C is what it runs at.

What are the pros. and cons? If any.

Thanks

Thats way too low. Are you sure your temperature gauge is right?Engine wear increases significantly at temperatures 75 C and lower. I would suggest that you change your thermostat.

i would agree, it sounds like your stat my be stuck open....does it take a long time to reach full temp?

I used 90 degree thermostat on my 400E this winter, my acutal coolant temperature was 100 degree, I then switched to OEM 80 degree thermostat since this February, my coolant temperature has been 90 degree since then.

Right after I switched thermostat, with 10 degree difference, I did notice slightly more power but my fuel economy got worse, from 14L/100km to 15L/100km, that was with winter gas though, in summer time I get much better than that.

My view on this (and its only mine!) us that the engines were made to run with a 100 degrees stat in them, any variance from that causes problems.

I am pretty sure it sounds like your thermostat has failed... constantly running the coolant through the radiator.

The coolant temp setting for open/close (usually 87 d) is the "optimal" temperature for the engine. Running it at a much lower temperature can lead to ineffeciency and premature wear.

The part is 10 bucks... cheap fix!

Thanks to all who replied
 

I just want to thank all of you who replied.

I know that my stat is bad. And I have purchased a new one to put R&R already, I was merely curious.

The stat was a cheep fix but not 10, my stat is $47

$47 ????
 

I got my OEM thermostat from Partshop here for only $21, I think my 400E uses the same thermostat as your W140's.

Re: Thanks to all who replied
 

Still much cheaper than an engine rebuild.

Definitely no two ways about it Sir.