Bros, why is my daily overheating?
 

The car is running hot in traffic, hotter of course when the AC is on...it was 109*f outside yesterday. My CEL flashes at 220*, the radiator boils water occasionally, but the temp-strip on the top of the rad says it's never been over 220*f.

• The water pump is 2-years old
• I have a CX racing radiator
• Murray 1.3BAR radiator cap
• Fans are sealed with tape to the radiator (temporary)
• 180* old thermostat checks out okay, a new one is in there anyway

If I can make it to September with this ----, I will live.

reroute?

Negative. A stock Miata should be able to handle this heat. It did in previous years.

I suspect that I could be losing water possibly, the calibration could be off on the sensor, or I sabotage.

Are the fans coming on?

If they aren't coming on: Disconnect the fan and wire it directly to a battery. If it spins it's the relay, if it doesn't it's the fan itself. Twice I've had a relay to the fan die, and replaced it at a junkyard for $1. Tons of cars use the same relay.

If the fans and thermostat are working it's most likely a waterpump or headgasket.

Edit: Is this a 1.6? Could be the "Cursed Water Plug"

Fans?

Obstruction?

Our '92 overheated...a lot. The first answer was a big PWR radiator. I later did the reroute and ran a stock automatic radiator and kept the same temps.

Sounds like you've got something else compounding the problem.

Fans come on and feel strong. Condenser and radiator are fairly clean.

When stock cars overheat, they are broken.

Check in this order:
-Low coolant level
-Lack of OEM ducting/shrouding
-Leaks (invisible ones)
-Leaks (big -----off ones)
-Radiator obstruction

When you are sitting at your apartment can you get it to overheat just sitting there? IE does the fan turn on and then not cool it down enough to turn back off?

Radiator fluids fresh? What kind of mix are you running?

Air bubble? Give it a bleed maybe...

With the AC on, yes.

I used magical funnel, was fairly certain of no air.

Just a couple cups of anti-freeze, the rest is distilled water.

Coolant is full
OEM stuff is there.
There could be a phantom leak, but pressure tester says no until the rad cap leaks.
I can see through both the rad and condensor.

All this makes me think the water pump is either not effectively moving water, or there is a leak.

Radiator says (according to "temp-strip") less than 120, but CEL flashes at 120, means the block is hotter than the radiator. I think that points to circulation:

Blockage - foreign matter or air pocket
Pump not working as it should

Check the flow.

Also, radiator will transfer more heat to the atmosphere if you run a 195° thermostat. Assuming there is water flow of course.

220*f

I dumped some dye in there today, I guess I'll go look for the leak when I get home.

Stat sticking closed due to used condom?