grill blocking

First I tried to use the rubber type insulation, but found that it was too soft and had too much friction on the plastic to easily get into the grill. I went back to the store and got the black foam type pipe insulation. This was much easier to get into place. I've had the foam in place for a month and no sign of degradation yet. I've never seen gray foam pipe insulation before.

I got the Frost King foam insulation from Lowe's. Super easy to cut and slide into place. I cut the entire section in half, then folded each half over on itself, cutting a slit where the vertical grill slats go.

 

Warning... I may have caused the "Triangle of Death". Yesterday with one strip of grill block. It happened on I 65 in northern Kentucky. The dash lit up and cruse control quit. It was about 70 degrees. I limped about 25miles to the nearest Toyota dealer. On the way I pulled the grill block off. They read a P0A93 code. It's still an the dealer till a Prius trained tec. checks it tomorrow. I don't think I'll do any more grill blocking without being able to monitor both cooling loops temperature.

 

^ I wouldn't do any amount of grill blocking, once you get above 50~60 degrees Fahrenheit. Basically anytime you might remotely want to use AC for cooling; grill blocking is then completely counterproductive. Also, when grill blocking, you want to know where the inverter coolant radiator is, and avoid blocking that zone.

I'm blocking "conservatively", using the black foam tubing, typically 50% of the larger lower grill on my third gen (inverter rad is behind the upper grill in my case).

It lasts years, doesn't deteriorate. Get's a little squished looking is all. I leave the 4' sections full length and use a Velcro tape strip near each end to secure it.

Once ambient temps are getting above 10C I take it off. Also, if we're doing something like going up a ski hill I'll take all grill block off, no matter the ambient temp.

 

The two cooling loops in your Gen2 Prius are independent:

1. The ICE loop which is pumpedby a standard mechanical coolant pump driven by the "serpentine" belt
2. The "Inverter" loop which cools both the power electronics and the HSD. It is driven by an electric coolant pump

Both loop coolants should be replaced at 100k miles and then every 50k miles thereafter with the pre-mixed Toyota pink SLL coolant. I replaced both pumps at 150k miles and the serpentine belt as preventative maintenance.

My xgauge list shows Engine coolant (both F and C), but no listing for the Inverter coolant for a Gen2 Prius (both exist for a Gen3).
My Torque Pro lists both ICE and Inverter temps.

JeffD

 

I block the upper grill when temperature drops enough that I’m pretty sure that I’m not using A/C until the next summer. Lower grill is blocked 80% when temperature stays colder than +5c/41F (here that means whole winter). In gen 2 inverter coolant loop is on bottom part of radiator so that’s where you should leave the opening.

 

My grill is pretty much blocked all year. Every traction battery is going to eventually fail. Your traction battery may still be under warranty.

I have the 3/8" Frost King in the lower grill secured with twist ties. I use the rubbery pipe insulation up top. Over the last almost 10 years I've lost a couple pieces from the top. I've also lost some of the protective strip covering the adhesive so some pieces have been stuck on the car.

 

Why are you talking about the battery?

P0A93= Inverter Cooling System Performance

Pretty self explanatory, I think.

 

Sorry, my mistake.

 

The P0A93 error was my fault for having the lower 1/3 of the grill blocked at 65 to 70 degrees.
We picked up the Prius yesterday and I drove it home ( 90 miles at 70MPH) with no problem except for a very irate wife.
The dealer charged $114 for testing. Nothing else was found after the code was reset.
The Prius is smarter than I am. No more grill block for me.

 

I'm not sure about '08. With 3rd gen, if you choose front defog button (dedicated button) AC does for sure go on. And if you choose heat/defog mode, sometimes AC goes on.

But the main negative about grill blocking with AC running, for me, is that if you're using AC for the usual, cabin cooling reason, then it's completely counterproductive to grill block. AC works by exhausting excess heat through a big radiator in the front grill. Blocking the grill in that situation is like driving around with a foot on the brake.

 

A/C only cools the evaporator coil to about +1c/33F. So colder it is less the A/C will be cooling the interior and heating the condenser. With my grill blocking it’s still normal that engine is running cold when A/C is on for defrost.

Spoiler: Grill blocking and defrost use

I block the upper grill when I don’t need A/C to cool. And I block the lower grill 80% when temperature stays bellow about +5c/41F. So many times I use A/C with upper grill blocked with defrost when temperature is bellow about 8c. Or use A/C with defrost when upper is completely blocked and lower is 80% blocked when temperature bellow about +5c/41F.

 

Old problem revisited.
I think my error with the grill partially blocked at 70 degrees. Was an early warning of impending Inverter cooling loop pump failure. Had to have it replaced 4/28/16.

 

I would do no grill block above 50F. Not sure where the radiator for the inverter is on second gen, but best to avoid blocking that, at any ambient temp.