Our Diesel Heater Died at Dawn in Central Otago. The Fix Was One Bolt I Could See and Could Not Turn.
Our Diesel Heater Died at Dawn in Central Otago. The Fix Was One Bolt I Could See and Could Not Turn.
July 2026 · 8 min read
First light out past Naseby, well below freezing, and a bolt I could touch and could not turn.
If you own a motorhome, a caravan or a house bus, there is a bolt on it right now that you can see but cannot turn. You do not know about it yet.
But the first time your diesel heater cuts out on a freezing night, or a levelling jack seizes solid, or a leaf-spring bolt shakes loose on a metal road a long way from the nearest town, you will find it. And you will find out that no ratchet, no flex-head, and no wobble socket in your locker can reach it.
I know, because I spent a night on the frozen gravel of Central Otago proving it.
When something lets go on a rig, it is not a camper. It is your house.
My name is Graeme. I am sixty-four, my wife Robyn is sixty-one, and I spent thirty-two years as a sparky around the Taranaki gas fields. We sold the house in New Plymouth, bought a motorhome, and every winter we point it south to see the country we were always too busy to look at. It is the life the brochures sell. Most days it earns the brochure.
This winter we crossed on the ferry to Picton and worked our way down into Central Otago, freedom camping out past Naseby in the Maniototo. The first hard frost, the diesel heater fired up, ran a minute, and cut out. Out there off-grid on the solar and the lithium, that heater is the heat, and on a Central Otago night that drops to minus six it is not a comfort. It is the difference between a good night and a dangerous one.
I have turned a spanner my whole life, so I found the fault in ten minutes. Carbon on the glow plug and the atomiser mesh, tucked down in a storage locker with the body boxed in and fifty millimetres of room around it. I could see the plug. I could get a finger on it. But there was no way on earth to swing a socket or a spanner on it in that space.
Every tool in the locker. Here is what each one did.
- Quarter-inch ratchet. The handle fouled the locker wall before the socket would seat.
- Stubby ratchet. About eight degrees of swing on a plug that needed a good half-turn.
- Flex-head ratchet. Bent in, seated, then folded the second I loaded it. I skinned my knuckles on the frame.
- Universal joint on an extension. Bled the torque off at the angle and cammed off the plug every time.
- Wobble socket. All angle and no torque, which is exactly backward from what that plug needed.
The nearest shop: a fortnight out, a hundred and forty an hour, and a van that could not get up the valley
I rang the nearest place that would look at a European heater. A fortnight out, deep in the season. A mobile bloke wanted a hundred and forty dollars an hour plus a call-out just to drive up the valley to us, if he could get a van up the metal road at all. There are barely a handful of qualified RV techs in the whole South Island, and most are a long way from where you break down. For a bolt I could touch with one finger.
I crawled out and sat against the front tyre. Robyn brought me a cup of tea and said we would sort it, the way she has every time this trip has thrown something at us. Sitting on that frozen gravel with blood on my knuckles, I was not so sure.
Head torch on, on my knees on the frozen gravel, fighting a plug I could touch and could not turn.
Then a retired diesel mechanic wandered over from a few vans down
The next morning a fellow named Bruce wandered over. Seventy-four. Forty years a diesel mechanic before he hung it up, ten years full-timing in an old Kea with his wife, fixes everything he owns. He had a look at the heater, a look at the plug up in that gap, and nodded the way an old hand nods at a story he has heard a hundred times.
He came back with a solid steel bar about the length of your forearm, square drives on both ends, a fixed bend in the middle. He had me press my thumb inside the drive end. Something moved. A roller chain, running the length of a sealed steel housing.
“The chain takes the bend for you.”
The body holds the shape and the chain carries the torque dead square to the socket, no matter what you put on the handle. Bruce told me he has set more heater plugs, levelling jacks and spring bolts with a bar like this than he can count. Not one rounded. Not one rig sent to a shop.
The sealed chain is the trick
A roller chain inside the steel body carries torque around the bend, so it never folds like a flex-head or walks like a u-joint.
Fits the fifty-millimetre gap
A slim flat bar slides into the boxed-in locker or up under the chassis where no ratchet can swing.
Your own sockets
Square drive on both ends takes the sockets and ratchet already in your locker. No proprietary anything.
It reaches. It is honest.
This solves access to a bolt you cannot get a tool on. It is the right geometry for the gap, not a miracle for a bolt rusted to nothing.
It only comes from one place
You will not find it at Repco, at Burnsco, at Mitre 10 or Supercheap. The maker sells direct from their own site only, posted to your door anywhere in the country. That is less than one call-out from a mobile tech, and a rounding error next to a shop bill, a tow, or the weeks of winter we would have lost.
What happened next
Other owners who stopped paying for access
“The hanger bolt on my leaf spring was the one my torque wrench could never square up on, jammed in behind the tyre. This bar set it on the first try, to spec, without folding. Should have had one twenty years ago.”
“I travel on my own and do my own work. The water pump bolt was buried where I could not get a driver on it straight. Had it done before my tea was cold. Ordered one that night.”
“A levelling jack bolt behind the crossmember had me looking at a fortnight's wait in Queenstown. Turned it in the camp in ten minutes. Paid for itself five times over already.”
Bruce learned it from a fellow at an NZMCA rally. Now he keeps one spare to pass on.
Get yours before your next trip
If you live on the road, or you have a rig in the shed you need right before the season, and you have ever laid on your back under it looking up at a bolt you could see but could not turn, now you know there is something that reaches it.
Two Islands Field Notes is a reader-supported publication. This is a first-person account from a motor caravanner and reflects his personal experience. The Savary offset extension wrench is a hand tool designed to reach fasteners in tight, blind locations. It improves access to a bolt; it is not represented as a remedy for fasteners that are rusted or seized beyond normal service. Always follow proper service procedures and torque specifications. Results vary by rig and condition.
This is an advertisement and not an actual news article, blog, or consumer protection update.