How to block your grill

I used the 3/8" pipe insulation, bought it from ACO for $1.19 for a 6 foot or so section.

I halfed the pipe insulation. Then I stuck those in the grille.

On my own preference, I left the drivers side of the grill open about 6" just go get some air in there. You dont have to do this, though. Some leave it completely blocked.

Once you get the pipe insulation and cut it, you'll see exactly 2 ways it can fit. I took the half piece and folded it, then wedged it between the slats. Some dont fold it and just push it in the slat.

 

i used 1/2" on my gen II. cut it to length and slid the split over the horizontzl fin, 1/2 above and 1/2 below. also have to make verticle slices for the verticle fins.

 

I used the same size as biscotti but I squeezed 1 whole piece into each slot.

 

Cool! It does make a big difference, I noticed right away with my mpg's. The only problem I had was if I go on a highway trip longer than 1 hour in duration, my ICE was getting too hot (204f) with the lower grille 90% blocked and the top 100% - even though I was leaving the drivers side of the grill unblocked 6". I took one whole piece out of the middle of the lower grille to allow for more air to pass through the radiator and as soon as I did my ICE temps dropped to 185f.

Oh, nobody else has mentioned it yet but a Scangauge II or the Torque app on your smart phone coupled with a bluetooth OBD2 connector are GREAT ways to monitor your Prius and to squeeze the most mpgs out of it.

 

When you are grille blocking how hot do you have your heat running? I usually set my temperature to 76 to 78 to pull some heat out of the ICE.

 

I generally put my heat on "AUTO" and turn the A/C off. When the car is fully warmed up I set the heat to like 70-71-72 usually.

 

I'm just thinking if you're worried about grille blocking and the ICE overheating, you can turn your heat up inside the cabin to pull some of the excess heat out of the ICE. Remember there is essentially two radiators in the car, one is at the front of the engine compartment used for engine cooling, the second one is smaller and used for heating the air going to the cabin. That’s why when a car begins to overheat you can cool the engine down by turning the heat on full blast.

I have a long commute going to work so I run my heat continuously at 76 degrees or higher when driving those long distances. It's nice to have heat during the super cold winter mornings.