2010 Prius Grill Blocking strategy

Brrr! You could use some more grill block! As Maarten mentioned, the car wants to run at 195F.

I haven't been up Mount Seymour, so don't know just how steep (for engine heat) and slow (reduced airflow) that particular road is. It is definitely worth monitoring the temperature anytime the grill block is in. But I have never seen mine climb above its desired 195F in winter on any of my hill climbs. Or even spring. One cold summer, I even left half my blocking in until a hill climb in September. (Warning: this was specific to both a mild climate, and a particularly cool year. This would have meant trouble most other places.)

I'd also mention that grill blocking reduces the rock and gravel intake that severely flattened most of the lower radiator fins on a previous car, significantly reducing its cooling capacity. Cars that have already suffered a significant amount of such flattening, will need to remove any grill blocking sooner than I commonly do.

And don't ever leave any grill blocking in as long as I do (past winter), without an OBDII-port engine monitor to watch that coolant temperature.

 

2010 Gen3 I blocked about 75% of the lower grill and was driving in 85F weather. Here is the butt, 7~ miles each way, 60's in morning, 80s afternoon. Got me heat faster and the engine warmed up faster for sure. EV and coasting was so so. Not sure how much it helped MPG. Engine temp never went over 193F as that seems to be where the thermostat opens. In the summer with no blocking I've seen a 205F engine temp or something like that.

I plan to do this earlier when it gets cold. Did it the last few months last time it got cold.

 

I block 100% of lower grill all season long when it comes to stop and go grocery shopping, temps are monitored with hybrid assistant app. Anything major thing like increase of ICE for more than a couple of minutes, it gets fully removed. There are other things that doesn’t have a thermometer that does need cooling though so that’s why I just don’t strictly go by engine coolant temp.

 

Was wondering if anyone has made a custom shutter design into the bumper guard and grill. I have my existing that I'll eventually replace with the new bumper guard and was planning to make a custom bumper guard grill with the original implementing with a shutter and probably not an MCU and more likely a simple circuit with temp sensor(s) to control. I really only see an issue in what I find to be the "55" rule I term the situation. 55 mph or less and 55 degrees or more outside temp, I can still reliably obtain 55 mpg in ECO mode. Of which seems crazy to me with 220K and still achieving. Though wondering since I did the ride and glide as well as granny like EV mode as much as I could accelerating throughout the life I've owned. Early on starting at 20k when I first invested in and in the southwest... I was seeing 65mpg reliably. These engines seem to like the warmer and I'm thinking dryer weather.

Neat to read all these DIY cost effective methods. Zip ties are handy for repairs too, not only for plastic welding rod even though salvage yard pieces cut for are best to match polymers. Same goes with even the clear Duck tape to lower the drag around the zip ties.

 

157K on the clock w/67.1 mpg on last week's tank. 157K is the new 20K

 

FWIW On my '16 RAV4 hybrid I kept the grills (including inverter) covered all year. Even went on a 75MPH 100 mile round trip in 85F weather and never had an over heating problem. For the vast majority of people I'd wager that blocking the lower grill all season probably won't do damage.

If you're paranoid about it then remove it during the summer and watch your temps regularly.

Most engineers oversize the radiator to account for people who may be driving regularly in abnormally hot climates. IMO worrying about a lower block in 90F summer in moderate use is probably a waste of time.

(Slightly resurrecting for new folks who might pop by via the Google)

 

The above might need some “peer review”…

 

fact check?

 

Okay now in fairness I did say "for what it's worth" which is mostly a grain of salt since it's a different car haha

As far as the oversized comment, I'm sticking to that. The radiator would be designed to handle the loads expected of a car across it's varies climates. It would be foolish to assume that by simply blocking the lower grill (which I've also done on my gas engines during summer) you'd suddenly expect over heating due to lack of air flow.

That's not to say you should just up and ignore your vehicle. I kept mine blocked all year because I saw no appreciable load temp difference.

 

I gather the only reason no one is using the HD Duck tape is due to the potential residue and/or affect on paint if and when removed?

I'm going to block my lower grill 100% and 50% of the upper using the HD Duct tape since I have a roll and that stuff holds up very well compared the Gorilla tape.

On another note... using Chrome and maybe Lubuntu 18.04... is there some reason the Facebook, Twitter and Google logins aren't functioning?

 

Foam pipe insulation tubes secured with Velcro tape is what I’m using; very secure, and simple to install/remove. Temps are rarely below freezing here, so I’m just doing 50% of lower. If it stays below freezing I put a second tube on the bottom. Never do the top. Also, if doing something like a (very rare) ski hill climb, I remove all grill block.

 

I use a sheet of vinyl stair tread protector that I just unroll behind the grille. It's less of a fashion statement for passersby; you pretty much can't tell it's there.



I made it first for my Gen 1, further described in this post, and cut holes in the bottom, because that's where Gen 1's electronics radiator is.

I just kept it when I got the Gen 3, and put it in the other way, as Gen 3's electronics radiator is on top.

I've watched the temperatures on a ScanGauge and I probably never even really needed to cut the holes, but I didn't have the ScanGauge at first, and I just didn't want to take chances.

Sometimes I've forgotten to take it out until quite late in the spring, then I eventually look at the ScanGauge and think "oh yeah, should probably take that out".

 

Whatever works, and whatever personal preference is. Personally, I take 1/2" pipe insulation, cut it in half with scissors, then fold that in half, and stick it in the grille. I cut little slits so the insulation can accept the vertical slats in the lower grill, and not look all goofy sticking out.

Starting in December, I block my grills 99%, I say 99% because I do leave about an inch open on the top grill for the inverter loop. I have monitored temps with TechStream and have never even come close to 'running hot', even when on the highway, and on those random Michigan winter days where its 50F degrees out. I do pull the pipe insulation around mid/end April.

 

Decided for the $4 investment... the 1/2" pipe insulation held the tape up better. Was thinking the tape will lower drag too and I do have a new bumper guard to replace the current installed, for when I get into a more crafty experimental fab phase with the existing on the bench.

I have a few hours on the freeway next drive, so will see how performs in regards to temperatures. I didn't block the top grill yet... though thinking will do 50%.

Wondering, like some mentioned they keep their bottom grill covered 100% on the gen3's, how that will perform in the southern Michigan climate year round?

 

Now thinking about before I leave to do a quick local, not so far, drive... after 45 sewing machines rescued... why not plan for a custom bra project with velcro flaps, on the at least upper radiator openings maybe on three sides, so I can just tuck back the flaps behind it for summer or demanding times?

 

Overkill. If you’re using AC, counterproductive.

 

I wound up leaving 100% covered on the bottom and never wound up covering the upper grill to this day. During that region of below 55°F and driving slower than 55mph I still was achieving ~55mpg or better. During the colder periods my guesstimate is a 2-3mpg improvement, though I didn't monitor very critically. No logging and with a nice audit trail.

Anyone know of a free Android app that has an audit trail and/or data logs the OBD2 metrics? I've only been using Hybrid Assistant for the car.

I haven't been monitoring mpg performance throughout the summer since I didn't notice any adverse situations. Was only monitoring temperature until the first few heat waves, where I'm assuming is correct using the Bluetooth OBD2 OBDII Car Diagnostic Scanner Code Reader Check Engine Light for Android and Hybrid Assistant. Being that I didn't notice temp over 205°F driving all day with my AC on sometimes full blast and outdoor temps in the mid to high 90's. Typical temps were 194°F or less.

I just got underneath to see what was rattling and found my exhaust muffler pipe mount, just after the straight section where bends, welds completely broke. I just added two stainless steel zip ties wrapped around the pipe and fished through the two holes on the mount for now until I can either get in to have welded or find the confidence to weld myself. Thinking time to hit the salvage yard up for the equivalent material and practice welding on if going the later route. Should be fun and maybe can plan the pipe to be useful for like other equipment maybe.

I didn't make a video or take photos... was all paranoid working by myself underneath the car (neighbors in the perimeter out though) and having the rear end of the car on ramps.

Anyways, a little TMI tangent, figured I'd post an update seeing I didn't regarding the engine radiator grill block.