1989 cooling fan

Congrats on the "new" C4!

'89 has a primary fan behind the radiator. Some "sunbelt" cars also have a smaller aux fan in front of the radiator.

Turn on the A/C -- this sends a signal to the ECM (computer) which controls the fan and the fan will run. If that isn't happening, troubleshoot the fan power and control circuits.

I don't recall when the system vents due to over-pressure but 299 sounds quite high--maybe an error. What's the oil temp doing when the coolant is this high? (Once the engine is warmed up, lube and coolant temps will usually be within 20 deg of one another.)

Best cooling is over 40 mph. If you drive a steady 45-50 and the OAT is under 85, you ought not see temps much above 215 deg (A/C off, and fan either on or off). If you are getting consistent high temperatures then look for twigs, leaves, dirt and road trash lodged between the A/C condenser and the radiator. (Ugly job but it's needed from time to time.)

Hang loose, move slowly, drink lots of water, sweat nothing and remember to wave!

-- PJ '89 Hookercar '02 e-blu coupe

Cooling fan 'should' kick on somewhere around 235 degrees. Sounds like the temp sensor ( switch ) to turn the fan on may be bad. I replaced mine with a

also for the guy who can't get his cooling fan to shut down ..turn off your A/C.....!!!!!!!!!! Simple as that.

The circuit is simple enough, power to the fan is fed directly from the battery thru a relay. Relay can be 'burned' ( contacts welded ) or the sense lines to the relay ( temp switch, ecm ) can be supplying a constant ground ( or wiring to/from can be shorted to ground ). If your mechanic can't trouble shoot a 'simple circuit' like this ..... change mechanics. You should be able to fix this in an hour with a cheap volt / ohm meter.