Mpg decreasing

You finally got the thermostat wide open. Which is at 190F. I wouldn't be the least concerened till the temp hit 225F-230F. With a 50/50 mix of antifreeze and water and 15 psi rad cap the coolant will not boil till approx 240F. If your running synthetic motor oil, 225F coolant temp. is well within it's operting range. Also the higher the cooant temp the less engine wear that occures. And the biggest bonus the heater actually works. And the hotter it is the more time it'll spend in stealth. The only condition I'd apply to this is if it starts to spike then it's time to take corrective action, IE: uncover some of the rad. The rad is sized for the worst case scenario 115F A/C on Max and slow moving traffic. 34F heater on max and slow moving traffic is the problem for most of us.

 

I blocked my radiator last winter and it helped a lot. This year I have gone further.

For the radiator I use indoor outdoor carpet squares. I trimmed them so one fits on each half of the radiator. The radiator cover is removed for the winter.

The passenger side carpet just drops in and blocks that half of the radiator pretty completely. The other side has to be wedged down between the radiator and the front plastic piece that sticks over the radiator. I use this feature as a clamp to hold the carpet in any position I want. I keep it up a bit, so the inverter cooler section gets a bit of extra air. If we happen to get hot weather I can raise up like half way and keep temps in range. I have a small gap in the middle too that is not covered, so overall my blockage is about 80% at most.

I monitor temps with scan gauge currently. With my blockage overheat is not a problem in my regular driving at temps as high as 70 degrees. If I was to go on a trip driving over 70 mph or climb significant long hills, overheating could be an issue.

Keep in mind the radiator fans only turn on at like 210 degrees! Stay cool enough so the fans stay off there should be no problem. I am careful to keep the AC off too so that doesn't build up pressure except in really cold weather.

OK for this year I added two more things: I added carpet number 3 behind the radiator and draped over the front and top of the engine. I had to add some protection so the corners don't bend and get into the fan blades! This keeps the air that does get through the radiator directed away from the engine.

I bought a 3M floor polishing pad super fine and glued it to the bottom of the oil pan. Not sure it can handle the heat but it seems to be a good insulator, and it is fine so far. It extends beyond the front and up a bit on the front of the engine. This makes the engine as covered as I can conveniently do with the hoses and wires sticking out all over! I notched the pad around my oil drain. One nice thing is it is a bit stiff and there is plenty to wedge it in with so it is held in place fine till the adhesive dries!

Overall I estimate my final engine temps are about 20 degrees or more higher, and my warm up complete in about half the miles on 40 degree days. Cruising at 55 mph I get temps of 182 instead of 170 in 40 to 50 degree F weather. It stays warmer on slow trips too so I get far more electric mode, at least at these temps.

When temps are below 20 F I will also start out warm with my block heater pre-heat.

Far as I'm concerned Toyota's biggest goof with the car was not providing us a way to keep it warm in winter! My old Saabs all had a radiator shade and you just pulled a chain and it covered the front of the radiator as needed for winter. All small engine cars need help staying warm, but Prius needs it even more with the temperature sensitivity of the catalytic converters and the battery.

And as a bonus I expect to drive without gloves this winter even at -20 degrees F but that may be being too optimistic! Anyway it is already helping me keep my commute mpg up near 50 instead of the low 40's I got last year before blocking anything.

Have not had to adjust anything yet, and we've had weather up to 70 degrees. Car temp is recorded in the Scan Gauge and it showed a peak of 196 the week before I covered anything. It has not gone that high again since blocking the air.

Eventually I'd like to be able to block more and put in automatc louvers so I can adjust things remotely for warmer days as needed.

I tried a pre-heat hose for the air intake last year too, but found little effect, so I may skip that this year.

 

Evan the inverter section of the rad is the bottom approx 1/4 maybe a bit less. That is the only section that I wouldn't cover, reason being is the cooler you can keep the inverter/converter assy the more efficient it become/stays. On my Classic the temp of the inverter is like a roller coaster on the roads that I nomally travel (hilly) rising 50C in a couple of hundred yards sometimes, more so in the summer but still climbs even when it's cold and raining.

The temp gauge sender is at the rear of the ICE as far from the water pump as you can get and as such will probably be about the highest temp in the engine.

 

I don't think its marked but in the NCF manual it shows about the bottom 1/4 also when I was reading in it the thermostat opens and 80-84C 176-183F so this almost makes me want to put in a 195F for the winter months. Like we used to have in years gone by. Driving the 2k4 today I never saw the temp go over 78C so it's getting covers tomorrow. As she does mostly short trips and with the CAN-VIEW she can monitor the temps and if any thing goes out of the normal range she can just crank the heater and open a window.

 

I went out and tried to crawl under and look from above, I could not see a clear division between the ICE radiator and the inverter. Perhaps you could see better with the car on a lift?

 

it might show up on the header tanks on the rad as a line. It's the lower back 1/4 of the rad and all the fins are aluminum so there probably won't be a way to tell from looking at the core. The header tanks will be divided up on the inside and seal to the rear tubes and as such won't show.

 

i like the louver idea. most of my trips are so short in the winter time i doubt that overheating is ever an issue for me. unlike every car ive ever had, i have never seen my Prius when the engine compartment was hot.

even on that 200 mile run up to Diablo Dam, the engine compartment wasnt hot. my other Toyota, i frequently would have the electric cooling fans run for 10 minutes after shutdown. on my Prius, im not sure i've ever heard the fans run.

 

up to Diablo the highest I saw on the MiniScanner was 90C the cooling fans don't come on till about 104C so I had a long way to go. The highest that I saw this summer was 97C and that was on the "hill" on the way home with the A/C on. What did rise was the comverter temp. I don't actually recall it but it was over 100C but once I crested the hill it was back down in the 60's to 70's. It is one temp that really fluxuates and quickly. Part of the problem here is in the winter time the humidity runs around 100% for weeks on end and there is no way to avoid the use of A/C to remove the moisture inside the car so really you shouldn't cover the condenser. On the Prius that poses some problems as it and the rad are ganged together. I'm thinking that if there was 1" of clearance between the condenser and the covering at least the fan's could pull air thru the condenser as needed. As the fans come on when you turn on the defroster button and the A/C there has to be some air travel thru the rad. Maybe winter time in Kansas and the humidity is 4% this wouldn't be a problem but here on the left coast 4 months of rain and 30-35F or 1-3C and if you don't condition the air your standing in water in the foot wells, foget how hot it is inside the car.

 

You can see the radiator sections looking at the ends. There are separate chambers for the top section form the bottom since the fluids are entirely separate. I think it shows on the driver side best.

 

At almost 5000 miles, we have yet to come close to that.
Best tank was just under 45, more like 42 lately. It's not particularly cold.

Since California summer gas is now equivalent to most states' winter gas,
I wonder what they are putting in our winter gas this year.

 

So how are you attaching the carpet to drape over the radiator? Frank you know it is a pain for us "suthener's" to translate that C stuff. I am good to 40 but much above that people die and I have no idea what you are talking about! Of course I do endometrial ablations at 90 C and that is almost boiling, but I don't relate that to radiators. The highest temps I have seen are 192F (89 C) but usually 180'sF (82 C) is a high. So Frank how do you order beer?

 

I'll have a Corona and at 4C please..........blank stare!

 

My carpets are not attached. They are stiff enough to just sit between the radiator and the front grill. There is some leakage around them, but that still blocks just about the right amount for temps around Boston.

The drivers side carpet is held by the top plastic thing as I mentioned to keep the bottom section open on that side. So it just hangs down 3/4 of the way on that side.

I used 3M trim adhesive on the oil pan for the insulating floor polishing pad, and the rest of it is held by wedging against the frame the bottom plastic, and the oil filter.

 

I think I will get one and start there now that it is getting cooler. Do you get them at Home Depot or Lowes? I would guess something without an adhesive on it. Do you cut to size?

 

I got carpet squares at Home Depot. Just plain indoor outdoor carpet that looked thick enough to last. No special backing, and not the plastic grass kind. I trimmed a bit to size on the width with metal shears.

 

IN THE WINTER THE GAS FORMULA CHANGES, THIS IS ONE REASON. THE OTHER REASON IS WE ARE USING THE WEATERS/DEFROSTERS. THIS NEEDS THE GAS ENGEN TO RUN , TO WARM UP THE CAR. THE ELETRIC ENGEN WILL NOT PRODUCE THE HEET LIKE THE GAS ENGEN. THUS MORE GAS BEING USED ,AND DROP IN MPG. IT'S JUST LIKE TURNING ON THE AC IN THE SUMMER. THE DROP IN MPG.