Oil Pan Heater Pad

How to keep the Cessna 170 flying and airworthy.

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reecewallace
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Joined: Tue Jan 05, 2021 1:34 am

Oil Pan Heater Pad

Post by reecewallace »

I live in Canada, it can get cold. My hangar isn't heated and I'd like a way to keep the oil warm throughout the winter so I can just fire up and go, without excessive warm up or putting a hair dryer in my cowling for hours.

Anyone have experience with these?

https://www.aircraftspruce.ca/catalog/e ... kkey=26532

Thinking of sticking one of these on the oil pan of my O300. Anyone know if it's 'safe' to leave it plugged in full time throughout the winter?

Also, anyone know which exact model to purchase for an O300?
- Reece
1956 Cessna 170b
Nanaimo, BC Canada
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cessnut
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Re: Oil Pan Heater Pad

Post by cessnut »

I have an EZ Heat pad on an O-200 kidney tank in a 150. It does a nice job of heating the oil and the engine with a cowl blanket here in MN. I haven't considered leaving it plugged in, because of the electric cost, and the fear of condensation in the engine.
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brianm
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Re: Oil Pan Heater Pad

Post by brianm »

One engine heater manufacturer that I talked to told me, off the record, that he leaves his heater on all winter with a blanket over the cowling. His personal opinion (the company takes no official position for fear of liability) is that it's heating and cooling cycles that cause condensation buildup. I know several other people who subscribe to that philosophy and have had zero trouble over many years.

As far as cost goes, a 300 watt heater would cost about $30/month at my current electric rates, assuming it ran flat-out all month. Thermostatically controlled heaters should use quite a bit less than that once the engine is up to temperature.
Brian M
N2669V - '48
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cessnut
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Re: Oil Pan Heater Pad

Post by cessnut »

30 bucks is 30 bucks and I don't fly enough in the winter to need it warm all the time. The EZ Heat warms it up nicely in a few hours. As for condensation, I can't speak authoritatively but I know that I haven't had any issues leaving it cold . I do try to be sure to fly after a preheat.
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DaveF
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Re: Oil Pan Heater Pad

Post by DaveF »

That's the sump heater I have on my Lycoming O-360. Works great. I run it for one to four hours before flying in cold weather.
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GAHorn
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Re: Oil Pan Heater Pad

Post by GAHorn »

reecewallace wrote:I live in Canada, it can get cold. My hangar isn't heated and I'd like a way to keep the oil warm throughout the winter so I can just fire up and go, without excessive warm up or putting a hair dryer in my cowling for hours.

Anyone have experience with these?

https://www.aircraftspruce.ca/catalog/e ... kkey=26532

Thinking of sticking one of these on the oil pan of my O300. Anyone know if it's 'safe' to leave it plugged in full time throughout the winter?

Also, anyone know which exact model to purchase for an O300?
I believe that continuous heating is frowned upon by engine mfr’rs as being conducive to accelerated corrosion issues.
And I don’t like heating pads because they 1) also reduce heat-shedding in-flight, and 2) hide corrosion evidence (and our oil sumps are subject to this., 3) oil sump heaters heat the oil…and by convection/radiation warm the rest of the engine…but do very little to heat the “hot section” which suffers higher wear during cold-starts. (The cold piston, rings, valves, rockers, bushings, etc are the high wear areas in a cold start..not a crankshaft or cam/tappets which are usually filled with oil anyway (despite being cold oil…which acts like grease and keeps plain bearings lubricated until replenished by the oil pump.) At least that’s the way my imagination works.


I’d ask myself, “How often do I need to spontaneously go fly my airplane?” Don’t you actually have at least an hour or more to prepare for your flights?
Isn’t that sufficient for a hot-air heater to work?

If you have electricity available to run a heating pad…. then why not obtain a hot-air heater (even a milk-house heater or small bathroom heater that gently blows hot air) which over an hour or two will heat the entire engine compartment? Place that warm-air heater on the ground and direct the warm air up into the lower cowling-exit with duct-work. That warm air will warm the oil sump, and the warm air will rise and pass thru the cylinder-fins/baffles and warm the cylinders, valves, and pistons/rings/etc. as well.) Those cylinder fins work both-ways…they’ll transmit heat TO the cylinder as well as away from it. The pushrod-tubes, cylinder base, walls, head, rocker-box covers, carburetor..…firewall items, voltage regulator, gascolator, oil-pressure sense-line formerly full of congealed oil, etc. All will receive warm air…not just the bottom of the oil sump.

I have a 4-ft long, 8” corrugated aluminum duct (($20, intended for HVAC duct) which I have pop-rivetted onto the exit-cone of a $19 milk-house heater that in 2-4 hrs (sometimes I put it on a common timer to begin heating in advance of tomorrow mornings flight, for example)…. it heats the entire engine compartment… engine, generator, starter and accessories…not just the oil sump….

No condensation-creating heat/cool cycles. No continuous accelerated/elevated temperature issues. No logbook approval basis necessary for modifying my airplane.
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'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons. ;)
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mit
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Re: Oil Pan Heater Pad

Post by mit »

Herman Nelsons work great!
Tim
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dstates
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Re: Oil Pan Heater Pad

Post by dstates »

One advantage to to a sump heating pad or cylinder wall heating bands like the Reiff option is that they go with you. If you end up tied down outside overnight, many times you can get close enough to an electrical outlet to borrow an extension cord from the FBO (or take one with you).

https://www.reiffpreheat.com/product.htm
There is a picture at the bottom of this page that shows the bands that go around the cylinder walls. Not a cheap installation, but if you live in a cold climate and want to fly often, it would be something to consider.
N1235D - 1951 170A - SN: 20118
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dstates
Posts: 477
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Re: Oil Pan Heater Pad

Post by dstates »

Here is another option that you can easily take with you:
https://www.aircraftheaters.com/

Here are a few videos of a guy in central Iowa who has done the milkhouse heater and these twin-hornet heaters and some cool infrared images of them at work.
https://www.youtube.com/playlist?list=P ... UZKfT9JhMN
Last edited by dstates on Fri Feb 17, 2023 1:19 pm, edited 1 time in total.
N1235D - 1951 170A - SN: 20118
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GAHorn
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Re: Oil Pan Heater Pad

Post by GAHorn »

The prop is a huge heat sink/dissipator and some thin-sheet foam insulation folded into a sort of flat “sock” and slipped over the blades will assist in retaining heat within the engine and assist the cranks’ heat retention also. A blanket (or sleeping bag which you keep in the bag compartment as a hedge against an outback forced-landing) thrown over the cowl certainly improves efficiency.

Personally, when it’s been below 30-degrees, I’ve used only the milk house heater/duct system. If I’ve got an early-AM departure, I plug it in the nite before….or using a timer set it for about 4 hrs prior to deprture. The entire engine , fuel system fwd of the firewall, and firewall/cockpit instruments are heated when the cabin heat knob is also deployed… and my high-tech heat-sensor system…(my hand)…can FEEL everything is warm. My hand is around 95-degrees or warmer and so if something feels warm to my hand…. it’s warm enough to start/fly… IMO.

Beware that overpriming an engine only sprays fuel into the intake manifold. This “excess fuel” will assist in a start…BUT…it also drains down into the carb throat and can drain down into the airbox and onto the ground. Any ignition-source can create an induction-fire. KEEP CRANKING to “suck” that fire up into the induction/cylinders and you should be fine. However, and intake fire can damage air filters creating trash which can be sucked into the engine …so a close inspection (remove air filter/inspect behind the filter-housing. Add this procedure to your regular winter-time pre and post flight inspections if you suspect overpriming.)

Hope this helps.
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons. ;)
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cessnut
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Re: Oil Pan Heater Pad

Post by cessnut »

Battery maintenance is also important in cold weather to ensure adequate cranking speed and be able to suck in an intake fire.
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mit
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Re: Oil Pan Heater Pad

Post by mit »

Tim
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