need longer trips (>10 miles) for cold engine,

[bzipitidoo]

I just can't get good mileage when I start out with a cold engine and only go 10 to 15 miles. Winter makes it worse, but I see it in summer too. Temperatures where I'm at have been around 40F now, and often hit 100F in summer. I've got a Metro (automush tranny unfortunately), and on a 10 mile trip, all city driving, starting out cold, I'll see 28 mpg or so at first and gradually climb to 35 mpg by the end of the trip. If the engine is warm from being driven recently, and I take a 10 mile trip then I start off already at 33 mpg and end at 40 mpg or better.

That's a pretty big difference. I thought of maybe trying a block heater, but I'd need that engine nice and hot, say, 140F minimum. I have the impression block heaters are only intended for very cold climates to get the engine up to maybe 50F tops. So, what to do? Store in hot garage best I suppose, but that's not easy, and is no help for coming home from wherever I went. Some of the crazier thoughts was wrap the engine in insulation? Pour very hot water over the engine before I start? Paint the hood black? Anyone have some more practical suggestions?

[Erdrick]

I personally say be happy about it. That is.. if you are talking about a commute. If you have a 10-15 mile commute, then you should be ecstatic. If you are talking about trips for errands and what not, then why not just consolidate?

You are on the right path, and seem to be thinking about your options. I am going to guess that most people are going to steer you in the direction of a block heater.

[brucepick]

I've seen posts elsewhere from FE people who are using block heaters year round and very happy with them. For exactly the reason you described, bzipitidoo. Of course it takes less long to preheat the engine in warmer weather. And your local sources of parts and installation labor will think you're nuts to use it in warm weather, but that's their view.

From reading around on the topic, it seems the best design is the one that installs in a freeze plug and heats the engine coolant directly.

Not sure about the "tank" type ones that install a tank in the heater hose path - heat has to work its way through the hose into the block, not ideal. Oil pan heaters will warm the oil but not the whole block. Dipstick heaters seem to have the most problems.

[JanGeo]

Sounds like your thermostat is leaking water past it when the engine is cold. Next chance you drive stop after a mile and see if the radiator is warm while the engine is still cold and that will tell you that the water is circulating before the engine is fully warmed up. If you want more engine heat then block off the grill but not the radiator so that the fan can still work when needed.

[kamesama980]

Textbook example of a thermostat staying open. replace it and let us know how it goes. toyota parts FTW

[yi5hedr3]

Originally Posted by bzipitidoo

I just can't get good mileage when I start out with a cold engine and only go 10 to 15 miles. Winter makes it worse, but I see it in summer too. Temperatures where I'm at have been around 40F now, and often hit 100F in summer. I've got a Metro (automush tranny unfortunately), and on a 10 mile trip, all city driving, starting out cold, I'll see 28 mpg or so at first and gradually climb to 35 mpg by the end of the trip. If the engine is warm from being driven recently, and I take a 10 mile trip then I start off already at 33 mpg and end at 40 mpg or better.

That's a pretty big difference. I thought of maybe trying a block heater, but I'd need that engine nice and hot, say, 140F minimum. I have the impression block heaters are only intended for very cold climates to get the engine up to maybe 50F tops. So, what to do? Store in hot garage best I suppose, but that's not easy, and is no help for coming home from wherever I went. Some of the crazier thoughts was wrap the engine in insulation? Pour very hot water over the engine before I start? Paint the hood black? Anyone have some more practical suggestions?

28 mpg is not bad at all for a cold engine!! You probably only see this for the first mile, so I wouldn't sweat it. Motor on!!!

[Snax]

Originally Posted by brucepick

Not sure about the "tank" type ones that install a tank in the heater hose path - heat has to work its way through the hose into the block, not ideal. Oil pan heaters will warm the oil but not the whole block. Dipstick heaters seem to have the most problems.

I installed a tank style 1000W heater in my Tercel and I could not be happier with it. The main reason I chose the tank style was because of the higher wattage and quicker heating capacity. Instead of leaving a lower power heater on overnight, wasting allot energy to ambient heat loss, I have mine setup on a timer for 45 minutes before I leave for work. That is just long enough to start giving me useable heat at startup and drop down to a high temperature idle within seconds.

Another benefit of the tank style heater is that it encourages convective flow through the entire engine (and the heater core too in some cases). When it is installed correctly, the upper hose gets too hot to touch within a couple of minutes while the cold line underneath continually feeds in fresh coolant.

[brucepick]

Thanks Snax. Now I understand better about the tank type heaters. Looks like a good setup. Of course you need a good place to put it and route hoses etc. but the concept makes good sense.

[Snax]

Yeah, figuring out the installation was the most challenging part of it. They absolutely must have a sginificant vertical rise without any kinks in the line to work effectively. I ended up having to mount mine down at the level of the oil pan to get enough rise. Anybody with a crowded engine compartment would have a fun time trying to make that work. Fortunately the Weber carb I installed helped to clear the way, that would otherwise have been a royal PITA, for working on it.

[Project84]

I use block heaters on my fleet of vehicles at my job... Napa tank style 15000 W heaters PUT OUT SOME HEAT in a hurry.

15000W is a bit much of a standard duty car, my application is heavy duty F700 box trucks.

Napa sells a 7500W tank style heater and for a good price. I'd install one in my car but I live in an apartment and have no way of having an electrical connection in the parking lot.

[8307c4]

I would recommend driving it real nice and easy for the first 2-3 minutes.
That's likely your best bet.

Because...
The only time a block heater is effective is when the climate is so cold that the oil gels and the battery doesn't have the power to turn the engine, and the only reason this is considered effective is because the car will not start any other way... However, any other reason for it we're just dumping saved fuel money into the electric bill and then some.

Even 1,500 watts is not enough to make a difference, it provides just enough heat into the oil pan to keep the oil semi fluid in sub freezing temperatures but the entire area under the hood is hardly what I would call insulated for the purpose of actual heating. So there's a small pool of semi luke warm oil down in the sump but the rest of the engine is and stays frigidly cold even when left plugged in 24-7.

Might as well stick a 1500w space heater on the front porch and run it 24-7, that is pretty close to how effectively the heat under the hood of a car is dispersed into the atmosphere, and these things consume kilowatt hours.

To understand kilowatt hours it's simple: Take any appliance that consumes 1,000 watts and run it one hour, you have just consumed 1kwh. Run it 24-7 and we're talking roughly 720 kwh a month, I would be willing to bet most electric bills average around ~1,500 kwh a month so +700 kwh's is going to make a difference in the bill few will fail to notice.

By the time we get enough heat to actually create some warmth we're consuming so many kilowatt hours I would dread seeing the electric bill even more than I hate filling up gas, but it's either big enough or it isn't... Either way it's not cost efficient, other than purely for increasing mpg it will cost more to use a heater than if we don't.

[dkjones96]

Open thermostat? No way is this an open thermostat issue. He didn't say it didn't get hot, just that it gets bad mileage.

I'd be ecstatic about the mileage you are getting. Most cars get around 1/3-1/2 hot mileage in winter and a little better in summer. I'd be surprised if I see better than 9-12mpg my first 3-4 miles. I average 22.5 60/40 city/highway on my 12 mile trip to work.

There isn't really a way around this except for pre-heating the engine. The clearances are really loose, oil thick and atomization lacking so badly on a cold engine it's amazing most of them run as well as they do.

[brucepick]

Originally Posted by 8307c4

I would recommend driving it real nice and easy for the first 2-3 minutes.
That's likely your best bet.

Because...
The only time a block heater is effective is when the climate is so cold that the oil gels and the battery doesn't have the power to turn the engine, and the only reason this is considered effective is because the car will not start any other way... However, any other reason for it we're just dumping saved fuel money into the electric bill and then some...

I agree with the first statement: driving it real nice and easy for the first 2-3 minutes.

However with all due respect, I take exception to the rest.

Until recently when fuel cost has become a real concern, its true that the only use for a block heater was in frigid temperatures where an engine would not start otherwise.

However we who track fuel economy seriously have learned that an engine is much less efficient while warming up. And those who have installed block heaters or tank type heaters have been able to document improved fuel economy. They have also documented that the cost of the electricity is far less than the cost of the fuel saved by using the heater.

There are several reasons:

#1: You described a process where the oil at bottom of pan is warm and the rest is ice cold. This is not how a block heater operates, you've instead described the operation of an oil pan heater which is not under consideration in this thread. We're discussing block and tank heaters which warm up the coolant and thus the block. Heat transfer to the block is very efficient, though granting the losses due to lack of insulation. Those losses are the same regardless of how you warm up any given engine so I won't consider them.

#2: The cost per BTU, or cost per energy unit, of electricity is far lower than that cost for gasoline or diesel fuel.

#3: Following from the lower cost of electrical energy, the job of warming up the block is less expensive when you use wall current to do it. Otherwise, you're basically burning fuel to create heat to heat up the block.

#4: The engine itself operates at lower efficiency during warmup due to the richer mixture that's needed when the block is cold. The sooner you can get the block up to the temperature where it can operate at its optumum air/fuel ratio, the better the fuel economy will be.

[Snax]

For the record, two hours with 1000W tank heater on, with 25F ambient, brings my motor up to full operating temperature. That works out to 2kWh/18 cents. Now even if I only save 18 cents worth of gas by doing this, I have a car that is easy to start with defrost heat at the ready.

Tank style heaters work very well, saving fuel, saving time, saving emissions.

[Hateful]

hot air intake may help with little cost.