Rat's nest under the hood

My old Caravan has been parked (without a battery and not run) for a couple years in a woodsy part of my property. The plan was to buy a new battery for my other car and put the older battery in the Caravan so I could at least move it as needed. I laughed, then groaned, when I opened the hood ready to install the battery - there was a massive pile of sticks on top of the engine, a genuine rat’s nest. Thankfully, nobody was home.

It was easy enough to remove 3/4 of the mess, that filled a medium size garbage can. But the remainder is scattered everywhere, including underneath what I guess is called the intake manifold. It’s the V-6 3.3 liter engine.

The engine started with a little prodding, but I didn’t run it long for fear of something getting hot enough to ignite.

So how do I safely remove the woody material which is out of reach? I’m hesitant to use compressed air, thinking it might result in some stuff getting buried deeper. Vacuuming seems more logical - but I’ve heard often about the danger of using a shop vac around gasoline.

Can a vacuum be used safely in a case like this if the engine hasn’t run for a few days - meaning that any stray fumes would be long since evaporated and dissipated?

I’m risk averse, but also lazy, so I’m hoping for an easier solution than pulling pieces off the top of the engine. Is the vacuum safe… or suicidal?


I can’t imagine a spark from a shop vac being worse than the sparks already being created in the engine bay. Gas fumes are reasonably contained so vacuum away and have fun. I’d be more concerned about mouse urine though so glove up and maybe wear a mask and wash thoroughly afterwards. Rodents are not your friends.

+1, but I would advise that the OP should definitely wear a surgical mask. In addition to the fairly-common Leptospirosis, it is possible to contract the deadly Hantavirus from mouse urine and feces.

1 Like

Yup, I understood the rodent issues, less certain about the vacuum + fuel hazard.

Turn it upside down and shake it.

I’ve been considering that. Can you stop by with some pals to help?

1 Like

Don’t people wash their engines? Isn’t there a detergent for that? Spray a bunch, then hose it off?

I’d pick as much as I could off by hand, then take the truck to one of those diy’er car washes that use a pressurized wand, and clean the rest of it off that way. Block off the air intake and cover the distributor and coil(s) with plastic first, so they don’t get overly wet. Exactly what you need to protect from the water spray depends on how your engine is configured. If it will start, idle the engine for a few minutes to evaporate away any remaining water. After it cools down I’d remove the parts of the air intake path (including the air filter box) that’s easily removed and clean that all out by hand. New air filter, replace what you removed, done with the external engine cleaning part. I expect you’ll have a bunch more stuff to do before having a well running machine again.

Thanks, but there are several reasons why that’s not a solution:

  1. I don’t want to get the engine hot - fire danger
  2. The van is on non-op status, can’t drive it on the street
  3. Applying water is a bad idea: Most of the debris is larger woody pieces - twigs etc - which would likely swell up and remain stuck where they are.
  4. Whatever did move could easily get trapped on something below, rather than fall off.

Instead, I’ll remove as much as possible with the shop vac, then carefully apply compressed air with a long stiff tube I’ve attached to an air nozzle. I was just hesitant to try the shop vac without other opinions on potential safety issues.

Shop vac away, no worries. You’d need copius vapors to have any issue. That’s almost non existent risk, especially outside. I vacuum up acorns and nesting materials fairly often from top of engines and in the bay area. No big deal. Use a smaller hose and a rag, to stuff up the gap at the end of the shop vac hose, to reach the smaller areas.

Thanks @TwinTurbo.

That was just what I was thinking - there’s very little fuel vapor detectable under the hood. Different in carbureted engines I guess? I was hoping to get input from someone who has done what I was asking about, grateful for your reply.

I’ll use the precautions suggested above and proceed. Case closed. Thanks all…

1 Like

You can use the shop vac in the “blow” mode to blow a lot of that stuff away too. Experiment w/the different attachments to see which one does the best job. Be sure to use a good breathing filter due to the possibility of unhealthy stuff in the material.