Help dx my cooling problem before I make the jump for a new rad....
 

Car is '95, shanghai kit, brain's mspnp... I'm so close to hitting the road and tuning! The problem now is I have a cooling problem where my megatune would read the CLT at 100~ or so, and it will slowly rise a few degrees indefinitely until I shut the car down. After 5 minutes of driving, it would go up to 200+! The fan isn't turning on, but it works when jumping it in the dx box (probably the relay?). I tried leaving both fans on, turned up the heater and that seemed to help keep the temp at 190~ for a bit.

1. Radiator cap has no leak
2. Waterpump just replaced with no leaks
3. Thermostat just replaced today, same thing.
4. Both bottom and lower hoses are hot
5. Tried flushing with water hose and new coolant, same thing.

Questions:
1. Read a lot at m.net, and I'm thinking it's probably the radiator? It's a stock radiator, but it has been replaced in the last 20k-30k or so. I'm going to make the jump soon if I have no leads on what to check next. Such a headache :facepalm:.

2. Megasquirt related, but how do you record a log (that .xls file)? I start the car, go to file-> datalogging -> log. Drive? Or is it "log-> drive ->log"?

Your fan isn't turning on when its supposed to and you think its the radiator? LOL

Do you know what thermostat you have in the car? It might not be opening until past 200.

What's the difference if I know that the fans are still working? From what I've gathered, it turns on at idle and when temp reading is over 206 (mine is not).

dustinb, I got a new 180 degree thermostat from flyingmiata.

Seems pretty normal to me. Prior to doing the reroute, my engine tended to run in the 195-205° indicated range, with a 180° thermostat. Of course, there can easily be 10° or more variance in the readings from one engine/sensor/car/MS to another.

The big question is: So long as you are moving at 30+ MPH, does the temp climb significantly higher than this? If not, then your engine/thermostat/radiator/cap are fine.


I never did quite figure out the fan control on MS1. My fans are just wired to a little toggle switch under the radio.


Depending upon which section you were in, I wouldn't be surprised if reading at m.net led you to believe that it was because your shift knob is the wrong color or your exhaust isn't loud enough.

Or that you need another PCPro.



1: Start car, turn on computer, load megatune, etc.
2: File -> Datalogging -> Record (or Alt-L)
3: Specify filename, press "Save"

At this point, you are logging to the file specified in step 3. At the bottom-right, the "LOGGING" indicator turns from grey to black.

4: When finished, go to File -> Datalogging -> Off. The "LOGGING" indicator changes from black back to grey, to indicate that you have stopped logging and closed the file.

Ahhh Joe, you're seriously one of my favorite posters here.

I've never tested it above 30 mph because I've been around my neighborhood all the time, but I haven't seen it hit over 210. It's just the gauge in megatune has the median well below 200 and the upper limit at 250.


Thanks once again! I'll get some driving soon later, too much traffic to drive around with no bumper or turn signals.

Well, you know what I mean- fast enough that some air is moving through the radiator. Any Miata with no cooling fans will overheat if it's just sitting still or tooling along at 5-10 MPH. But so long as you're moving at a decent clip, you can drive with no fans.


So? The calibration of the gauge in MT is pretty arbitrary, and you can change it by editing the cltGauge line under [GaugeConfigurations] in msns-extra.ini

I drove for a good 20 minutes last night and you're right, it went up to 206, but came steadily to 197 and stayed there the whole time. Now for more reading! Thanks guys.

Are you in the health care field popopop?

That sounds completely normal. There's always a little overshoot initially, and then it should settle down into the high 190s or low 200s.

Your cooling system is fine.