560 sl over heating

[kennedy]

I have been using my 88 560 sl in a few parades and the temp gauge shows its getting hot, how can I check the fan clutch to see if it is working correctly? The temp is fine during normal driving, but at idle during a parade it heats up.

[alabbasi]

This may seem mental but it's it's how you check it. Run the engine until it gets to operating temp and then use a thick towel (balled up) to attempt to stop the fan. If you can stop it, then the clutch is bad.

[kennedy]

when should the Aux fan come on?

[alabbasi]

212 degrees or when the a/c is on.

[kennedy]

can not get the aux fan to come on, fuse is ok, what else to check?

[kennedy]

is there a relay in the system?

[alabbasi]

Try pulling the plug on the 212 switch and grouding it to see if it engages the fan. If it does not, then try putting power directly to the fan and see if it runs.

[kennedy]

I hooked my battery charger directly to the aux fan and it came on, I jumped the 2 prong connector to the engine temp sensor on the thermostat housing and the fan came on, I jumped the temp sensor on the a/c dryer and the fan came on. could I have a bad engine temp sensor?

[alabbasi]

Either that or a bad thermostat. If you're not getting water where the temp sensor is then the temp sensor is not going to function correctly.

For now, use a GM style fuse to jump the temp sensor at the drier so that the fan runs all the time during the summer months. Does your A/C work?

[kennedy]

Since I am only having the overheating problem when idling in a parade, and not everyday driving, I will use your GM fuse idea only when needed in a parade. thanks.

[alabbasi]

OK Good deal, test run it in traffic conditions before the parade. If it's a closed thermostat, the aux fan will not help much and you don't want to find this out while you're stuck in the middle of a parade