Run Block heater all night, or timed? - PeachParts Mercedes-Benz Forum

Feelstranger · #1 12-16-2005, 02:49 PM

Hey all, wondering if Mercedes intended (designed) the block heater to be on all the time, or intended for a timer? It is not thermostatically controlled, but the element is small so max temp is likley low...
So, what do you do?
For those with timers, how long does the heater take in single digits and below to get her warm?
Thanks!
First winter with a 300D..
Nat

Glinko · #2 12-16-2005, 02:57 PM

I left mine plugged in overnight and the engine was still sluggish to start the next morning.

I don't have any expertise in this field of query, but from personal experience, I say that it can't hurt to leave it plugged in for as long as possible.

Old300D · #3 12-16-2005, 03:14 PM

I time mine to run 4-5 hours before I leave, and I can't tell any difference in starting from leaving it on all night.

rwthomas1 · #4 12-16-2005, 03:15 PM

This is a "that depends" question. My MB is garaged but the work truck is outside in an instant garage so it is plugged in. I plug the truck in once the temps start dipping below 40*F. I have a timer that switches on at 3am and the engine is warm to the touch, maybe 70* by 7am. Leaving the heater on longer may or may not increase the engine temperature. Do some experimenting. I would guess 2 hours minimum but 4 hours should do the trick. Engine heaters are great. They cost pennies to run and you will enjoy summer starting ease with heat out the vents much faster. Most engine heaters are 600+watts so make sure when you buy a timer that it can handle the load. 1000watt timers are @$10 at hardware stores. RT

Douglas.Sherida · #5 12-16-2005, 03:26 PM

Last year I ran it on a timer for 3-4 hours before startup. It would get the block up to about body temp, even in single digits (farenheit). There are distinct advantages to running the block heater even if you don't need it. The the engine warms up faster (which is good for many reasons), the cabin heat comes on alot faster and I it seemed to me that the block heater tended to alleviate some of the icing up on the windsheild.

If you leave at a regular time in the morning, I'd recommend a timer.

This year I don't drive regularly during the week (commute by train) and so I haven't used the block heater at all. She (1985 300TD-T) started right up at 9 F after sitting for three days (but the cabin heat doesn't kick in for that first mile and a half).

PRCBD · #6 12-16-2005, 03:40 PM

just for fun let's figure the real cost. 1000W for 8 hours is 8kWh at ~$.08/kWh is $.64 per night or ~$20.00 per month...did I do that right? Not bad, I guess, for easy starts and less wear on battery.

boneheaddoctor · #7 12-16-2005, 03:53 PM

I'm going to run mine on a timer....so I get heat quick......I don't need or want to pay to heat it all night long...

jaoneill · #8 12-16-2005, 03:59 PM

Timing depends on the ambient temp and size of the heater.

When temps here drop into the -20 to -40 (f) range, I plug in the 190D (MB block heater) when I pull into the [unheated] garage; it is always plugged in unless it is on the road. If the temps are moderately below zero, 2-3 hours is enough for an easy "summer like" start. Zero to +30, 1-2 hours seems to be plenty. Takes a bit of experimentation.

Do a search here on block heaters for more info; there are many advantages to utilizing them to the fullest extent practical. Starting warm will save substantial wear & tear on the engine.

Good luck,
Jim

pawoSD · #9 12-16-2005, 04:07 PM

Quote:

Originally Posted by PRCBD

just for fun let's figure the real cost. 1000W for 8 hours is 8kWh at ~$.08/kWh is $.64 per night or ~$20.00 per month...did I do that right? Not bad, I guess, for easy starts and less wear on battery.

All of these heaters are 600w or less, mines only 375....a 1000 watt block heater would keep it at operating temp!

I calculated it costs us here about $0.17-0.20 per night to run it for 6-8 hours

Steve Gold · #10 12-16-2005, 04:17 PM

One of my spares cars has a block heater which i may fit just for the warmth on a cold morning and to be better for the engine. I did wonder if the USA v Europe version have different voltage ratings as all of Europe is 230V or so? and a 230 volt heater would not be so hot at 110 volts.

Steve

#11 12-16-2005, 07:19 PM

Quote:

Originally Posted by Steve Gold

One of my spares cars has a block heater which i may fit just for the warmth on a cold morning and to be better for the engine. I did wonder if the USA v Europe version have different voltage ratings as all of Europe is 230V or so? and a 230 volt heater would not be so hot at 110 volts.

Steve

I would measure the resistance across the heater (ohms) and calculate the power (watts) based on 110 volts.

Watts = (V^2)/R = 110^2/R = 12100/R(ohms)

If you get a result in the 400W range, I would say you are OK. So you are looking for about 30 ohms, or so.

Regarding the time to run the block heater, I have found my call starts very easily after 2-3 hours. I don't have a timer, so if I want it ready to go in the morning I plug it in before bed. Actually, I don't bother unless the overnight temperature is going to be below +10 F or so.

ConnClark · #12 12-16-2005, 08:09 PM

When I had my 79 with a block heater, 1 hour made a big difference. Sure another hour or two would have been better, but I didn't have a timer that could handle the wattage so I would have had to get up sooner

.

I don't think I have a heater in my 85. I may add one after I get some other problems out of the way (hernia surgery)

sailor15015 · #13 12-16-2005, 08:52 PM

I have a block heater on my wrecked '85 but it still started without it one morning when it got down to about 8 degrees F and I forgot to plug it in. I put it on a timer to come on at about three or four in the morning and I leave about seven thirty. Leaving it on overnight just made the top of the valve cover really warm to the touch. I didn't notice any difference in cranking times with or without but my brother told me his wouldn't start one morning so I think I'm going to take the heater off of my car and put it on my brother's when I get it (Monday or Tuesday!!!

) because his doesn't have one. Is this an ok thing to do?

#14 12-16-2005, 08:59 PM

Quote:

Originally Posted by sailor15015

I think I'm going to take the heater off of my car and put it on my brother's when I get it (Monday or Tuesday!!!

) because his doesn't have one. Is this an ok thing to do?

It sure sounds like a good idea, but getting the plug out sounds like a real PITA on the 617. Search on the other recent block heater threads.

waybomb · #15 12-16-2005, 09:36 PM

I installed a 1500 watt Zero-Start between the block drain and the head. I bought a Intermatic 40 amp single pole 110vac timer on eBay for 20 bucks. I have the timer set for 1.25 hours before I go out to the car in the am.

That with the 80 watt battery heater (leave on all night) has the 23 year old diesel starting at below -5f with no problem, and lots of heat when I start it up too.