Mikeee

I have an 81 GSL, and it seems to be running a little hot, but I dont know if its normal or not. I mean It doesnt ever hit the red line, but it goes 3 quarters of the way. Is it normal to go above half the gauge?

thanks for any feedback.

Wankelguy

Mazda temp gauges aren't calibrated real well.
If you're worried, get a thermometer and measure the water temp to establish a reference point.

Rx-7Doctor

iTrader: (13)

Normally they run 1/2 or below. How old is the t-stat and do you know what temp it is?

Mikeee

I have no clue honestly, i just bought the car 2 days ago.

Rx-7Doctor

iTrader: (13)

Ok. First thing to do is buy new t-stat and gasket, use oem temp. Flush the cooling system and install new coolant. Check the hoses for either being too soft or too hard, replace as needed. Change the oil and filter using quality filter such as napa gold or oem only. Use 20w50 oil. Austin is a hot area, i know i spent 3 years in Houston. Make sure the water pump belt is tight. Also check the operation of the fan clutch. After the engine is up to operating temp. Shut the motor off and spin the fan. It should have resistance in it and should not spin very freely. If it spins around with no resistance then it is bad. After changing oil/t-stat and
changing coolant. report back to see where she is running at.
Forgot to add check the seal on the radiator cap. If it looks deteriorated replace also.

Mikeee

Excellent! Printed and will do 1st thing tomorrow morning. thanks, Doc!

Mikeee

Oh, one last thing, some poeple say mix coolant and water at a certain ratio, is this true or should I do 100% antifreeze/coolant?

Rx-7Doctor

iTrader: (13)

50/50 mix is the norm. Happy wrench ing

Mikeee

woohoo! thanks again!

speedracer_not

100% antifreeze freezes at slightly above zero Centigrat not Kelvin.

I had mine freeze in New Jersey, but luckily the motor was unharmed.

Dan_s_young

iTrader: (1)

be sure to get it fixed fast, rotarys overheat and get wrecked... On my old engine the housings warped because the temp gauge was at 3/4 for about 2 minutes

tempusfugitive

i know on mine, it ran about 3/4 on the gauge when i bought it, last winter i replaced the rad, rad hoses, heater hoses, t-stat, and coolant. and with the current 86'F weather outside the gauge doesn't go above 1/3, for cooler weather it stays at 1/4. i'm curious to see how low it will go when i put in the e-fan and FC oil cooler next winter.

JKM

Don't forget to look into the archives on the threads about getting air bubbles out of your coolant system. Just as a reference, when I got my car, normal operating temperature was just at (maybe a hair below) halfway on my temp gauge. After flushing the coolant (twice, there was much gunk), replacing the old hoses, new thermostat, and getting the air out normal operating temperature is quite a bit shy of that halfway mark now, no matter what I'm doing to the car. Mine isn't an 81, so your temp gauge position is probably different, but that gives you a good idea of what a good flush can do.

H4Inf

Hmm just wondering is it possible for the temperature to be too low?

My temp gauge never rises more than 1/8th an inch above the bottom. I have an aftermarket 3 core radiator, and no aircon in the way of it.

Cheers

Mikeee

UPDATE: 1st off, thank you very much for all the advice, newbie here really appreceates it!

Replaced hoses, thermostat, gasket, radiator cap, flushed, oil change 20w50, new oil filter. Checked fan resistance (good). While at it I replaced the fuel filter as well.

Unfortunetaly, nothing helped. Still above half mark, about 3 quarters of the gauge. Im going to look into at JKM's idea to release any bubbles tomorrow. Any other ideas for me to do tomorrow?

cdrad51

replace radiator. That did it for me.

John64

You can put an aftermarket coolent gauge in. It will be very acurate. I put my sensor in at the block heater (cold climent) inlet at the bottom front drivers side.

Mikeee

I buddy of mine just asked me if it was possible that the thermometer sensor is bad, make sense?

glewsRx

iTrader: (1)

Mines doing the exact same thing. Replaced the tstat and that didn't help... It didn't hurt either. I think its the clutch fan on mine and yours too. Flushing and replacing the fan this week. I hate loving this car. If you give it an inch, it'll take mile.

ray green

iTrader: (14)

Could be, but basically it sounds like your stock temp guage works, you just don't know if it's accurate (what it's calibration is). I think John64 has the right idea, put an aftermarket temp guage in (or find some other more convenient way to measure the coolant temp at running speed), then you can use the aftermarket guage to "calibrate" your stock guage. Having the second temp guage in place doesn't sound like a bad idea anyway, John64 can you give us some details on how to install the guage and how much money and time it costs?

Ray

ray green

iTrader: (14)

From HFNf's post:

"Hmm just wondering is it possible for the temperature to be too low?

My temp gauge never rises more than 1/8th an inch above the bottom. I have an aftermarket 3 core radiator, and no aircon in the way of it.

Cheers"

If your thermostat is going bad or improperly installed, it can cause irregular and/or low temperature guage readings. I know, I let the thermostat slip a little when I was putting it back in, so coolant was getting past the seal. I was happy with the real low temp readings, but didn't like the idea that it took a long time to warm up and the guage wasn't showing a nice constant temperature, as it should if the cooling system is working properly.

The slow warm up cuts into your performance and gas mileage and probably isn't good for the engine either (in cooler climates it could be a damn nuisance). Reinstalling the thermostat fixed this for me, I imagine an old thermostat that's leaking or sticking open you would give the same symptoms.

Incidently, the 20 year old stock RX7 guages can give quite a range for "normal" operating temperature. My tan 84 GSL runs just above half, my white one about a quarter and the brown one in between. It probably doesn't mean much to compare your guage against others, just look out for abrupt changes or readings at one end of the scale or the other.

Info from the college of hard knocks, hope it helps.

Ray

John64

No problem. I picked up the Autometer water temp gauge from Sumitt for around $80, I think. The hardest part was finding the right location for the sensor. You cannot put it in the factory location, even with adaptors. Some people will tap the water housing, but I did not want to go that far. The temp sensor will fit in without any mods to the front housing drain plug on the drivers side. In colder climets, its used to put an engine block warmer in.


you will still have your factory gauge to use, so you can have to forms of temp.

hammmy

With all the coolant flush suggestions in this thread, I didn't see anything about using deionized (or is it distilled?) water. Isn't that what is supposed to be used in mixed-metal blocks?

Anex 570

Yes sir. I actually found a good result using the sierra or yellow antifreeze. I did not pay for it though.. heh . For summer time I'm running distilled water, water wetter, and a little glycol. More glycol or drain it for the winter.

capt murph

Hold that wrench Mikeee!!
I think a better approach on your new car might be to determine the actual temperature, and see if a problem/concern really exists. As others said, there may be error in the gauge. It would be better to know this fact before you break a bolt or something changing a part that doesn't need changing.

There are many electronic thermometers that you can purchase, or find a friend that might have one. Refrigeration technicians always have some means to measure temps , if you know any of those guys.

Good luck with your new ride.