Plastic Engine Covers - Remove or Leave?

[Mazda Man]

Lennie Legend’s engine is covered in plastic covers;

My question is....In order to aid airflow under the bonnet, would you remove them?  However, my simple brain is telling me:

REASONS TO LEAVE THEM ON

1. Some clever Japanese engineer designed these for the car, which presumably costs gazillions of yen to develop?  Why then take them off?
2. Perhaps they prevent heat from rising and damaging the bonnet paint?
3. Presumably they are also noise reducing so you don’t hear the engine as much?

REASONS TO REMOVE THEM

1. They trap heat underneath the bonnet.  Therefore removing them would allow quicker heat dissipation and allow cool air to circulate around the engine?
2. They could hide leaks and things?
3. They need to be cleaned all the time?

Answers on a postcard please chaps.  

[hughezee]

Will post the postcard later Geoff ?

[PTR200S]

Leave them on, 1,2 and 3 apply !!!!

Seriously unless the engine is pretty ! underneath those covers leave them to get on with the job they were designed for..!! ? 

Don't do postcards and anyway I haven't got a stamp handy ?

[Retro Rich]

My answer will go on the back of a postage stamp. Leave on, reasons 1,2 and 3. 

[Laird_Scooby]

1~ There's a good reason they're on there Geoff - Honda spent megabucks to work out why and make them as effective as possible.

2~ Being black they help dissipate heat.

3~ They're acoustic baffles as well.

In other words, Leave them on, reasons 1,2 & 3 in your first section!

Aka what the others said.

If you want to remove heat from your engine bay, a very cost effective way is to wrap the exhaust downpipes with exhaust thermal wrap. It will also make your exhaust note a little deeper and may even improve performance and/or economy. It can (under certain circumstances) also prolong the life of your engine oil but that's mainly in FWD applications where the front downpipe passes under the sump.

[Mazda Man]

Think I’ll leave them on.  When the sun is out again I’ll take them off and give them a proper clean.  Needs to get some new clips first though.  ?

[Laird_Scooby]

Sounds like a plan to me Geoff!

You'll have to get enough clips to renew all of them then? Or whip the covers off now, give them a good clean and work out how many you actually need?

[Mazda Man]

Just bought 20 of these babies, should be enough:

 

[Laird_Scooby]

As long as they're the right sort Geoff you should have enough to replace all of them so they all look bright and shiny and new.

Hope you'll be trimming the sprue from the edges of them to tidy them up a bit? All about attention to detail!

[Mazda Man]

Of course David.  My Stanley blade is at the ready.