Rats broke my 4WD

After nearly 400 days travelling around Australia in a 4WD and Hybrid Camper, we’re getting used to things going wrong from time to time. It doesn’t make it any less frustrating in the moment though, and I was pretty annoyed to find myself pulled over on the edge of a narrow road with the bonnet up, and coolant everywhere.

Broken down on the side of the road
Not the day I had in mind

The day started like any other one would on our Big Lap of Australia; we packed up from a magic campground in Main Range National Park, and I went to climb into the drivers seat. I spot some small bits of rubber on the floor, and immediately call out “Cooper, have you been cutting rubber with your scissors?”.

I’m met with the usual scrunched up face, and a ‘no’ mumbled as his face turns away from me which leaves me wondering if I believe him or not. I hop in, and we drive off towards our next destination, without much further thought. That was hint number 1.

About 20 minutes into our drive, I decide that our wind screen is looking a bit dirty, and hit the wipers and spray to come on, but nothing happens. Hmm, that’s strange. I don’t recall it running out last time I used it. I’ll have a look when we get to camp. That was hint number 2

10 minutes away from our destination, after we’d been driving for about 50 minutes, I glance across at our Ultragauge, and see it reading 96 degrees on the coolant temperature. That’s interesting, I think; we’ve been ticking along on relatively flat ground, and it shouldn’t be much higher than 90 degrees.

We keep plodding along, and I watch the temperature climb to 100, then 102, and my gut sinks. This isn’t normal. At 106, I bail, and pull over immediately at the bottom of a big hill with the temperature just touching 108 degrees on the Ultragauge (and I notice the factory temperature gauge goes up one from the middle) as the engine goes off.

As I open the door, I know something is wrong. The dreaded smell of coolant wafts back towards me, and I hear a hissing noise coming from the engine bay. My fears are confirmed upon opening the bonnet, and seeing steam wafting out of a small hose.

Coolant sprayed everywhere
Coolant everywhere, with steam coming from the hose

I look closer, and remark ‘RATS’. Suddenly, it all clicks. There’s a big chunk out of the turbo coolant outlet hose that has sprayed coolant everywhere, along with a chunk out of the windscreen wiper suction line, and another one out of the radiator overflow hose and that’s just what I can see right now.

At this point it all sinks in. I’m incredibly grateful for it only being a small, easy to access hose, but we’re precariously on the edge of a narrow road, right near the bottom of a hill, and right now I don’t know if the heat has caused any further damage.

Oh well, what can you do? I empty our rear drawers, and pull out the bits of hose I carry as spares, hoping dearly that one is the right size. Sarah gets stuck into keeping the kids busy, and I dig through our spares. As you’d have it, one hose is bigger, and the other is smaller. I grab some tools, and remove the damaged hose, and compare it to our spares. 

Coolant hoses for our Dmax
I had a couple of hoses, but they weren’t perfect

I slide the larger hose over the barb, knowing full well it is too big, and have my suspicions confirmed. I cross my fingers, and do the same for the smaller hose, and it goes on, albeit with much more force than the OEM hose. That’ll do!

I cut it to length, find two hose clamps (as the spring style isn’t going to work on the smaller hose), and get it all fitted, and tight. Carefully removing the radiator cap, I can see its down, and get some bottled water, and turn the vehicle on.

New coolant hose installed
Luckily I had some suitable hose

I carefully tip three bottles of water into the radiator, and watch the temperature on the Ultragauge, whilst listening for any weird noises. After running the heater and getting all of the air out of the system, I put the cap back on, and move to the next hose.

Filling the radiator back up
Filling the radiator back up with water

A bit of self amalgamating tape over the radiator overflow hose, with some electrical tape over the top to be sure, and I pack it all away, hoping that we have no further issues.

Radiator overflow hose with a hole in it
They ate the radiator overflow hose too

We get water for the camper nearby, and then head to camp, with no further overheating issues, or leaks.

Later that afternoon, I have a good look around the vehicle for any further damage, and find the rats have chewed into the rubber grommet just above the accelerator peddle, which explains the rubber on the floor. Hopefully they didn’t get into anything else.

In the scheme of things, we’re lucky. We could have cooked the motor, or damaged the turbo, or been under the car trying to access something much harder to get to, but its still a pain in the bum, and something I’d rather not repeat again.

It was painful enough just replacing the hoses on our windscreen sprayers after pulling trim off, and finding that at least 800mm of it had been chomped away. I hate playing with anything on a car that clips together!

Fingers crossed there is no further damage, especially relating to the lack of coolant and excess heat!

Why do rats chew on things in the engine bay?

For some people, its a major surprise to hear that rats would even go into an engine bay and decimate things. If you’re camping in the bush though, they are everywhere, and they love to find places that they can hide in, and if there’s something to nibble on then that’s even better.

I’m told that rats will chew on things not necessarily to eat, but to keep their teeth down at a reasonable level, or they struggle to eat real food. You might think its silly for them to chew on electrical cables, or drink bottles, but its their way of keeping their teeth at a reasonable level.

Either way, I don’t want to deal with this again, so we’re going on a hunt to fix it once and for all.

Hole in the windscreen wiper line
We had dozens of holes all the way along our windscreen wiper hose too

How to stop rats getting into your engine bay

So, my thoughts are quickly directed into how I can stop these little blighters doing any further damage, ever again. We’d seen signs in different parts of Queensland, and heard terrible stories of wiring looms being eaten, hoses chomped and damage that runs into the tens of thousands of dollars, but asides from a scratch on our airbox, I’d never seen any evidence of rats on, or in our vehicles.

At Lake Tinnaroo, there’s signs up stating you should leave your bonnet open, as this stops the rats wanting to go in with it being open and less protected. Still, I don’t want to be doing this at every single camp site we go to!


A lot of people just cable tie rat baits into their engine bay, and I can see the logic, but don’t like this option. Yes, any rats in the area are likely to eat it and die, but does the bait attract them to the vehicle in the first place? 

Its days later that the rats are dead, and then you have all of the other risks, like it falling out and killing animals that it was never intended to. I’d rather avoid getting rats into my vehicle in the first place, not just kill them when they do pay a visit.

Peppermint oil

Next up, this is well spoken about, and supposedly works really well.


I was told Mothballs, or Camphor works well, and I’ve heard varying levels of success with this. A quick look online shows that the rats don’t like one of the active ingredients used in these, but surely there’s better options?

Rodent sprays

Looking online, there’s a few rodent sprays that you can purchase, but none of the auto shops I went to had any idea what I was going on about, so we might go with a generic option like Peppermint oil.

What do you use to keep rats out of your engine bay?

If you’ve got any good solutions to keeping rats out on a permanent basis, we’re all ears. I’d really like to avoid this happening again!

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  1. Hey Mark,

    Interesting, and thanks for your thoughts. Don’t you get sick of re-spraying it all the time?

    I think the bonnet up idea is good, but I’m not always keen on leaving my car exposed like that in campgrounds either!

    All the best

    All the best

  2. Rats & mice have a similar sense of smell to dogs so peppermint oil is like pepper up their nose. I mix 10 drops of peppermint oil (eBay) & water in a 500ml spray pack and spray the lot everywhere I can in the engine bay, also down low on hoses & plastic trays/parts. The smell wears off after a few days so respray as needed. If I think there’ll be rats or mice about I’ll leave the bonnet up until I go to bed to cool the motor as much as possible, only needed in winter. A pain but better than the alternative. So far so good.

  3. Hey Lee,

    I’ve heard a few things about those rat deterrents; would be keen to know how it goes for you!

    All good regarding the blog; such is life, and the show goes on!

    All the best with your trip to WA next year. Leave a comment, or shoot me a message if you want any questions answered


  4. Hi Aaron
    I’m sorry to hear about your recent rat-induced troubles. But as you said it could have been far worse.
    I know of someone who had to replace the entire wiring loom in his VW Amarok due to rat damage…not a cheap exercise!
    Lucky it happened at his home and not during a trip.
    We’ve been lucky so far but after recently finding rat droppings and some of our friend’s dog’s biscuits on top of our engine I decided to investigate preventative actions.
    I looked at all the options you mentioned in your article and settled on a 12 volt electronic ultrasonic deterrent device from eBay. Despite my scepticism I figured at just over $20 it is worth a try.
    I’m yet to install it so I can’t comment on its effectiveness.
    I’m also sorry to hear about Google’s recent changes affecting your blog.
    I enjoy reading your reviews and have followed your advice several times. Most recent was my purchase of a used 9555 iridium satellite phone for our trip to WA planned for next year.
    Good luck with your blog and keep up the good work.

  5. Hey Brian,

    You’re very welcome. Yep, not a good thought at all. I hear mechanics and auto electricians are kept busy all over the country by rats!

    All the best

  6. Hey Allan,

    Sorry to hear! They’re a bit of a nightmare. I think I’ll try the blocks. Do you have to turn the light on and off manually? I guess I could knock something up that is permanently wired in. Interesting for sure.

    Thanks for the information!

  7. Brian McMahon says:

    Hi Aaron.
    Love to see a follow up on this. A scary thought, even when our van is parked at home.

  8. Allan Bromwich says:

    Have had rat parties in the engine bay several times now, and now resort to camphor blocks on the recovery points as well as a small led light under the car which turns on and off continuously for the evening. Also lift the bonnet if i feel comfortable with the surrounds. not sure if the above do work, but have had no further parties since.