Alright before I ask the question I'd like to give a brief summary on the situation of my FC. I purchased it a few months ago and recently discovered that the previous owner had overheated the engine, so it now leaks coolant into the engine (oil can also be seen in the coolant tank). The leak isn't big but I'm deffinitely gonna need a new engine soon as a scrounge up the cash. Recently I was messing around with the air/filter box and I removed the lid and took it around the block to see if I noticed a difference in performance because of the increased airflow. Not suprisingly not only did it sound much better but it gave me much better throttle response at all RPM's.

So the question is, would it be be harmful to the car to leave the airbox lid off? I see no real difference between the exposed filter and an intake besides the cone filter.

 

Also, I can't find a reason why it would matter that the lid was off other than exposure to water, and I cant see how that would get even close to it unless I drove into a lake.

 

One thing the lid does is clamp the air filter down. If you plan on keeping the lid off, just cut the top off, and use the edge as a filter clamp. Better yet, get one of those cheap 3" air filter and adapter kits off of ebay. They'll give you a bit better air flow than the box with a cut lid. Yoy can always upgrade to a higher quality filter later.

 

Your big issue is the coolant leak.
If you don't deal with it first, nothing else will matter.

I have had this happen, and was able to patch it with radiator stop leak.
I caught it early, before there was too much erosion of the O-ring seals.
The short version:
Good coolant flush, add half the stop leak, idle warm up to full temp, shut off & cool down cold, (repeat)
Do a search under "block weld".
Many have had good luck with that product & there is a good write up on the forum using it.
No guaranty, but it can’t hurt to try..

 

Thanks for the info that helps alot, I was under the impression that coolant leaks were pretty much impossible to fix but I'll check it out ASAP you may have saved my engine.

 

cut out the center of the lid. the part with the Mazda sticker on it.

 

I cut the lid on my car and put in a k&N filter it feels way better than the cone filter I had before.