This may be a dumb question, but I have been thinking about taking off the engine cover of my 2001 LS 430. Will it cause any issues if I take it off? How do I take it off correctly without messing anything up? How do I put it back on because I think it isnt on there all the way (#2) I want to take it off because 1. It needs to be cleaned (caked dirt) 2. When accelerating to about 2500 to 3000 rpm I can hear the air coming out from under the cover kinda sounds like a steam pot. - The noise isnt really an issue nor is it loud. You only really notice it if no one is talking and no music is playing in the car.
I mainly want to take it off because I think it will be easier the clean that way instead of leaning over the car to clean it. I will be cleaning it with Simple Green spray unless I should use something else

 

There are two nuts on the top. Remove. Then just lift it off. There are some simple clamps that press down on the rear of the cover.

Takes about 1 minute to remove and put back on.

It just keeps dirt/dust off the engine surface. I do not think it will hurt anything to remove (any) of the covers.

 

The cover serves as a barrior to engine noise; injectors, manifold air, lifters.

If your goal is to increase noise then remove it.

 

I removed the plastic engine cover years ago on the LS430 and SC430 (have them bagged and stowed in the attic). No issues, no increased noise. My thinking is that removing the plastic cover results in lowered temps on the wiring loom, rubber hoses, and connections that were beneath the cover which appears to do very little but serve as a heat trap over the manifold. This is just my pure subjective non scientific opinion on the general uselessness of silly plastic engine covers. I could be dead wrong. They may serve some critical useful purpose (but I highly doubt it).

I clean my engine bay about once a year so any accumulating dust and dirt on and around the manifold and TB area is actually easier to see and remove without the plastic cover in place.

 

Thats a really good idea I am actually gonna remove mine also

 

Engine bay temperatures have been a bane for car designers for years. They make so many frequent changes that they have not been sufficiently able to determine the temperatures that components have been subjected to. In the mid 90's the GB proving grounds had a high end Mercedes which they found the computer had been installed in the air conditioning ductwork to keep it cool. They thought that was extravagant and had installed instrumentation trying to find out what the bay temperatures actually were. I am sure that auto engineers have learned a lot since that time. Consequently, it is my experience that we really shouldn't monkey with some things that we don't understand and assume they serve no purpose. Or, maybe I am just an old retired aerospace engineer trying to defend other engineers. Procedure at your own risk.

 

I like seeing varied opinions on questions like this. Way better for the forum in general when folks can read different views and perspectives on a particular question.

 

Not much use but dresses up the engine compartment. It's the "fancy refined" Lexus look. I found the clips on mine were squeaking so removed. I can't tell any difference in noise level. If the engine runs a little cooler that's a plus.