Frozen car locks... Idea

Having struggled to get in to Fender several times this month due to the frost over night, I have been looking for and thinking about solutions.

I thought about bubble wrapping the lock and handle but came up with a better idea using foam matting.

I tried it last night and despite temperatures of minus 3C I was able to get in to Fender this morning. The lock was still initially stiff but not solid. It's only been one night so I'm not claiming this problem is solved but it's enough progress to be worth typing up these notes.

Many people on Land Rover forums recommend ACF-50. Spray that in the lock barrel, in the lock mechanism and also on all the connecting rods. It's a bit like WD40 in that it replaces the water and therefore prevents ice forming. Apparently ACF-50 penetrates better and lasts longer.

Most also recommend silicone spray on the rubber door seals to stop them freezing shut.

I have some ACF-50 on order to try and already have some silicone spray.

Before I do that I am trying out my door lock insulators. They just hang over the driver's door handle at night.

I've measured and designed them to fit both Defender and Discovery 2 door handles. They are symmetrical so they can be used on the passenger doors as well.

I happened to have some interlocking foam mats handy. They are about 10mm thick. The foam is easy to form. Just heat it up with a heat gun along the length of the curve. Bend and hold it in place. It took about 4 heating's to get to the full bend I needed.

The foam always springs back a bit so it is necessary to bend it more than double to get a parallel 'U' shape. I used a metal bar as the former and a box full of tools to weigh it down.

The final measurements were 270mm wide by 280mm long. That was then cut to form the tab. The tab is 120mm long and 90mm wide with 90mm wide shoulders each side.

I deliberately wanted some of the foam to curve over the top of the handle, specifically to cover as much of the lock barrel as possible.

With hindsight it would have been easier to bend if I had left it as a rectangle and bent that double. Then afterwards cut out the corners so it fits the door handle. That would have formed a tighter curve at each end.

I need a few more frozen nights to know if this is a good solution or not.

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Update: Second frozen night
The temperature in the morning was about minus 4C. Frost all over the car. The lock was easy to open. Still a bit stiff but barely any effort to unlock.

It's not all good news. I have found a flaw in the construction.

I have been using this on Junior (Jr), our Discovery 2 as well as Fender our Defender. While I'm driving I have left it in the passenger foot well. Unfortunately, for this design, the heaters work very well in Jr and the temperature is enough to slightly unfurl the tight curve of the insulator.

I will have to re-think the construction. Probably just a wire tie loop to hold both sides together.

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Update: Third frozen night

We have decided that the insulation does work. At least down to -4C.

It is obvious on Jr that the area under the foam is protected more from the frost.

The ACF-50 arrived yesterday so I decanted some in to a small bottle with a needle nose dropper and used that to inject the ACF-50 in to the barrel of the lock. Hopefully that plus the insulation will sort out the frozen locks.

I'll also spray ACF-50 inside the doors when I have time to take the door cards off.

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Update: Minus 6C

Another cold morning and yet again the door opens.

Frozen drinks

This time the lock barrel had been treated with ACF-50 and my home made insulator had been on the handle all night. That combination has worked down to -6C.