Hood insulation?
 

Does removing hood insulation reduce underhood temp or will make it worst?

I guess it depends on how sunny it is. I don't know, but that insulation is meant to act as a fire retardant in some cars. In case of an angine fire, the plastic fasteners melt, and drop the insulation. It then, at least partly, smothers the fire.

I doubt the risk would keep me from removing the insulation, if I felt that would help in whatever issue you are having, but it's better knowing all the ramifications of doing something.

It may also have an adverse affect on the paint on the hood.


YMMV

Can make the car louder too. Engine noise does go through the hood and then the windshield. Sound deadening in the hood is usually a good first step in noise reduction.

90% of the time it's sound insulation. I've seen plenty of cars with it removed for years without bothering the paint. parking it in the sun will bother the paint more. it may reduce underhood temps a little but once the engines running, there's enough airflow it won't bother it much.

My car never had any to start with...

I'm guessing it would have only a small effect on underhood temps, however, for those runs into the store, having the insulation in place may keep the engine warmer for when you restart it.

I've got a large piece of corrugated cardboard from a box covering the top and two sides of my engine to help it maintain temps.

Does it help?? maybe. I live in a 9000 DD climate and will take any advantage when it's -20F. At that temp, the hell with mileage, I just want the heater to warm up!

I do not believe it will change under hood temps. I would keep it though for fire protection and paint protection.

Is the underside open between the bumper and the front of the radiator; that could be blocked. Where is the air intake getting air; warmer air under the hood would warm quicker than a cold air intake from outside the engine bay.