This may be a dumb observation, but has your thermostat bypass bleeder
valve been left open? Are the hoses a stock configuration for the automatic?

Jim

On Thu, Jan 24, 2013 at 11:26 AM, Craig Cowan <phishman068@gmail.com> wrote:

> Hello Gang!
> My '90 GL (Automatic) is giving me troubles. Some may recall this van had
> sat for a few years before I came to own it, and I have turned it around to
> a reliable  daily driver. Anyway.... It's time to throw more work into it.
>
> I had previously had a problem with the temp gauge never rising above 1/3
> on the gauge and it wouldn't make good heat. Of course I had a bad dash
> blower, so wasn't all that sure on the heat.
> Gas mileage was always bad. 14mpg max.
> Well last weekend I finally replaced the thermostat and things were looking
> good! The temp gauge would now read right in the middle, and with the new
> dash blower as well, i now had heat!
> But surprisingly, the gas mileage suffered still.
> Yesterday I filled up and found I had gotten 10.5mpg on that tank.
>
> Today I did some highway driving. This bus runs like a champ! Seriously
> good power, however I now see that the temp gauge will drop all the way to
> the bottom if I cruise at anything above 60mph. Anything below 50mph will
> maintain the temp gauge right in the middle, where it should be.
> I've never seen this happen. Any ideas?
>
> I believe this weird temperature problem could account in part for my
> terrible gas mileage. I recognize that I shouldn't quite be expecting
> 20mpg, but 17 would be a reasonable thing to find from an auto bus in my
> experience. There are a few even in my area that do get 20mpg, easily.
>
> Any thoughts?
>
> -Craig
> '90GL
> '87 SUNROOF SYNCRO WESTY ZETEC
> '85 Barn
>