Cold Temps affecting my Prius

As far as I know, all cars are impacted, Prii we just see it better. There is a long list of reasons: seasonal gasoline changes, lube oils thicker in colder weather, tires have greater rolling resistance, the heater requires more ICE running, etc.

Mitigation factors would be keeping car warmer in garage or via engine block heater, using lube oil with lower temp performance ie; 0W-20. People put foam inserts in the front grill to stop as much cold air coming into the engine, some insulate under the hood, and finally some hacks (advamced topic) to reduce warm-up cycle.

 

One of the reasons I'm taking a "Relook at warm-up" is to get some empirical data to optimize cold-weather operation. There are several mitigation strategies which "search" can provide more data:

• bumper inlet block - needs to be done carefully but can reduce aerodynamic drag at some risk of higher temperatures
• lubricants - transaxle oil is particularly sensitive to colder temperatures
• engine block heater - should be a no-brainer
• cabin space heater - another easy solution (using extension cord from house)
• warm-up driving profile - why I'm doing a "Relook at warm-up"

Bob Wilson

 

Bob- I have been thinking about inventing cabin space heater...already invented?

 

Cabin space heaters are already available, seen them for sale on Jeep part stores.

 

After reading several posts on here about grill blocking, I decided that since our morning temps. have fallen below freezing, it was worth a try. Completely blocked the lower grill and left the top one open, as some suggested, to allow cooling for the inverter. My morning drive is about 2 miles with moderate hills and then freeway with about a 600' elevation change down into town over about a 6-7 mile stretch then flat for 3 more miles. Heading home reverse that route. Morning temp. this first day was 31 F. Afternoon reached 55 F. I monitored the coolant temp. with Torque Pro and OBD II reader. Going into town, the coolant never went above 190 F but coming home it hit 207 F. As soon as I got off the climb and back on the final 2 miles, it stayed around 195F. I don't like the 207F on my new car so I'm going into town and immediately back in the morning tomorrow while the outside temp. is still cool both ways and once I get home I'm going to remove the grill block completely for an after noon run over the same route to compare today's readings. If anyone is curious, I'll post my findings when I know more. Right now, I'm thinking I'd rather sacrifice mpg than over heat my engine.

 

The 207F seems high. I block 66 to 75% of my lower grill, and haven't seen temps go higher than 197 (and more often they are in the normal high range of 190 -195F). What I do find is that the car heats up more quickly, so I can get the heater on sooner (after the car clears 159F) in cold weather. With leaving the top open, I've not seen any unusual temperatures with the inverter (which usually runs 10 - 20 F higher than ambient (20F in slow traffic)).

Normal "cold" temperatures here are 28 - 39F.

I'd just remove the top grill block and one tube from the lower blocks and you should be fine.

Did you run the heater? That will help cool the engine and warm the passenger cabin (win!)

 

I never blocked the top grill so that's not a problem. The coolant temp. this morning (30F outside), reached 197F briefly on the climb back home but went right back to the 195.8F almost immediately so I'm guessing that the thermostat opened and maintained that temp. for the remainder of the climb. After leveling out it went to 188F or less depending on if I hit EV or how frequent I hit it. No long hills= no problem. Long hill with temp. outside in low 30F= no problem. Long hill with outside temp. >45-50F may be a problem with full grill block. It's supposed to hit 61F today so I will be taking the grill block off before going to town and back this after noon. The forecast for the week is 64-34F Friday, 66-36F Sat., 49-27F Sunday, 48-27F Monday, 55-32 Tuesday, 59-33F Wed.. As you can see, the morning are fine for grill block everyday but the afternoons present a problem for the climb back from town. Sunday and Monday may be ok but putting the grill block (or even modifying it) everyday is more than I'm willing to do. I can see that an automatic louver (even a manual one that is easy to change) would be a great modification for myself with the temp. variables I encounter and the route I must drive. If my route were reversed, no problem as I would be climbing when the outside temp. is low and gliding when it is warmer, but I'm not moving anytime soon. Yes I did run the heater. My wife is always cold, so I have it set to 68F auto with A/C off and outside air selected. I also use ECO mode so it runs the fan speed lower as I understand it. If the front glass starts to fog, I hit the front defrost button and the fan ramps right up until I hit the button again when it's clear.

 

This is my first winter with my Prius. I am experiencing a similar drop. But having hung around Prius Chat as long as I had before buying my Prius this was not unexpected.

Hey, I don't know if I would call it "The Prius isn't made to thrive in cold temps".....as all vehicles suffer a mileage drop in colder temperatures. It's just with Prius....and all the software and feedback, most of us are more aware that it is happening.

44-47 MPG? is great MPG. And it gives me another reason to look ahead to Spring.

Some have tried Grill Blocking and Engine Block heaters to minimize the winter hit. I think I'm just going to roll with the drop...

 

My drive into town and back this afternoon without any grill blocking produced a high coolant temp. of 199.2 briefly on the climb back to home. The outside air temp. was 60F at the time. The thermostat opened and the ICE temp returned to 195.8F and remained stable at that temp. for the remainder of the climb. This makes me conclude that grill blocking will not be on my list of tactics to use for my own situation. I would like to try an engine block heater but after inquiring at the Toyota service department and following up on other places that were recommended, no one seems willing or able to do the installation. One shop said they would be happy to learn on my car as a guinea pig for them to learn on as I pay them. I'd rather attempt it myself than that scenario. Looks more and more like I'll just have to accept the mpg drop this first winter also, unless another viable solution presents itself. I'm even considering insulating and heating my garage but that doesn't seem very cost effective.

 

I don't think so. Seems like the thermostat must be set to maintain that temp.

 

my temp goes up to 93 degrees celsius almost on every (even small) hill (driving at 55-60mph) so I guess it is normal. I currently block 50% of the lower grille and this does not seem to have any effect on the temperatures as I had the same without the blocking.

best regards

Andrej

 

There has been at least one thread about how to install the Toyota block heater but I suspect you'd be disappointed with the overall effect on your mileage.
My take on winter mileage is that it's less about start up temperature and more about the temperature you're driving through and its effect on wind resistance, rolling resistance and resistance from colder lubricants, etc. With its exhaust-to-coolant heat exchanger the Gen III Prius really warms up pretty quickly on its own.

 

I'm using grill block, 50% of lower opening when daily max stays below 18deg C, 100% once temps are around or below 0deg C.

Also use our block heater, year 'round, aiming to have it plugged in for a couple of hours before first drive of the day.

A good trick is to simply consolidate trips as much as possible, and reduce short distance impulse drives.

And here's an engine bay block I leave in, year 'round:

 

So I have been looking for a couple of hours now trying to get more concise instructions on how to block the grill of my 2013 prius.

I live in Buffalo and drive pretty much exclusively on flat-ish roads, so temperature and load are both low. Looking for 1) what to buy 2) brief explanation on how to alter the insulation to fit 3) a finished product so I know what to shoot for.

 

1. Buy 1" PVC foam insulation pipe;
2. Cut appropriate lenghts for each grill opening;
3. Cut slots for internal grill vertical ribs;
4. Push inside;

 

Sweet, thanks a lot Les. Exactly what I was looking for. I thought it was gonna be that easy, just wanted to make sure.

You notice a worthwhile increase in mpg I assume?

 

The pleasure is mine

It is hard to say yet. Previous winter I didn't drive the Prius too much - I drove my ship on East Atlantic Coast so my car was hibernated in the garage. The present season - I've just blocked the grill couple of days ago - no statistics yet.