5.0 and 5.7 Discussion, 5.0 307 Oldsmobile 1987 Fleetwood Brougham Oveheat in Cadillac Engine Technical Discussion; Hey, I drive a 1987 Caddy Fleetwood Brougham Hearse (yeah, THAT kind of Hearse) and the engine has been having ...
Hey, I drive a 1987 Caddy Fleetwood Brougham Hearse (yeah, THAT kind of Hearse) and the engine has been having a strange issue lately. If I drive at about 65 or so for a while the COOLANT TEMP light suddenly blips on. If I slow down, it stops. This is a new problem of the many I have had. The water pump and thermostat are less than a year old, so I would not imagine it is that. The belts are new too, though I will try having them tightened to see if that helps, because sometimes I hear them squeak. I hear that it may be the Fan Clutch. From my understanding, the best way to test the clutch is to let the engine warm up a bit and then turn it off and try spinning the fan. It should have "moderate resistance" and then you should heat the engine up with a short drive and test it again. It should have an increase in resistance.
Does anyone have any idea what the problem may be? Anything I missed?
Hey, I said "if I slow down it stops" and what I mean by that isn't that the car stops, I mean that if I slow down a bit when the COOLANT TEMP light goes on that the light will go off. Nearly instantly, actually.
When the engine is cold, open the radiator cap and check the coolant level. If it's low and your overflow tank is full; you have a bad radiator cap. Try that for a start. I had over heating problems with an '87 that I had. It turned out to be the radiator core.
The fan clutch disengages at freeway speeds so its not that. You have a classic symptom of a plugged up radiator. Faster you drive, the faster the coolant must circulate. If it cannt circulate fast enough then the engine holds hot coolant so eventually the engine temp is above normal. Pull the radiator and have it flow tested to confirm. Dont be surprised if the radiator shop says the core is thin and cannt be rodded to unplug it. Be prepared to replace the radiator. THIS CAR NEVER WENT PAST 50 MPH PRIOR TO YOU OWNING IT SO NO SURPRISE. AND THE RADIATOR IS 22 YEARS OLD AFTER ALL!