stevepaa

So my car oil temp went to 10 o'clock for the first time ever, 217k miles, and so I turned on the inside fan high just like I used to do with the MGA. It brought the temperature down.

In troubleshooting I think I have isolated it to the temperature sender from the oil cooler. I get about 4.6 K ohms when warm, goes to 1.6 k ohms when near the point to operate the fans, and then goes to 6 k ohms as it got hotter.

weird. I thought it should fail safe. go to 0 ohms closed circuit!

Laker

Also check the ceramic resistor on top of the fan housing cowl.

Black930

+1 mine was breaking apart. Easy fix.

stevepaa

That resistor is okay, I replaced it at 160 k. And it checks out as I get both low and high speed fans when I jump the relay contacts

stevepaa

Got the new sender from dealer

wrong thread size 12mm

not 14mm like original

quality control is completely lacking here.

stevepaa

2nd unit from dealer was correct size, car running fine and cooler fan works.

strange that the device failed into a no-safe position.

Dealer was puzzled how the part with wrong thread had same part number.