For those with block heaters

[grsthegreat]

First off, block heaters should be attached to a thermometer or block cube unit. It doesnt need to run in spring thru fall for most locations. All generac heaters have inline thermostats so only run when temp parameters are met.

It seams weird that all block heaters are such power hogs. I heat a 100gal water trough for my horses with a 250w heater. You would think a block heater could be alot smaller.

 

[bdhsfz6]

First off, block heaters should be attached to a thermometer or block cube unit. It doesnt need to run in spring thru fall for most locations. All generac heaters have inline thermostats so only run when temp parameters are met.

It seams weird that all block heaters are such power hogs. I heat a 100gal water trough for my horses with a 250w heater. You would think a block heater could be alot smaller.

Although I agree with you, the generator manual says a minimum warmup time of 10 minutes at temps above 32 F. No high limit is stated. Personally, I think this is overkill and just an abundance of caution.

The load factor is also a consideration. In my case, I can't ever imagine a situation where the generator would ever be put under full load at startup. It's rated at 11KW and the house load rarely exceeds half that.

 

[Beaver Cove Deere]

It greatly increases the risk of fire.

Voltage drop due to cord length or plug condition can only INCREASE a resistance heater's expected life time.

 

[DarkBlack]

I'm considering a block heater for my new diesel generator but I question the economics. The OEM block heater would draw 500 watts continuously, and based on current electric rates, will cost almost $500 per year to operate. The manual says if operated correctly and warmed up before use, the life expectancy of the diesel is 6000 hours. On average, I use a generator less than 100 hours per year, so in theory it should last 60 years. Over that time, the block heater will use $30,000 worth of electricity. The generator cost $10K and could be replaced several times, instead of paying that much in electric bills.

I realize these numbers are not absolute and can be affected by many things. Electric rates, inflation, machinery costs, using a heater timer or thermostat, etc. will all change the economics. Even if operating the diesel without fully warming shortens it life by half, it will still be more economical to replace the generator than pay for the electricity to keep it warm.

I always warm up my tractors before use, the economics for such an expensive machine are quite different. The auto start transfer switch for the generator only allows a 5 minute warmup before applying load. The manual says it should be 30 minutes when the temp is below 32F.

It doesn't get much below 0 F here anymore and the generator is in an unheated building, which buffers the outside temp somewhat. My diesel tractors all start on the coldest mornings without the aid of a block heater and if the generator does as well, I see no practical need for a block heater.

30 minutes “warm up” time below 32F is just a bad recommendation in my humble opinion. You’ll be doing more engine wear, wasting more fuel , more pollution , for 1/2 hour. The engine is already starting up to full rpm’s..you’re not “gently” warming up at a slow speed , anyway.
1/2 your engine parts aren’t even subjected to the crankshaft load, such as the oil pump, camshaft, lifters, rocker arms, valves, timing chain, etc…

Run a 5w-xx oil. If you’re still worried, buy a heater, and only plug it in on the very coldest winter days.

 

[bdhsfz6]

30 minutes “warm up” time below 32F is just a bad recommendation in my humble opinion. You’ll be doing more engine wear, wasting more fuel , more pollution , for 1/2 hour. The engine is already starting up to full rpm’s..you’re not “gently” warming up at a slow speed , anyway.
1/2 your engine parts aren’t even subjected to the crankshaft load, such as the oil pump, camshaft, lifters, rocker arms, valves, timing chain, etc…

Run a 5w-xx oil. If you’re still worried, buy a heater, and only plug it in on the very coldest winter days.

I agree.

I may experiment with an old magnetic oil pan heater I have laying around. It only uses 200 watts. I may hook it up during the winter months. Better than nothing I suppose.

 

[bdhsfz6]

I am a fan of block heaters, but I would certainly not run a heater 24/7 (even just in the winter) on a standby generator with an automatic transfer switch. That $30,000 number is an eye opener!

I will pre heat my tractor for 3 hours if there is snow in the forecast that I think I'll need to plow. For power outages, by the time my tractor is hooked up to the pto generator it's warmed up enough to transfer power.

I always warm up my tractors as well. 20 minutes or so on a cold winter morning gets the cab nice & toasty.

A generator is a different animal though. The automatic transfer switch doesn't give you much flexibility in setting a warmup time. I may just convert it to manual start. That way, I can warm it for as long as I like before connecting the load.

 

[bdhsfz6]

Anyone have an opinion on using a magnetic oil pan heater? I know they can be a headache to use on vehicles, but I don't see a problem using one on a stationary diesel generator.

I know some engines have cast aluminum oil pans, so some other means of holding it in place would have to be used.

 

[John_Mc]

Anyone have an opinion on using a magnetic oil pan heater? I know they can be a headache to use on vehicles, but I don't see a problem using one on a stationary diesel generator.

I know some engines have cast aluminum oil pans, so some other means of holding it in place would have to be used.

Piston aircraft engines commonly use an oil sump heater. These are generally glue-on. You do want to make sure the oil sump heater has some sort of temperature control AT the heater. Some high powered oil sump heaters without something to limit the temperature can cause the oil to coke in the area near the pad. (A good piston aircraft preheat setup generally also uses heaters on each cylinder as well - since they are air-cooled, heating the cylinders, rather than the block is preferred)

Note that a good oil pan heater will help start up by warming the oil promoting easier flow at startup. They are not the most quick/effective way to preheat heat an engine block, since the conduction of heat from the oil pan to the rest of the engine is a SLOW process. This is why block heaters are often used.

 

[WinterDeere]

I'm really surprised, seeing all these recommendations for 3 - 6 hours. My diesels start just fine without a block heater down below 30F. When we get below 20F, and especially below 10F, then I'll plug in a block heater. But just 20 minutes after plug in, the exhaust and intake manifolds are already warm to the touch, as is the oil pan.

I'm not going for "engine operating temperature" warm, with a block heater. But the block is already way warmer after just 20 minutes on the heater, than it would be at the 40F outdoor temperatures at which I start the engine every day without a heater. I don't see any point in running the thing longer than that, or having to plan what time I'll starting the damn thing, 3 or more hours in advance.

I don't even remember the wattage of my block heaters anymore, they're the Deere OEM units on each of my tractors, but I think they're all something like 400-450 watts. If you have a smaller heater on a larger engine, then your warm-up time is going to be longer, but I'd argue your heater is undersized for the application if it requires anything measured in "hours". I've never had any trouble starting any tractor down to -5F after 20-30 minutes on the block heater.

 

[John_Mc]

I'm really surprised, seeing all these recommendations for 3 - 6 hours. My diesels start just fine without a block heater down below 30F. When we get below 20F, and especially below 10F, then I'll plug in a block heater. But just 20 minutes after plug in, the exhaust and intake manifolds are already warm to the touch, as is the oil pan.

I'm not going for "engine operating temperature" warm, with a block heater. But the block is already way warmer after just 20 minutes on the heater, than it would be at the 40F outdoor temperatures at which I start the engine every day without a heater. I don't see any point in running the thing longer than that, or having to plan what time I'll starting the damn thing, 3 or more hours in advance.

I don't even remember the wattage of my block heaters anymore, they're the Deere OEM units on each of my tractors, but I think they're all something like 400-450 watts. If you have a smaller heater on a larger engine, then your warm-up time is going to be longer, but I'd argue your heater is undersized for the application if it requires anything measured in "hours". I've never had any trouble starting any tractor down to -5F after 20-30 minutes on the block heater.

The longer soak times are probably because preheating an engine is about more than just starting it. I've started my engine when it is 15˚F out without any preheating. I cycled the glow plugs twice, cranked it over, and it started up. Just because I can, doesn't make it my preference.