-15F outdoor air temps = luke warm cabin heater air temps

Hi Optimus,

We actually do not block the radiator, but the grill. This is typically done with plumbing pipe insulation. Split it appart and fit each side into a grill opening. Put knife slices into the foam so it will fit around and grab (a little) the vertical grill struts. Oh, I just realized you are driving a Gen I. On the Gen II's the gap between the radiator and grill, underneath, is aerodynamically blocked. So, blocking the grill prevents air from getting to the radiator (mostly).

There is an Australian on-line car magazine called Autospeed, which shows how to mod the Gen 1 the same as the Gen II.

Also, there is a guy (John1701 in here) with a web site about the Prius. He is from Minnesota.

And at -15 F, you might want to consider a block heater too. These are available from Toyota of Canada, through several outlets on-line. Metro Toyota in Ohio is one of these.

 

block your radiator and do it anyway you can. because of the lesser degree of waste heat a Pri generates, you will have issues getting AND KEEPING your car warm.

we are in the middle of a cold snap (this morning lows were 11ºF that is a mere THIRTY DEGREES BELOW NORMAL). now yesterday on a balmy 21ºF day with a mild 10-15 mph breeze, the Pri struggled to get past 160º.

now, i would heat it up to 160, turn on heat (set to 70) it would run about 2 mins and temps would be back to as low a 145º. i have my grill blocked 100% ( i block it as soon as the temps go below 50 been doing it 3 years now, no issues)

so besides having difficulty warming up, running the heater GREATLY dissipates heat that is built up. now granted, this is city driving conditions, but even on freeway (average speed for these conditions are only slightly higher at around 35-40 mph but at least no stops) i probably will not see 180 unless i drive for an extended period.

my method of blocking (granted some air will leak) is pieces of pipe foam insulation in the grill slots. i do ½" for smaller lower slats split in half and whole ½ for uppers with ends tapered for a better fit. not perfect since several pieces will leak, but without a damper system for better wind blockage, anything else would be inconvenient since i am looking for something simple and easy to remove if temps ever get too high ( have run car with OAT in the upper 50's without issue either...jus watch temps closer is all)

**edit**

GREAT!! go out to car, its about 10º. start it up to warm it up. switch to heat, car so cold heat no run... so turn off heat in order to warm up car and go inside and before i take two steps out of car, ENGINE SHUTS OFF!!

so now i have to run defrost which makes car not heat up!@! man !!

**update**

ok, getting oil changed today, so drop off SO to work, on way there heat on whole time, max water temp 146. air intake bouncing between 31 to 35 (started at 18 this morning!!).

i drop her off, turn off heat, run until car heats up to 175... turn heat back on...in less than 2 mins, temp back down to 155...sooo, as you can see, blocking the grill is PARAMOUNT!!!

 

Here are some other ideas:
2003 Prius - Cold Weather and Transaxle

The first year, I used fiberglass re-enforced packing tape to completely seal the lower inlet. But then you have this sticky stuff to take off in the summer. My current practice is a split 'water noodle' held on by bungie cord loops.

I live in North Alabama but you may find some of these notes useful:
2003 Prius - Cold Weather and Transaxle

BTW, I'm finding the block heater provides a 10-15 C rise in temperature. Better than nothing, we're not talking fully warmed up.

GOOD LUCK!
Bob Wilson

 

Hi Bob,

At -15 F, one is going to have difficulting with any pressue sensative adhesive. Unless it was applied above freezing.

Its best to get the thinner tubing insulaton foam, and either slit it, or seperate at the built-in seam, and stick it into the grillwork. The thinner foam has a wall thickness that will insert between grill bars. With my Gen II I can bridge 1 slot, covering 3 with 3/4" tubing foam. Or with 1/2 " diameter tubing foam, bridge no slots, and insert the foam into two adjoining slots.

 

The NHW11, 01-03 has a single horizontal bar in the middle of the front bumper air intake. The NHW20 has the multiple, smaller bars/vent slots. But I'm surprised duct tape wouldn't work even in that cold of weather.

Bob Wilson

 

Hi Bob,

It will stick initially, but the bond will be poor, and it will fall off. Its because the surfaces are so cold, that the intimate contact needed to get the microscopic static electricty attraction never occurs.

Probably best just to use some ty-wraps (zip-ties) and hold the thick tube insulation on that way. You are using a pool noodle. But, they do sell tubing insulation that thick up here.

 

Been there, but didn't do it...



3 winters in Minnesota with my Classic Prius were fine. I'm one that never cared for hot from the heater.

4 winters in Minnesota with my Iconic Prius were that way too.



Then last year, finally having a scantool available, I gave grille-blocking a shot. The climate here is too cold to show much of a MPG improvement. Efficiency pretty much bottoms out. But can squeeze out more heat that way.

Details of what I did are in the User-Guide.
.

 

We had the temperature fall to about 18F the other day, and in my 12mile commute the scangauge said that the coolant never went above 68 degrees C. The cabin was freezing even with heat on, and the coolant fell by about five degrees C when I turned the heater on. I used a scraper on the inside of the windshield for the first time since I owned a '65 beetle. This didn't happen last winter, 18F isn't so cold, so I am convinced that my Thermostat is in need of replacement, even tho' I only have 18K miles on the car. I've had Thermostat problems in other cars in the past, albeit at much higher mileage. I'll post if this fixes the problem after tomorrow's service. BTW my fuel efficiency has been much worse for a month or so, and I was wondering why...hopefully I've answered that question.

 

nyty; what you see is very normal. that is why grill blocking is so important. in F terms, i dont use defrost if i can get away with it until i hit at least 160. but when i turn it on, i immediately start dropping in temperature especially at street speeds. stop at a light, lose another 5-10 degrees, so its a battle to keep the vehicle warm when its cold out.

 

I am in Minnesota also, each winter has a week where we never get above zero. But the cabin heater has always been great (2006 if I recall correctly). Previously I had a T100 and this really had a weak heater. The gas mileage really goes down though.

 

I can't offer you advice based on experience with Gen 1 in cold climates, but I do suggest you take a look through John1701A's website. (He posted early on in your thread and referenced his own site.)

I have a 2007 Gen 2, and I've been grill blocking both winters I've had the car. I find it makes a significant difference in how quickly I get heat from the car. When it got down to -24F about two weeks ago, it was impossible to get heat for the first 10 minutes of driving. This is no different than my previous cars, however, so I am not concerned with the heating ability of my Gen 2.

I wish you well, and I re-state my suggestion that you look to fellow Minnesotan John. He has had both the Classic (Gen 1) and Iconic (Gen 2) Prius.

 

I just wait for the heat to come on automatically (the heat is "on" but the car is waiting until it can provide warm air). I like this feature. At least I am not blowing cold air on myself.

 

I understand what you are saying, but I believe you've missed my point.

When it is -10 or -20, the heat, though turned to "on" will not begin providing heat until the engine has warmed up to a minimum point. If you have an electric block heater or you employ grill blocking (or both, for an even greater impact), you will arrive at that engine temperature sooner, thereby providing "auto" heat that much earlier. An alternative, if MPGs are more important to you than toasty toes, is to wait for 5 minutes before turning on any kind of heat. At that point, you could put the heat on a low setting, or simply turn it to Auto.

Regardless of the above issue with MPGs, you've stated your issue with the cabin heat. I am suggesting, with anecdotal evidence in support, that you will warm up sooner and more completely if you are engaging one or both of the above-named techniques. Grill blocking is less expensive, and it will provide you with a very significant chance of a "warmer sooner" experience. It also will continue "giving" you better heat, because it will keep the ICE from losing its heat as you drive.

I've just started to enjoy the EBH (THANK YOU FIRE ENGINEER!), and I've noticed both quicker warming and higher MPGs. Hmm . . . No, I'll still say you should start with grill blocking, but don't ignore the benefits of an EBH.

 

i can agree that putting on heat, even in the auto setting, will not blow cold air but will start blowing much too early and greatly delay effective heating much longer.

i have seen during winter (relatively mild compared to you guys!!) during real cold snaps of 20-25ºF where water temp is 150º, turn on heat and water temp will drop to 140º in a few minutes. so what i do that is effective (it really depends on specific temperatures, so experimentation might be the key here) is let it heat up to 175º then turn on heat, turn off heat when temps hit 155º. wait for it to heat back up and so on.

now, the unfortunate thing about my area is the 99.9% humidity every winter morning (rare is it when its not saturated) requiring defrost to run which is not temperature controlled. iow, it will run even when blowing straight cold air...

 

Doesn't look like anyone has posted here since it was cold.

I believe my 03' Prius' heater is worse off than normal because while troubleshooting a blown headgasket I put in some radiator sealer and I fear it is partially blocking the heater core.

First off is the question of if anyone knows a good idea of getting it cleared without spending a fortune?

Next question is if anyone has added some sort of supplemental heat? we've got that nice electrical source there, I was trying to contemplate some sort of electric heater... If there were a decent attachment point, seems like a 750watt heater would be feasible off the 12v... Or am I asking too much with all of the other 12v accessories likely running at the same time in the winter? And even then there's the question of where/how exactly one would set this heater to be useful and safe...

I was really hoping those electric heaters in the heating system would do more, but I can't even tell they're doing anything at all... Is there a fuse or something I can check with a voltmeter to confirm that they are coming on? And if so, is there a temperature limit to when they come on? (i.e. would they come on if I tried defrost right now with 70F outside temps?)

Thanks!
Levi

 

I'd suggest getting at least volume 2 of the NHW11 maintenance manual. This will show you all of the systems and improve your luck diagnosing what is going on. Kudos for thinking of your heater before the winter returns.

Several thinks pop to mind:

• bleeding air from the heater core - I can envision trapped air making it less effective. How to bleed it, I don't know.
• heater coolant pump - located above the transaxle, the inverter has to move to reach it. This circulates coolant when the engine is off so don't rule it out.

Again, kudos for looking at the problem now instead of the dead of winter.

Bob Wilson