momar

My cars temp gauge would normally be around 1/4 of the way up, which is normal from what I hear. I did the ATF trick and now the temp gauge goes up to 3/4 of the way up. What could be causing the change in temp and how can I get it to run cooler. I just get nervous seeing the temp that high.

Thanks in advance
'86 N/A

Scott 89t2

I can't think of anything that would effect it. did you change the plugs after?? if not maybe it's detonating a bit on you with the fouled plugs. that would cause the heat. other then that I can't think of anything that would be related. did you do anything else at the same time??

momar

I changed the plugs and wires, but I don't see how that would affect the temp. I am going to check the radiator today and see if there is crap on it that is blocking the air flow.

momar

nothing was blocking the radiator, could it just be a bad temp gauge? I drove it for a half hour and it just stayed at a little above the 3/4 level, what may be the problem?

Scott 89t2

does your rad or rad hose seem hoter then before?? if not it could be the gauge. but if the gauge is right you don't want to be driving at 3/4!!

the sender for the gauge is down below the oil filter, below the oil pressure sender. see if you can find it and make sure it's connected good and clean. maybe you hit it while trying to put the atf in...

but if they are hotter, or seem to hot then it's needs to get looked at before you drive much more.

how old is the coolant and thermostat?

momar

I'm not sure how old the coolant and thermostat are. I am going to flush it soon, so hopefully that will help, and I'll check that sensor tomorrow.

fc3s.org

Also check the drag on your slutch fan. If it is really easy to turn, then you probably need a new clutch for the fan.

momar

I checked the fan and it had resistance when it was warmed up. I also noticed that when the car is warmed up the radiator is not even close to being warm. Could the radiator be clogged or is it time for a new one.

Scott 89t2

it could be the rad, but I'd change the thermostat first. if it was stuck that would cause the same thing. it's cheaper and should be done anyways so try that first.

fc3s.org

That sounds like the thermostat is bad. Go to the dealer and get a new one. it comes with the gasket. Don't use the crappy autoparts store ones. Go OEM with that part. It would be a good idea to flusht he system too so get some coolant and distilled water.

momar

If the thermostat was bad would the upper radiator hose still get hot? Either way I am still gonna get a new one.

fc3s.org

If the thermostat was just opening a little, then yes the hose would still get hot from the hot water getting into the hose, but if I were you, I would do a full cooling system cleaning or you might loose your RX-7 motor.

Parts you need:

Coolant - 1 jug (gal)
Distilled water - 2 gallons
Thermostat - OEM Mazda (1)
Radiator cap - OEM Mazda (1)
New radiator hoses - Upper and Lower (1 ea)
Prestone radiator flush - one bottle (1qt I think)

Process:

Drain out the old coolant from your radiator and from the block. The drain for the block is in your drivers side motor mount. It looks like a long bolt head with no visible threads. Unscrew that and let it drain. Remove the thermostat housing nexk and take a hose and flush down into the block. Let it do that for approx 5-10 minutes. Then do the same with the radiator.

The plug back in the drain plug on the block, and reconnect the radiator hoses. Refill the system with plain hose water and that radiator flush. Then top off the system and drive around for an hour or so. Then come back home and let it cool completely.

Drain the system again. Repeat all of the above processes. Then replace the radiator hoses. Replace the thermostat and radiator car. Fill the system with a 50/50 ratio of distilled water and coolant. Start the car and check for leaks. They will steam when the car warms up if there are any. Then take it for a drive and see how it works.

momar

thanks everyone for the help. The parts should be here in a few days and hopefully that will bring the tamp back to normal.

HAILERS

MOMAR.. ....why not just remove the thermostat while you are waiting? Takes about fifteen minutes, you'll be able to drive it, and you'll be able to confirm that the problem is nothing more than the thermostat.. Car can be driven just fine without one. It should run rather cold, like the needle in the lower 1/8th of the gauge, and will be slow to warm up. Big deal. OOps, just noticed you live in MN. Might have some trouble defrosting the windshield.