Obviously there's an issue. That's what this thread is for, to fix an issue... pretty dumb comment.

Personally, I've replaced the radiator, fan, ducted the fan, thermostat, coolant... and I'm still overheating /only with the AC on/ at low speeds or at idle.

So, not sure what it is with the only ac overheating issues. Car should be cool as hell, and is fine, except the ac, so I'm watching this thread.

Reroute coming on monday to test...

While it's nice to be important, it's much more important to be nice.

Im pretty sure the compressor is causing the condesor to run hotter or is straining the water pump. Im at the point right now that im just going to pull the ac system. Im trying to get the car ready for Harris Hill in October and I would like to be able to drive to the track and daily with ac. Seeing as the track and my job is less than 5 miles away I could live without it just sucks ass when its hot out. I apreciate everyones input this whole time Thank You Fellas.

The ac is not your problem, seriously. Don't chase the wrong rabbit.

And if it's only getting bad with the AC on, just don't turn it on. No need to yank it, right?

So a little update. I yanked the AC depowered the rack and my temps stay much lower. Under hard driving I am getting up to 219 in boost back to back. Literally rompin on the car over and over. If I drive casually I stay around 190-195 and on the freeway ziping in and out of traffic I'm at 205-208. Engine feels better without all the weight. Side Note: Depowered rack is giving me muscles haha and feels nice and tight in the corners. I love being able to feel the resistance in the wheels to let me know when to back off and slow down before understeer occurs.

Just got done troubleshooting my car.

Pretty sure that the bearings in the compressor are shot, and it's pulling a lot of load, causing my overheat.

My compressor sounded like shit too. When I turned on the ac it would sound like flywheel chatter. I bet thats what was causing me to overheat as well. I didnt feel like messing with it anymore and didnt want to spend money and time trying to figure it out anymore.

Not sure if that'd happen at speed, but maybe?

It's a bit more reasonable as a percentage of load at idle, I'm curious if it could cause an at speed overheat.

I'd imagine so seeing as more stress gets put on the motor. Before I removed my ac I was getting 200 + at idle with out even moving the car. Simply just starting the car and letting it run. Now I sit at about 180-188.

As well as putting a load on the motor, you had a nice hot heater in front of your radiator to warm the incoming air.

Here's an interesting data point.

The only time I used to overheat was when sitting in traffic with the AC on MAX and the idle speed really low because of the engine load. Car would never overheat with any forward movement, including track sessions.

I recently did a mod to my ECU firmware that bumps the idle speed by a good amount when the AC is on. I'm idling at about 1200RPM in that condition now. I've noticed that I'm no longer getting hot. The added water flow through the engine and radiator and alternator juice available to the fans makes a big difference.

My setup is OEM radiator/air guide/undertray/fans/thermostat and a coolant reroute.

Scotty,

I just read this thread because I'm facing a similar problem and remembered about a discussion on "Mini Cooper Hood Scoops" we had some time ago. Here's a link to one of those threads to see if it helps you solve your issues:

https://www.miataturbo.net/general-m...tractor-18189/

Well, look who popped in. Hey Rafa!

Hey shooter! wazzup?

Todo bien. Just getting older fast :rofl:

I put in an extractor from a gt500. Check out my "Crumpled Beer Can" build thread. Thanks for the heads up though

I know I'm late to the party but......

Scotty IMO, your problem is the radiator. If all the suggestions on ducting and bleeding the air and coolant re-routing didn't do the job, replacing a two year old radiator should have been your next step as opposed to removing your ac system. While the aftermarket fans may not have been better than factory, if the car didn't overheat while parked when you did that test, they were not the problem. Yes, turning on the ac will create more heat in the cooling system as it takes a little more power to run it and the condenser will soak the radiator with hotter incoming air but not enough to overcome the capacity of the cooling system unless the cooling system is suspect to begin with. Oh, and the noise the compressor made when you first turn it on and let it run at low engine speeds is normal for most of these older small displacement R134 Japanese cars. I think its a lack of oil flow in the refrigerant causing the compressor to rattle like that.

Nagase IMO, your problem is the fans. If your car overheats at idle and not at speed, you are not getting the heat off the radiator. Case in point, as soon as the car starts moving, it cools off. Nothing to do with failing bearings in the ac compressor or bubbles in the cooling system because as soon as you start moving the fans are useless.

I put in a new mishi(waranty) and still ran the same temps. The only way I have ever really got them to lower was ducting. Now I suspect I need better fans cause it gets a little hot( 215-220) in 90 deg stop in go traffic than I oncew on the highway it will drop to 190-200 range. Ducting was the best thing I ever did as well as buying a magic funnel.