cloudz

iTrader: (1)

Hey guys I just bought a 1991 rx7 with 67k miles. The motor seems to be running strong, but I have a few concerns.

1. The car overheats. I had to drive it about 10 miles to get home, on the way back, the water temp went all the way up and went back down to the middle but jumped back up a few times. Did i break anything if i drove it on the Hot for a few miles? I actually drove about 5 miles and took a 40 min break, then another 5.

I got most of the air out of the radiator and filled it up with coolant (there was a lot of air inside it). It seemed to run fine and stayed in the middle of the water temp gauge for the next 50 miles i drove. Earlier today (after a night cooling down completely), it jumped back up to the top of the temp gauge for about a minute and shot back down to the middle.

I do not know why it jumps back and forth. Maybe a faulty sensor? Regardless, im 90% sure the motor is not blown. I've driven it up to 90mph and its strong, no weird sounds or anything. No white smoke out of the exhaust. I'm also sure the coolant is not leaking into the engine. There's too much coolant in the reservoir and radiator for it to be leaking into the engine.

Does anyone know what I need to do to fix the overheating issue? Perhaps there is more air in my radiator? I was thinking of just flushing the radiator very well twice to make sure i get it all, and change the water pump+thermostat. What else could I do? I would really prefer not buying a new radiator because if I did it would probably have to be a Koyo which costs $300.

2. My stock stereo screen lights up, but there is no display. Only the orange backlight works, there are no letters. The stereo works though, so do speakers. Do I just accept this, or is it fixable?

3. Power mirrors dont work

4. Power locks are slow, sometimes when I lock using the driver door, the passenger one doesn't move so I need to do it 2-3 times.

5. Power windows are slow

6. My driver mirror shakes a lot when I drive on the highway, it's difficult to see cars since its always vibrating. Perhaps a screw?

Thanks if you guys took time to read this. Sorry if there are too many questions, I just wanted to get it all out there. I've tried looking for solutions with the "search function" but not much comes up.

Please help with anything you know, if not I hope the answers in this thread could solve any issues you may be having yourself.

clokker

iTrader: (2)

1. You have air in the system. Your best move would be to drain out the old and start with fresh coolant. Make sure your heater temp is set to HOT so you don't trap air in the core.

2. Dunno.

3. Check the CIGAR fuse (in the footwell)

4. Clean all electrical contacts and lube whatever looks reasonable.

5. Common problem, two stage fix.
-Clean window track and relube. Make sure window isn't binding. Clean contacts in switch.

-The real problem is that Mazda runs all the power for the window motors through the switch.
This degrades the contacts and chokes current to the motor. Window switches from MPV vans will work with some wire reconfig and are reputed to be sturdier.
A more permanent solution is to relay the system.

6. Is it the mirror or the housing that moves? You can access the mount screws for the mirror by removing the inner triangle (which you will break)...there are three large head phillips that secure the whole assembly. If the mirror itself is rattling inside the housing, I have no idea.
Get another mirror, probably.

cloudz

iTrader: (1)

Was there much harm done to my motor from driving it back home with the overheating engine? It fluctuated between the middle of the temp gauge to the top a lot and I think I may have broken something.

Also, the "add coolant" light goes on for under a minute sometimes then goes off. I have never heard a buzzing sound in the car which is supposed to indicate low coolant or an overheating engine.

ncds_fc

I was having similar cooling system problems on mine. Its a 90 S5 N/A. My temp gauge always stayed at normal (middle), but from time to time.... my add coolant light comes on. I replaced my radiator cap, then later my radiator hose, found rust in it. I flushed the radiator twice.... bit after warming up, everything was fine till my thermostat housing cracked at the seam. OEM was plastic, so I ordered am aluminum one from Mazdatrix. Waiting on the part now. Reservoir tank always ended up full after a drive before all that.

Saw Mazdatrix notes on radiator and cooling system.

About to clean my fuel system with those fuel system cleaner things, since I smoke like crazy after I fill a full tank. My motor might be gone, but I'm about to try a compression test to be sure.oh, and I notice there is air in my cooling system, cruz I can hear it, and radiator cap didn't seat well. That's just what I'm going thru with mine.

clokker

iTrader: (2)

Well, maybe you did break something.

The S5 temp gauge is more a dummy light than a gauge and not to be trusted.

cloudz

iTrader: (1)

anyone else know stuff about the other issues?

VANHALEN

iTrader: (3)

You're asking people to diagnose your car with your description.
That's a hit and miss.

Your overheating problem seems like a gauge issue.
Key to that was telling us your gauge went down down to rest and started fluctuating. That points to a defective gauge. If it WAS working properly and you did overheat, it never would go all the way down and back up again and fluctuates.
If you want to check, open the rad. cap (when cold) and let the engine run to temp. .
If coolant starts to push out from the filler, that's a bad sign.

If your descr. is correct, sounds like a bad gauge. Could be the sender or gauge.
Try replacing the sender since it's cheap and go from there. As Clokker said, S5 gauges are off..normal..high. Unlike S4 gauges.

Thse cars are at least 20 years old. Expect propblems.

clokker

iTrader: (2)

I disagree.

Air trapped in the system will do the same thing, so will a sticky thermostat...both more likely than a bad gauge/sending unit.

cloudz

iTrader: (1)

So I am planning to do a full coolant flush (as best I can), new water pump, new thermostat this weekend. Do I need to replace the radiator? Also I heard a broken fan clutch could cause the engine to overheat?

If I have a bad temp. gauge, which gauge do you guys recommend?

Thanks