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Oil Pan Heater When not Cold?

Is it worth using an oil pan heater to heat up the oil in say for example the motor or transmission even when it’s not cold outside? I live in USA, New England area. It can get pretty cold during winters, single digits, and below zero even at times. But I’m saying for general every day use, even when it’s not cold, is there a benefit of heating up the oil to operating temperature before you start the car? I really don’t see any reason why there wouldn’t be a benefit in doing this. If the oil is at operating temperature when you start the car, then the oil will be more viscous, making that cold start, a start with operating temperature oil.

If that is what you want to do then go right ahead . For the extreme cold if it is convenient to plug in sure, the rest of the time why bother .

Edit : Actually the oil pan heater might even make the magnets you want to put on the outside of the oil pan work better. :wink:


It is a waste of energy, there isn’t enough electric power available for everyone in New England to heat their engines 23 hours a day.

Only if he uses stainless steel bolts to attach his oil pan, We don’t want those bolts to get rusty :smile:

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I don’t think there would be much benefit to an oil pan heater, particularly with today’s 0W-20 oils specified by many of today’s cars. In fact, I was able to start my 1971 Ford Maverick when it sat outdoors in minus 22 degree weather and the crankcase contained 10W-40 oil. I didn’t have an oil pan or engine block heater. There was no way to get electrical power to the car. I didn’t cm use starting fluid. I just got in and ran the starter. It turned over slowly, but it started almost instantly. I let it warm up for five minutes before I took off.

He can always get an extension cord that reaches to Nevada :slight_smile:

Not sure why you are spending so much time dreaming up these strange automotive subjects that you obviously have been lately, based upon your recent posts, but I suppose there are worse ways to spend ones time. Like determining that something is not needed and yet doing it anyway is one example.

After reading your most recent post, there is a real world device that comes to mind and that would be The Engine Pre-Oiler…the difference being that the Oiler actually has a great many benefits and was used to reduce wear on very expensive engines like those in aircraft etc. They worked very well to keep the metal happy in those crucial moments when there was little to no oil pressure, pre and post engine start.

If I had to choose which one to heat…the oil or, the coolant… I would go with the coolant. Heating the oil and or the coolant would basically do the same thing sooner or later. but heating the coolant would do the job faster and more thoroughly than going with the heating of the engine oil…for obvious reasons.

Definitely skip heating anything until it gets cold enough to have to do so…otherwise its a waste of time and energy.


I have used block heaters, way better than an oil pan heater, usually 15 degrees and below.

The only time you ever need a heater is if it is way below zero-like ten or twenty. If you have fuel injection and use the proper weight oil, just not needed. I haven’t used a block heater in Minnesota for years. Another thing is some of the oil pans now are aluminum so magnets don’t stick. We had a lady at work years ago that complained someone stole her magnetic heater in the parking garage. Nope. It fell off somewhere between home and work.

One idea, do the experiment. Prepare two samples in clear glass heat-safe test jars & compare the apparent viscosity of the oil at 70 degrees vs 160 degrees. Post your photos as we’re interested in seeing the results.

oil gets less viscous as it heats. The viscosity index improvers in multi grade oils lessen the thinning effect but never eliminate or reverse it.

Multi-viscosity oil has a winter weight.

That’s the first number with the W after it.

That means the oil will flow at that winter weight from 0 degrees up to 210 degrees.

Once the oil temperature exceeds 210 degrees, the oil begins to thicken. and that’s the viscosity of the oil represented by the second number on the bottle.

So George’s experiment is moot.


Not based on the article you posted nor anything I’ve ever read. Looking at a viscosity vs temp graph, oil just keeps getting thinner with increasing temperature.

This is a more comprehensive reference article. Note graph #3 and the paragraph immediately above it.


Exactly. The way to think about it is that, viscosity improvers allow the oil to thin less (than oils without VIs) with increasing temperature. It never gets thicker with increasing temperature…

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Why not put the car on jack stands and let it idle in gear when not in use? That way all the fluids are kept warm. You could hook up a servo to periodically operate the brake pedal to keep that fluid going too.

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If you lived in the White Mountains near the Canadian Boarder, then Maybe, but only those few days where it gets cold enough. New England covers a lot of territory. I live in Southern NH and a heater is completely unnecessary. I have seen extremely cold mornings in the White Mountains (-30), but those days are extremely rare. A good synthetic oil (0W-20) will flow even at those temperatures.