2 questions
 

Should I buy a scan gauge for monitoring temps with using a grill block?

Is the general consensus that a grill block is for aero/streamling, or for just keeping air from entering the engine bay?

Seems that an exterior block would streamline/contain air while a block (behind the grill) would just block.

Or something similar.
Especially in hot weather it's good to keep an eye on the coolant temp.


It's doing both.
It streamlines the front by keeping more of the air out of the engine bay where it causes drag and cools the engine bay.

The air usually goes out of the engine bay through the wheel arcs or underneath the car, neither of which is good for aero.
More cold air means the engine runs cooler or takes longer to warm up, again, neither is good.

Yes. Modern temperature gauges are glorified "idiot lights". That is, they generally go to "normal" and just stay there. The Scanguage shows true temperature and a whole lot more. It helps you to figure out just how much of the grill you can block for outside temperatures and long hills. Grill block helps with aero and quicker warmup, both good things.

Indeed.
The temp indicator on my car doesn't move from its normal position wether the coolant is 78 or 88 °C.

What kind of car is it? Specifically, what model year? Cars before 1996 will most likely not work with the ScanGauge at all. :(

If your car is OBD-2 compliant, the the SG is a good idea. You can set up gauges on it for instantaneous MPG, trip MPG, and load value in addition to the coolant temp one. Those can help you change your driving to give you even better economy...

-soD

i would get some way of reading coolant temps. A SG is nice and will help with MPG in other ways.

Look here for grill block info:
Grill block partial or full - EcoModder

My current grill block is just for heat retention, but I'm planning on making a more aero one over the winter. The grill block has definitely helped me keep the engine warmer when DFCO, and helps it warm up quicker. Without the SGII, I wouldn't have a clue whether it was working, good, bad or indifferent. My factory gauge doesn't look any different between about 168F and 213F, shown on the SG. Too me, that's critical information. Below 177F and my computer is still bumping up the idle to warm up the engine and if I was running any hotter on the high end, I'd probably cut back on my grill block (probably will have to in the summer).

In any case, the SGII is important for a lot of other things, including adjusting the nut behind the wheel. I'm always fascinated at how good a tool it is to teach you how to drive more efficiently. Just learning where you need to drive relative to other cars and trucks to enter their disrupted airflow and gain 3-5mpg while still maintaining reasonable following distance is vital information to have. I've had mine about two months and it has almost paid for itself in saved fuel costs.