Ramifications of removing engine firewall insulation?

So I have been battling mice for years now, in my 'Taco. Have multiple posts elsewhere on this board; with the issue; the trials and tribulations of ALL preventive measures that one can take against them.

I'm getting ready to remove my plenum, intake and fuel rails soon, to replace the damaged knock sensor wiring harness underneath all of that.

In doing so, I am contemplating the removal of the fabric firewall insulation. This one type of material within my engine compartment; is the catalyst for mice to mine from, and they use the material to attempt nest building under my intake.

I have tried all sorts of repellents on it and either the mice get used to the repellents or they simply don't give a fuck.

Will I have heat issues within the cab if I remove the top half off the firewall insulation? Increased noise within the cab?

You can see where they have been mining the insulation over the years. The black (the original color) is now yellow.

 

Going to be honest, that insulation look untouched by mice. They usually dont just skin the top layer off when building a nest, they will chew holes and big chunks out.

That looks more like its just fading or has been washed off by a hose

 

Absolutely not brother. This has been going on for years with my ‘Taco and the field mice. Take particular attention and zoom in to look at the firewall insulation in the first picture posted. You can see how it has been clawed away.

if you peel away the outer material of the insulation, it is yellow underneath it. The outer portion is easily scraped away and stuffed up under the intake by mice.

 

rather than removing it (it looks like it might still be effective), how about covering it with something mice can't get thru, like metal mesh shaped with aviation shears and some (self tapping?) screws to fasten it to the bulkhead?

 

The insulation is there for heat and sound. Probably nothing will happen other than the cab will be hotter in the summer and a bit noisier.

 

It will make it hotter for sure. I have some missing insulation on the firewall of my 4Runner and I can definitely feel heat from engine inside cab.

 

My buddy is a farmer and had a similar issue with his truck, I helped him dig nests out of his engine bay twice. The mice were using the insolation as nest material. He masked off everthing he could and sprayed the insulation with black engine block paint to make a hard outside layer for the insulation that the mice either couldn't get through or just ignored. The engine paint can take the heat but be prepaired you must do several 6+ thin coats before the any thicker final coats can be done. Also the insulation will suck up a lot of paint so it is important to build those thin top layers so they don't soak in and just waist paint.

 

Kill one of the mice and hang it in your engine bay as a warning to the others should they want to trespass.

 

I sprayed it with cosmolene rp342 and allot of the underhood wires, none of the ones on the emgine though. I know people balk at owls but in winter i keep one within 10 feet of the truck. I move the position daily as well. GL

 

I would hang mothballs. Ok it’s an old one but when storing a truck/car for the winter I’d put a bunch under the vehicle a few in the engine bay. Never had an issue

 

Little bastards! I had the same thing happen on the passenger side, above the ABS unit.

Interesting tip…

But I like this one better!