Seems to be much controversey on this one. So it's getting up to 20 degree's celcius in Ontario these days - but still doing down to 5-6 at night, and sometimes only as high as 10 degrees. Should I block? I havn't yet - just got the Prius, should I now wait until next winter to start? When do other Ontarian's block/unblock their grills?
Generally, 15°C is a good marker if you don't have a scangauge. You can push to 20°C but only in city driving (no highway or heavy load driving). I remove mine when the temps go > 15°C
You can also partially block or have more of your grids blocked when it's colder (mornings or days when it's colder). I've been moving the bottom grill blocks in/out the last week as temperatures been getting warmer in general.
I removed the upper on Pearl yesterday but left in the lower for now. I DO have a Scangauge II. It was 20C yesterday. Coolant ran at 85C on the highway. Unless I'm mistaken, the inverter coolant circuit cools from the upper mostly, which is why I removed it first. I'd not bother with blocking until the fall, in your case. Also, I recommend getting a Scangauge II. They're not very expensive, and are quite informative. And it takes the guessing out of the grill blocking.
I keep the upper grill blocked all year. The lower is 4/5 blocked. The middle is open. I'll remove the bottom insulation when the fan starts. There have been a few afternoons that have reached 80F but the fan hasn't run. I've also lowered the windows and turned off the AC.
I just bought a Prius. I live in Vermont - ie. COLD. Sounds like I will want to block the grill next winter. Tell me, how do you go about blocking the grill?
So far yes. I've been removing two insulations slits from the bottom grill when it is warmer. The mornings have been pretty chilly so I've putting them back in then. Also if I go on a long HWY trip I usually stop and remove one or two slits.
Congrats on your new Prius. If you do a search on grill blocking you can find a number of threads some even have pictures. Also look on the bottom of the page for this thread and see "similar threads". Click on any one of these and review the info. In general a lot of us stuff pipe insulation in the grill slots. let me know if you have trouble with your research.
