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Patient: 1992 Mx-3 GS 5spd 146,xxx kms
Problem: When cold, idles at 2000rpm at start(this is fine) but doesn't drop. After 4 minutes of idling, rpms jump to 2500.
Heat is on, air is lcy Cold.
After a couple minutes, rpms drop to 2000, Oil Temp indicator is still pegged at C.
Oil temp rises above the line above the bottom, stays there, then jumps up to normal temp(1mm above center).
THEN!
Rpms drop to 1500, then 1000 but at 1000 jump to 1500.... engine revs itself a few times, then drops to 1000.
Heat still on full, air still ice cold.<p>When I drive it, the oil temp gauge jumps to high, heat coming out gets hot(finally!) and I watch the needle drop back to normal. Then the heat gets cold, and the cycle repeats.<p>Coolant is topped off, had a radiator flush in sept. oil needs changing in 500 miles, but is kept full.<p>I'm thinking thermostat. Anybody got some opinions?

i would replace the thermostat for starters bc its a cheap gamble and that will make ur temp gguage not work correctly and affect the heat coming from the vents.

When mines cold it idles at 2000rpm also. But when it warms up it drops down to 600-700 and the car runs fine. If these engines aren't supposed to rev that high cold, you may be looking at 2 different problems. But I would agree that your thermostat is probably sticking.

There is air trapped in the cooling system, my POS does it all the damn time, After you flushed it in Sept. did you keep letting the air out? how many times did you have to top it off in the filler cap?<p>I've have to do this tons of times, Jeff Abrams always has this problem too.

ya, Thermostat. If you guys want to warm up the motor, drive it...slowly at first....don't let it sit for so long ideling. It's bad for the motor.

mine done the same thing and i got to looking it had a crack in the radiator

you think maybe your thermostat is sticking closed? Does it fix it self eventually while driving?<p>Today I think I am doing my thermostat, upper rad hose and pressurized rad cap...
I'll let you know if it resolves anything...<p>[ April 11, 2003: Message edited by: killerpickle ]</p>

FYI Xero, that is a WATER temp gauge, not an oil temp gauge. Yes, it appears the thermostat could be your problem. A malfunctioning thermostat would also cause your BAC to adjust idle air.

okay, I re assessed my car problem. It turns out there was a small hole in the upper rad hose. Just after the sensor...this was causing some big problems...and making quite the mess. anyway 17.50 later, and about 3 minutes and I had it installed and the problem seems to be gone.

Just so y'all know...
All of the problems(according to my mechanic) came from having a leaky cap/seal. Not the one on the radiator, but on the engine. Apparently, even though I czeched the radiator, and the resivior(both full) I was down about 3qts of coolant. I feel like a total idiot, but hey... I'm learning. My mechanic couldn't find a replacement cap and seal, and says I have to order from mazda. You guys have any ideas on where else I could find this?
-T'anks for all the help.

a cap and seal for the engine? The radiator cap is the only thing I can think of, which you could jack off any junkyard mazda.

The filler cap is different to the radiator cap - it doesn't have a relief valve. <p>Is it worth getting a seal from a wrecker? Maybe it'll be worse than the one you're replacing!

<blockquote><font size="1" face="Verdana, Arial">quote:</font><hr>Originally posted by IanL:
The filler cap is different to the radiator cap - it doesn't have a relief valve. <p>Is it worth getting a seal from a wrecker? Maybe it'll be worse than the one you're replacing!<hr></blockquote><p>must be nice to have a 97 mx-3!