fan switch+head temp sensor...test while installed?

[OK-944]

Took my 85.5 out for a 15 minute run yesterday evening...with outside air temp. hovering around 80f.

Engine temp indicator came up to just over the first mark and stayed there...and the fans did not come on.

Pulled back into my garage and popped the hood - burped a tiny bit more air from the top water neck bleeder, as I've been doing all week. Looks like I've gotten pretty much all the air out of the system (heater controls have been full-on).

Both top and bottom coolant hoses get hot (indicating circulation?)...as does the cam cover (seems almost too hot as I've mentioned before).

While resealing the engine, I thoroughly cleaned the temp sensors and connections, and given the rate of indicated temp rise over a given time interval...I suspect that the readout is accurate.

But I'm still paranoid that the car is somehow overheating.

Are there ways to test both the fan thermo switch and head temp sensor while these are still installed in the car - without draining coolant and removing them? Perhaps I should have simply asked this without providing other details - but sometimes details are useful also. Thanks!

[krystar]

maybe try one of those temperature readout coolant tank caps.

[mikepellegrini]

For sensor testing, there's this at Clark's: Sensors and Gauges - Information, Troubleshooting, and Testing

For the thermofan switch, the only way I know to conclusively test it is to take it out and boil it and see what temperature the switch closes at.

However, with the car running, you ought to be able to get a rough idea with an infrared thermometer.