not much coolant will be lost.
it's not like the whole radiator will drain or anything like that.

'warmer' is always better for fuel economy.
All factors considered..I can't say enough how important it is to be
running up to proper temp.

On 9/7/2015 2:49 PM, Steve Williams wrote:
> Hi,
>
> It seems like I need to replace the thermostat on my 1991 2.1 L
> Westfalia.
>
> It seems straight forward enough, though as Scott pointed out, perhaps
> there will be a problem getting the plastic housing off.  I can deal
> with that...
>
> What is the best way to minimize the coolant loss while I'm replacing
> the thermostat?  I was kind of thinking of putting the back of the van
> up on ramps to get the housing as high as possible to reduce what would
> drain from the radiator?  Does this make sense?  or should I just drain
> the system & start from scratch.
>
> Also, would the engine running "cool" affect the gas mileage?  I know
> there's a temperature sensor (Temp II?) that feeds the coolant
> temperature to the ECU, but have no idea what the threshold is, or even
> what the input to the ECU accomplishes.  I would assume it's kind of
> like a choke on old carborated engines, but not too sure. It seems like
> I've been getting poorer fuel economy with the last 4 or 5 tanks & was
> wondering if there could be a correlation between that & the engine
> running cooler.
>
> Thanks,
> Steve W.
>