Overheating? High idle, wierd problems....Please Help!!!

I just bought this 89 SC 5 speed a few days ago (private sale), and on the way home, I noticed the the temp guage was rising and not going down at all. On this 25 mile hike home , on the highway, the temp slowly pegged the factory temp guage. I new this was a problem, I checked the water level, it was fine, the fan was running, I even had the heater on to add additional cooling, but the SC remained pegged. Now, I drove this home and for 20 miles it did this, and did not explode like I thought it would do. Since I have hot air coming from my heater, it seemed that the thermostat was working, along with the water pump. However, when I did arive home, the car was still running fine (idle was too high, but I think that was the IAC needing replacement, yet another story), and I shut her down. I asked my mother for a towel to remove the radiator cap and to my suprise, there was absolutely zero pressure in the system (this was only 2 minutes after pulling in with the temp guage pegged!!). I was very surprised at this as I thought it would be bellowing out steam and look not too much like old faithful!! So I started the SC without the rad cap on, saw no movement in the coolant, nor was the cooling fan on. Any thoughts on what this could be? There appears to be no white smoke from the exhaust so as far as I know, the Head Gaskets are ok (it runs well). I do have an extra radiator from my 1990 SC that I used to have, I am thinking that it may be the radiator, but if anyone else has a clue, your advice is welcome.

Thanks

Phil Stocker

just a shot in the dark here but maybe the Rad or somewhere inthe cooling system there is a blockage preventing movment of the coolant thus not pressurizing the rad, other then that I have no idea.

You’re probably low on coolant. In these cars the upper rad hose is higher than the rest of the system and is hard to get all the air purged from the system. Look to the right of the thermostat housing (Where the upper rad hose attaches to), there is a bolt with a plastic cap on it. Remove the bolt (use a backup wrench on the tube or you might twist the tube). Remove the rad cap and fill until coolant comes out from the tube (Be sure to rinse the front of the engine down because the coolant can cause the crank position sensor to fail, I don't know why since it is a magnetic hall effect switch, but it does).

Make sure the rad cap is good (if you have the slightest doubt replace it). Make sure the coolant overflow holds coolant and doesn't leak, or it will do it again. Run the engine, drive around the block a few times and shut the engine off. Do this a few times. The object is to allow the cooling system to pressurize and then cool. The expansion and contraction will expel the air and suck in coolant to replace the area occupied by the air. After things are working properly then only coolant will pass back and forth between the overflow and rad.

Jeff

This is probably the #1 cause of headgasket failure (over heating)

Cooooooooling

Another thing to check is - make sure your fan is working. Start the car and turn on your AC. The fan should be on as soon as the A/C kicks in. If you don't have any coolant movement after a few minutes of running, change the Thermostat, and hope it's not the Water pump.

JT