bl0d

I ordered a new thermostat from RX7store the other day because i noticed that my car would normally warm up to 1/2 way on the temp guage and after awhile of driving would slowly creep up higher. Today after getting gas and driving around more than i usually do, i noticed it get to almost 2/3s before i got home. After popping the hood i heard the coolant boiling, but nothing was coming out of the overflow. I was poking around while waiting on it to cool down enough to check a few things on it, i noticed that the coolant level sensor wire was a little loose...and ended up pulling 1ft of wire up to discover the end was cut and taped up with electrical tape.

I've been under the impression that if it's disconnected or grounded, the ECU will light up the Low Coolant light, so how come it isn't?

I'm going to do some more poking around to find the other end of the wire when it cools off some more, but i'm highly disturbed by these little surprises...

bl0d

Some pictures for added effect. The first is of where my temp normally is when warmed up, then where it was today, the wire to the coolant level sensor as i found it at first, and where the wire is cut. I've been trying to find where the other end of the wire is, but no luck in the FSM or Haynes.

NZConvertible

Just grounding the sensor won't do anything. To disable the low-coolant warning you have to ground the harness side of the connector, which it sounds like someone has. Find it and reconnect it so the system works properly.

BTW, the ECU has nothing to do with it. The coolant warning is controlled by a unit in the instrument cluster.

bl0d

Where is the other end of the wire supposed to be at? I found one likely wire (thin, brown), and it is grounded (right by where the bottom of the airbox bolts to the front support that the radiator is attatched to), but it was dark out so i couldn't trace where it went

I'm guessing that it would need to be grounded much further back than that, but getting it connected is one of my main concerns right now.

SureShot

OK - you're after the gator - now about the swamp.

Overheating is bad news for a rotary.

Sureshot’s Overheating – check list
1) Replace the thermostat. Make sure it fits. The spring loaded disc under the stat valve must close the bypass port, or guess what? –You get symptoms like a blocked radiator.
2) Replace the radiator cap. Low pressure = steam bubbles = spit out coolant.
3) Look for leaks. (same symptoms as #2) Some can be very hard to find. You may have to pressure test it. A common failure spot is the 3/8” coolant line that runs from the top of the rear housing (under the intake runners) to the throttle body, to the BAC, to the water pump. Another one is the heater hose under the oil filter.
4) The fan clutch will slowly start slipping as it ages. The fan should pull really hard up to about 3k when the motor is hot. It should maintain about 3k as the motor revs higher. Sometimes you can get more life from it by bending outward the bi-metal strip on the front of the fan clutch. The cut-in for the series 4 fan clutch is gradual – it pulls some even when cold. The series 5 fan clutch is more on/off. If your fan only revs to 2K, the clutch is worn out.
5) The rotary engine gets almost half its cooling from the oil. The oil cooler is as important as the radiator. Make sure it’s not blocked.
6) Is the oil cooler thermostat working? The oil cooler should not be cool when the radiator is hot.
7) Are the stock top covers & front undertray in place?

NZConvertible

That's it. Remove it from the chassis and the buzzer should sound.

bl0d

Been a long weekend at work, but i finally got to take care of the thermostat. Now it will get up to 1/3 on the temp guage and sit there for awile, occasionally going to somewhere between 1/3 and 1/2 before going back down to 1/3. All in all, happy camper.

J-Rat

iTrader: (2)

Dude, is your oil pressure usually that low?

matts86fc3s

damn, that is pretty low. mine was always sat about 3/4 of the way up at idle and pegged out when i was driving.

Syncro

iTrader: (1)

THAT sounds too HIGH, doesn't it?

cool_as_crap

yeah, mine ususally wavers between 30-60

bl0d

My oil pressure at idle does seem a bit low, but when i've got actual load on the engine @ 2k rpm it's just under 60. I can verify the numbers tomorrow, but the last time i checked i was only low when idling, and even then it doesn't look dangerously low for idling on a fully warmed up engine.