rasr1968

can anyone help me with this problem.
I have a 1986 gxl, there seems to be a cooling problem and can't seem to find a solution. here is what happens. When driving the car at highway speeds the temp is fine, but after driving it for a bit in city traffic the temp gauge starts creeping up the gauge. If you stop and shut her down it spits some coolant out the resevior. If you start her back up after cooling down it will be fine until you start driving in the city again. Also the darn add coolant light starts coming on. I have changed the thermostat, and gotten a new radiator cap (japanese) .9 bars. I know that this has probably been covered numerous times in the forums but when I do a search I can't seem to find anyhting. Could it need to be flushed out? I have also checked the fill neck when the car is running for the telltale bubbles but nothing. After driving it for a while it always seems to need some coolant. Also there is no white smoke out the exhaust. But there seems to be some steam coming from under the hood but can't seem to find the source unless it's coming from the overflow. any help would be appreciated.

BlackRx7

pressure test the cooling system and you should find the problem, doesn't sound like the engine O-rings, check the coolent line that goes to and front the BAC vavle....

yearrgh

Check the fan clutch. When the car is warm, turn it off and spin the fan by hand. There shoud be some resistance, if it freewheeles thats the problem. Also check the fillerneck, mine got chewed up somehow on the inside and wasn't sealing properly.

IWNTA20B

Well, to check if you did blow a seal, ope the radiator cap and crank the engine. If colant shoots out like a geiser, you have a cracked a coolant seal.
If you did fill or flushed the system, you need to bleed the air using the plastic screw on the side of the radiator. As for the steam , you could have a leak somewhere. Try taking it to a shop and have it pressure tested.

Icemark

It's the clutch fan, and make sure you used a Mazda OEM thermostat, not some silly stant from the local auto parts shop.

SureShot

The fan clutch uses a silicon oil viscous fluid in two chambers inside.
The Bi-metal strip on the front bends outward as it warms and opens the valve from the reservoir side to the clutch side.
Centripetal force provides the pumping action to move the fluid.
After 100,000 miles the bearing seals wear, and the bearing lube weakens the clutch fluid's grip.
The s4 clutch increases it’s bite gradually with temperature rise.
The s5 clutch is more on-off. (It just coasts until is gets warm)
Once they are warm, the fan speed goes up directly with engine speed to about 4000 RPM.
As the engine revs higher the fan stays at ~4K.
If your warmed up fan only revs up to ~2500 RPM, it's bad.

yearrgh

From my misfortunes I've learned that a BCS has to have gotten fairly bad before you get the geyser.