MetroMPG.com mailbag: Metro engine won't stay warm in super cold weather

[MetroMPG]

This isn't the first time I've heard this story about the little 993cc motors in these cars in extremely cold conditions ... (like -20 C / -4 F and below):

It's been real cold lately and driving the Geo is just brutal in this weather. I have a piece of cardboard covering 100% of the front of the radiator yet the engine still dislikes warming up (and even reaching a warm state, the temperature gauge will slide all the way back to the "C" mark if left idling).

I was talking with a guy today and he said that there's probably something wrong with my thermostat as he believes that the coolant in my car shouldn't circulate at all until a certain temperature is met.

Is this true with the Fireflys/Metros?

Feel free to jump in with other diagnoses & suggestions, but here's my reply...

[MetroMPG]

The guy's right: the coolant shouldn't circulate until the engine has warmed up. That said, I've heard before that the Metro will slowly fall from normal operating temps when idling on a really cold day, like you describe.

That doesn't necessarily mean the t-stat is faulty though. It's possible the engine just doesn't generate enough heat @ idle (0.5 litres per hour is what I measured with mine fully warmed up).

One method of testing the t-stat that comes to mind is opening the rad cap when cold, starting the engine and watching to see if the coolant circulates when the engine is revved. You should be able to tell when the t-stat opens, because the coolant level will change noticeably & it will start flowing.

Mod idea: What about a fire proof insulation blanket you can place on top of the engine, or attach to the hood to keep more heat in the engine compartment?

[LibbyMetro]

i had to jump lil red this mornin off of da honda , and let it warm up for a good 20 minutes not to let the engine warm up , but to de ice the windows it was -10 this morning and the inside of the car was iced to, the heater isnt exactly great so it didnt even finish deicing the car while i drove 60 miles, interior never warmed up, but but temp gauge always reads dead center

[MetroMPG]

You'd be better off pluggin in a hair dryer or small space heater to warm up the interior than letting the 993cc motor idle to try to accomplish the same task.

You've seen this, right? And it was at much warmer temperatures.



source: Mini-experiment: cold start fuel consumption and warm-up time

I assume you either don't have a block heater, or have no place to plug in.

[Who]

Wouldn't a super-insulated engine block be nice? If it could hold a good percentage of the residual heat for up to 24 days and not be too heavy it would certainly be ideal for those of us in northern climates. Where's the asbestos when you need it?

I used to use a 1000 watt car space heater in my Fiesta ages ago when we got real winters. Without it, the doors wouldn't open.

What would be nice is if a space heater, block heater, battery charger, outdoor temperature sensor (which is already on all cars with TPMS) and a timer control could all be integrated right into new cars. As you shut the car off at night, you tap 7am on a console control and plug it in. It monitors the temperature of the interior, block and outside temperature and has the car ready at 7am for you. Sherrazhell beats all the remote starters that are way too prevalent around here.

[LibbyMetro]

lol trust me you dont want asbestos , i remove that cancer causing crap for a living , go to youtube and do a search on libby montana and youll see what i mean. I had never seen that graph, but glad you showed it to me , i will be purchasing the block heater as soon as i can afford it.

[Coyote X]

First thing to check is to make sure the car has that blank panel beside the radiator still so cold air isn't hitting the motor directly and cooling it down. If that panel is in place I would say next would be check the thermostat. It is probably not closing all the way. In the summer it won't matter but in the winter even a little bit of flow out of it would make the car run cold. I just got a new 195 thermostat at the auto parts for $6 today, I just noticed that I only had a 180 in there. For the price of them it is no big deal to just replace it if the guy even halfway thinks it is bad.

Also some people bypass the fan temperature switch when it goes bad and just let the fan run all the time, if the car has the fan always running then putting the switch back would help keep it warm.

If the car still won't warm up I would recommend restricting the tail pipe down by about half so there is only a 3/4"-1" hole out the end of the pipe. That will help warm it up faster and keep it warmer.

[Peakster]

The 1.0L engine has no problem staying warm and generating cabin heat at steady highway speeds. The problem is when driving in stop/go traffic.

One particularly cold night (-30*C) I drove to the closest movie store about 4 miles away, all surface streets with speed limits between 30-45 mph. I never shifted higher than 3rd gear, even on the 45-mph stretch (in that I was doing 50) and the temperature gauge was almost in the middle by the time I arrived. Not quite fully warmed up though. I decided to leave the car idling while I looked for movies to keep it warm. 15 minutes later I came back and the temperature gauge was right back on the "C" again!

That tells me that the radiator fluid is swishing around at all times, regardless of temperature. Honestly, if radiators didn't circulate liquid until a hot temperature is met, what would be the purpose of blocking off a radiator like so many do in the winter?

[MetroMPG]

Originally Posted by Who

Wouldn't a super-insulated engine block be nice?

Sure - if it (the insulation) went away once the engine heated up, and came back when you switched things off again. I suppose that's why the Prius designers decided it would be easier to shuttle around the warm coolant.

[Who]

Wouldn't a super-insulated engine block be nice?

Originally Posted by MetroMPG

Sure - if it (the insulation) went away once the engine heated up, and came back when you switched things off again. I suppose that's why the Prius designers decided it would be easier to shuttle around the warm coolant.

Darin, any reason why the cooling system, and that would include an external oil cooler, shouldn't be able keep a super-insulated block at optimal operating temperatures even in the summer?