Spring for one of these, or similar. You'll be glad you did-someday (NFI):
Rats got under the intake manifold on my mom's Lincoln, ate some of the wiring which cased a CEL ('CHT temp bad' or something and the temp gauge was dead-no way it passes smog). A quick peek with the 'scope' confirmed the issue. If you haven't tried it, pulling the intake off a modern (2000) 8-cyl car, a British engine no less, is a BIG job (including requiring at least one 'special tool'). I got the manifold off, restored the chewed-up wiring and had the manifold almost back together--something like 16 little bolts, torqued to spec--when I got the 'Oh, crap, did I reconnect the coolant pipe for the throttle body' moment. Fortunately, with the 'scope' I was able to confirm the tubing was at least connected (whether it would leak or not was TBD-it didn't).
Same car, starts leaking oil from a valve cover--did I say it's a British (Jaguar) engine?--onto an exhaust manifold so new set of gaskets (plus new coils-on-plugs needed). This valve cover is held on with what could be called 'pins;' they're two-part, with a bolt and a retaining clip and seal under it:
Of course, one of them self-destructed when I was getting the cover back on, and the retainer fell somewhere near the engine and didn't make it to the floor. This is a DOHC car, and there was a good chance the part fell either into the timing set or on the backside of the valve train. I looked off-and-on, an hour here, an hour there, for two days with the 'scope' and finally decided to trust to luck. After a nerve-wracking startup, with no crunching noises, the car ran fine, but I'll never know what happened to that piece (hopefully, it fell into a hole in the unibody).
One of these days, I may take a peek in the cavern in the frame below the intake/carburettors in my BJ8's chassis. But, for now, I treat it like a a gravesite that shouldn't be disturbed.