overheating 500SEC

[cellardoor]

I have two of these, '83 and '85 both with the same problem. On the motorway all is good, but stuck in traffic in London the temp creeps up until I have to turn the engine off. The aux fan does not engage. I have the manual I bought on disc, which naturally does not work. I see two temp sensors mounted high on the front of the engine by the water inlet. One seems to have a changing resistance, the other has an infinite resistance (open circuit), ov which i am suspicious. But I do not know if I am on t right path or not. Without the manual it is a trial and error deal. Anyone know what might be causing the fault? i even tried changing the open circuit sensor for one off another car that does ork and still no action????

 

[television]

I have two of these, '83 and '85 both with the same problem. On the motorway all is good, but stuck in traffic in London the temp creeps up until I have to turn the engine off. The aux fan does not engage. I have the manual I bought on disc, which naturally does not work. I see two temp sensors mounted high on the front of the engine by the water inlet. One seems to have a changing resistance, the other has an infinite resistance (open circuit), ov which i am suspicious. But I do not know if I am on t right path or not. Without the manual it is a trial and error deal. Anyone know what might be causing the fault? i even tried changing the open circuit sensor for one off another car that does ork and still no action????

Just short the sensors on the top to earth (chassis ) if the fan starts its the sensor, if not its the fan or fan relay and we can deal with that later

 

[star]

Just short the sensors on the top to earth (chassis ) if the fan starts its the sensor, if not its the fan or fan relay and we can deal with that later

The fans shud come in at around the 100 deg mark but mainly function to keep the a/c pressure down. have you checked that the rad is not partly blocked so not activating the viscous coupling??

I hate typing.

 

[cellardoor]

overheating update

Well I am finally geting around to sorting out that overheating problem.
So far.....
new radiator (well near new)
coolant system flush
thermostat replacement.
viscous fan locked of by bolting it to pulley on waterpump.
aux fan works well when aircon ativated and internal fan turned on

same issue remains.

runs at 100 on motorway

slowly creeps up to about 115 in slow traffic.

not losing water

has oil in sump.


next plan of attack...
find a mate with compression tester
and tester to see if hydrocarbons in water.

if no results...........swear a bit, then rethink

what is pulling at my coat tails is the fact that i have had 2 cars doing he same thing. had the other tested to see if head gasket was going, but proved not to ba the case. The only car i had that did not have this problem was rusted out and has gone for scrap (sad).
so what is the go with these V8s, is thois an endemic fault?

 

[Parrot of Doom]

Is the fan moving air in the correct direction?

 

[television]

Is there anyway that the engine is set with the ignition retarded, as this will cause it to run hot, just a thought