Engine Block Heater

7261 Views 7 Replies 6 Participants Last post by skibum, Mar 14, 2008

Steel Blue X

Discussion Starter · Nov 6, 2007

Can anyone tell me if it is ok or advisable to leave the block heater plugged in all night. Should I set it up on a timer?

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Most block heaters don't really put out a lot of heat, and generally just enough to keep from freezing. Additionally most also have a temperature sensor that shuts on and off the heater as need be. I would think plugging it in at night then unplugging it in the morning should be adequate and probably better than having a timer turn it on at 3am and have the heater work overtime to try to get the block to above freezing temps.

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JeepMammouth

· #3 · Nov 20, 2007

Steel Blue X said:
Can anyone tell me if it is ok or advisable to leave the block heater plugged in all night. Should I set it up on a timer?

My experience with block heater is that if you get your vehicle 'use to it' you will be stuck doing it. YMV but that seems to be also the opinion of my dealer who told me exactly that when I recently bought my JK Rubicon.

I use the heater only for -30 or lower forecasted nights

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bldrnr2000

· #4 · Mar 14, 2008

I am a pilot and used to own a Maule which is considered a north country bush plane. Engine block heaters are a huge topics in aviation because the engines are aluminum with steel cylinders. (The expansion coefficients are different for the different metals.) I never started my Maule below freezing temps without preheat because at those temperatures the bearings have no clearance and lubrication is terrible. Back on subject: leaving heaters on tends to heat the oil and tends to promote evaporation of moisture that normally ends up in the oil as a result of combustion. In aviation it is generally felt that leaving the preheat on longer than needed just encourages rust inside the engine.

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LSM

· #5 · Mar 14, 2008

Up here in Western Canada, we need block heaters during the winter. I generally only plug mine in when it gets below -16 C or 3 F. According to what I have read and from personal experience you only need to plug it in for about 3 hours. Before I had a timer, I used to leave the block heater plugged in all night. My other vehicle has 200,000 + on it and I have not experienced any engine issues... yet.

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skibum

· #6 · Mar 14, 2008

bldrnr2000 said:
I am a pilot and used to own a Maule which is considered a north country bush plane. Engine block heaters are a huge topics in aviation because the engines are aluminum with steel cylinders. (The expansion coefficients are different for the different metals.) I never started my Maule below freezing temps without preheat because at those temperatures the bearings have no clearance and lubrication is terrible. Back on subject: leaving heaters on tends to heat the oil and tends to promote evaporation of moisture that normally ends up in the oil as a result of combustion. In aviation it is generally felt that leaving the preheat on longer than needed just encourages rust inside the engine.

X2. I'm also a pilot and have had this discussion with the co-owners of our Grumman. We use the block heater as little as possible and I don't have one on my Jeep at all. BTW, why would you ever get rid of a Maule? If I had one of those, I'd have it forever. It's kind of like a flying Jeep.

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bldrnr2000

· #7 · Mar 14, 2008

I ordered my JK with an engine block heater. Used with a timer I believe it is better than no preheat at low temperatures. Having said that I believe road vehicles have engines with good clearances even in low temperatures and oiling happens faster even with cold oil. Aircraft engines are engineered with a lot of compromises to maximize reliability and minimize weight. Oiling is not so good. I always would pull the prop through on my IO540 to preoil it before cranking it. BTW the main reason I got the Jeep is exactly because I miss my Maule. I used to land it on frozen lakes, peoples farms...I could take off in 250 feet and practically land cross ways on a runway. The other guys could only look at me the way non Jeep owners look at Jeeps. They just couldn't believe a plane could do that. My JK gives me my Maule fix at a fraction of the cost.

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