I have a sensor that is broken off behind the water neck that had a green plug on it. The only 2 sensors I could find are NF02-18-840 and N370-18-840. Does anyone know which sensor it would be?





Also, if that sensor was broken....what symtoms would I experience with my FD?

Thats the thermoswitch I believe. It is what tells the fans to turn on when the water reaches a certain temp( I am not sure what the stock setting is) You can overheat and ruin your motor without it. I would not drive until it is fixed.

I'm not sure if you are aware of this but if you want your fans to turn on earlier you can switch on the parking lights and this will trigger the fans if your water temp. is hot enough. It definitely comes in handy during the summer time.

I think that the green one is the engine coolant temp sensor. It sends the engine temp to the ECU. If it fails it can cause messed up air/fuel ratios and bucking when accelerating. If I remember correctly, it should throw code 09 if it is shorted or unplugged.



-Charlie

You can also turn the A/C on a run the cabin fan to kick the engine fans on.

I think Charlie's right. The green one, or the top most sensor is the coolant temp. The lower one, IIRC with a black plug, is the thermoswitch. Both are fairly important.

And since your already in there Michael, (and aren't already aware of it), the easiest way of lowering temps is to instal the FC thermoswitch. It will turn the fans on about 10 or 15 degrees earlier (IIRC @ 210 F. vs. 221 F. ) And it's simply a plug and play mod.... 89-91 FC thermoswitch Part #PN 41-18-840

green one is the nf02-18-840, its the coolant sensor for the ecu. if its broken, ecu will turn on the check engine light and assume the engine is at 80c

okay the factory water temp sensor on the fd is a peice of crap so try installing a 1st gen water temp sensor in its place and get a new connector they cost like $12 brand new and the last forever and yes the voltage is exactly the same. rotary performance did it to my car and it works great but if you don't have an after market temp guage get one cause the stock guage is only going to show 3 areas cold, warm and already overheated your motor so go ahead and rebuild it. to install the new guage you will ned to drill it out and rethread. it here is a pic on my car

sorry I didn't realize that was so dark till I posted it

The 1st gen water temp sensor you mention, I think its a coolant level sensor... I have to double check, but I'm pretty sure..