1997 Mazda MX-5 Miata: Too Hot
October 19, 2012
I hate driving our longterm 1997 Mazda MX-5 Miata when it's hot outside. The reason? It's even hotter inside the car.
I've noticed this in every first-gen Miata I've ever driven for any prolonged period of time -- the cabin gets nasty hot. Recently we experienced some unseasonally hot weather here in SoCal, and driving Project Miata around in it reminded me how I'd rather park this little green tictac during hot weather than deal with its steamy cabin.
Why is this? Well, first, the a/c in first-gen Miatas is kinda weak. Despite having only a tiny cabin volume to cool, the stock a/c just can't keep up with summer-like California weather. It blows cold air, just not enough of it.
But tepid aircon is not the root issue. The main problem is that there's another heat source besides the pavement and the ambient air that's pummeling the cabin with calories -- the exhaust.
The exhaust in a Miata runs down the driver's side of the transmission tunnel. Due to proximity and insufficient shielding, heat from the exhaust and catalytic converter simply bakes the entire transmission tunnel, and then the tunnel radiates like a giant hot plate into the cabin. Just hover your hand over the carpet on the trans tunnel and you can feel the heat! Don't put anything that's temperature-sensitive into the console cupholder -- it'll melt.
This radiant exhaust heat also takes its toll on the rubber boots surrounding the shifter, which lead a relatively short life in Miatas as a result.
Want swamp ass? Sit in a Miata in Los Angeles rush hour traffic during August. And were the hardtop not in place, it'd be even worse -- the last thing you want in a California heatwave at midday is the sun screaming down on you.
Next time this thing is on our Rotary Lift, I'm putting some heat shields in the trans tunnel.
Jason Kavanagh, Engineering Editor